This thread is going to be a long-term project; if you have read my Parnall Elf construction thread you will know that I’m not a super fast builder, I took nearly 3 years to redesign and build that model, but in that case the model was completed before I started the thread!
With the decision made that my next scale model is to be an SE5a the search begins for a suitable plan; if someone has done all the hard work for you what’s the point in doing it all again and designing from scratch? I will use one of my trusty Laser 70s but was unable to find a suitable plan for this size engine so first some calculations from a simple 3-view drawing downloaded from the Internet.
The first thing to determine is the size; this may not be quite as simple as it seems, a flick through the plans hand book shows models of a similar design i.e. biplane with rigging wires, varying from 80” span for a 48 – 52 four stroke to 56” span for 80 – 90 two stroke (therefore at least a 90 four stroke). The method I use is to work out a minimum size that will allow the engine to be fully enclosed then go bigger to make it the correct size for commercially available accessories, usually wheels. My argument for this method is that you can never have too much power if you need it, but you can always use less throttle and a larger diameter prop to fly in a scale manner. In this instance it equates to 58” span for 5” Williams Bros. vintage wheels.
The next consideration is how scale? As I was going to have to redraw the plan anyway I chose the most accurate I could find, the plan was ordered and then reduced by Prontaprint. I intend to trace the outline then design my own internal construction as I hope to be modifying the plan to allow for some extra scale detail. Before any design work can start I need to confirm the viability of such modifications by making test parts / jigs etc.
One of the notable features on the SE5a is the transparent inspection windows for the aileron and elevator linkage. Here is a photo of the full size taken from a French site where they have restored an SE5a. Click HERE if you want to see all the restoration photos
These need to incorporated for scale authenticity so I want to make them “working” if at all practical.
The first problem is the pulleys; at the scale I’m building they need to be 9mm diameter, I’ve been unable to find any available commercially so turned some from circuit board. I’ll not include a photo; after all, if you’ve seen one pulley you’ve them all but if you’re interested you can use this link to a thread about them http://www.scale-models.co.uk/chit-chat/2363-help.html
Next there are the control horns. These a quite thin and as such would be too weak cut from paxolin sheet, metal seems to be the only viable material. My first attempt uses wire as the “outline” in filled with balsa; this means that the holes don’t have sharp edges that would of course quite quickly cut into the control cables
The photo doesn’t give the correct impression of the shape of the horn, because of perspective it appears to be a lot less tapered than it really is. Although this method seems OK I’m not really happy with it, I’m going to try cutting the horn from sheet steel then use a yoke to attach the cable but just how to make a yoke at this scale I don’t know.
At least I’m now confident that I will be able to use the scale linkage so can start the modifications to the plan.
The redrawing of the plans is coming along slowly, the majority of the outlines are drawn and a lot of the construction detail for the lower wings completed. Before I commit anything to paper, let alone balsa, I build a “virtual” model in my head, at least for the more difficult parts. It doesn’t always work but usually several ideas are scrapped before the final plan is drawn.
I’ve decided, as I’m going to use scale aileron controls, that the most practical solution is to make the top and bottom wings “plug in” as an assembled unit. Still trying to get some suitable carbon fibre tubes to use as both spars and tubes for the piano wire wing pins.
To keep the interest going I’ve started some of the “engineering” jobs that can be done before the final construction details are worked out. I’d previously made the aileron control pulleys so I’ve started on the shackles.
Here are the components:
I’ve used 0.5mm steel for the shackle body and a small split pin for the “eye”. The pin is 1mm brass rod with a 14BA nut soldered to the end to simulate a bolt, when finally assembled I’ll crimp the other end of the pin to secure it as it won’t be visible.
The assembled shackle
With the body bent to shape and the split pin soldered into place I thick the finished shackle looks quite convincing. Remember that the picture above is about 5 times true size (depending upon your monitor), the pulley itself is only 9mm diameter.
“DON’T START TO BUILD UNTIL YOU KNOW HOW YOU’RE GOING TO FIX THE TAIL-WHEEL” is a quote from an article by a well known scale designer / builder in one of the model magazines I read quite some time ago.
Whilst I can see the logic I’m afraid that I’m not that patient, although my plans are nowhere near finished some sections are complete, namely the front of the fuselage, and I want something to hold that looks like a piece of an SE5a!!
It might seem a strange choice but I’ve started the construction with the undercarriage. The reason being that the fixing is slightly complicated to allow for the tensioning of the front flying wires so I decided it would be easier to make the fuselage fit the undercarriage rather than the other way round.
The main legs use 2 pieces of 12 SWG piano wire, these needed some careful bending as they are quite a complicated shape, the rear support uses 1 piece of 10swg.
Before I can silver solder the pieces together I must make a jig to hold everything in the correct alignment.
The undercarriage jig is simply a length of 3x1 timber with a centre line; various screws and panel pins are used to hold the separate pieces of piano wire in their correct positions.
Unless you are exceptionally talented at wire bending and / or very lucky the joins will need a bit of tweaking to get a good fit. When all is ready the joins are held with a twist of thin copper wire, if you don’t do this the unequal expansion as you apply the heat will almost certainly “spring” the joins.
The silver solder flux is “active”, that is it physically cleans the metal as it gets to the correct temperature, but don’t use this as an excuse not to thoroughly clean the joins before you apply the flux and after soldering make sure that any flux residue is cleaned off as it is corrosive.
The thin copper wire will also be removed, as it does nothing for the strength once the join is soldered.
Just the anchor points for the bracing wires to be added and then the assembly can be clad with wood.
With all the silver soldering complete (the large brackets are for fixing the undercarriage to the formers and will be bent to accurately fit when the formers have been made) it’s time to add the wood cladding.
The legs on some SE5a’s were wrapped with linen so hard balsa could be used for the cladding but the particular aircraft I’m modelling didn’t have wrapped legs, they were left as natural wood, so spruce is the material of choice.
As is sadly often the case these days my local model shop could supply me with an ARTF cloned SE5a but a sheet of 1/8 " spruce is another matter! The next best option was a length of “strip wood pine” from B&Q.
All the blanks are fret sawed out, the fronts routed to take the piano wire then clamped and glued using slow epoxy before the rears are routed so ensuring a good join.
I've got a couple of Black & Decker routers but the best way I’ve found to rout the blanks is to use an appropriate sized “ball ended“ router bit fitted to an electric drill in a vertical drill stand, adjust the height to cut half depth of the piano wire. Hold the blank in place and draw round the piano wire then rout down the middle of the lines. The bit doesn’t have to be exact size, once the router has done it’s job a piece of the correct gauge piano wire dragged down the groove will soon make for a good fit.
Some very interesting information there, thanks Barry. I especially like the idea of the “H” section used for the composite strut construction; using aluminium and hard balsa might well end up lighter and stronger than spruce, if we could get any!! Please don’t hesitate to post anything else that you think may be of use, all suggestions gratefully received!
What better on a rainy Sunday afternoon than spending a couple of hours in the modelling room happily “Dremelling” away at the SE5a’s undercarriage?
The first coat of stain has shown up a few areas that require extra work so it’ll be out with the sand paper before the next coat. Then light sanding between coats to build up the “depth” of colour to represent the original hardwood.
As Barry pointed out the stain has really brought out the grain; unfortunately, hoping not to sound too much like British Rail, it’s the wrong type of grain!
For such a high stress part of the aircraft the wood had to be close, straight grained. The way to simulate this is first to give the whole unit a dusting of matt white.
Then "stroke" the painted wood with 120 wet & dry in the direction of the "grain" that you want. Although not very clear from the photo, if you do ever try this technique you’ll find that it’s fairly obvious when you’ve done the right amount of "stroking" to produce the desired effect.
Then apply the stain, again in the direction of the "grain". This is only the first coat but I think it shows that the "grain" is now close and straight.
Time to add a bit of metal work.
First the outline and fixing points are drawn onto thin card that is then covered with sellotape, which both strengthens and protects, before cutting out. The shape is then transferred onto litho plate as many times as required; this is where I hit a problem, I am certain I had another sheet waiting to be annealed but can I find it! I need 4 but 1 will have to do until after Easter when I’ll visit my local friendly printer for a bit of grovelling.
The shape can be cut out quite easily with kitchen scissors, not the wife’s best, it’s a good idea to buy a pair especially for this job. Once the shape is cut out turn it over for final sanding of the edge, this shows up any slight imperfections that would be “masked” by the drawn outline.
The fixings are embossed from the reverse side; “rivets” using an old ballpoint pen, the bolt heads using a nut soldered onto a bolt.
The undercarriage legs are looking a lot better now with a few coats of stain.
The axle fairing is quite a complicated affair consisting of hardwood leading and trailing edges fixed to the undercarriage legs with metal covers top and bottom. The lower cover is fixed but the top cover is hinged for access to the axle and to allow for excess movement of the axle in the case of a heavy landing.
The lower cover is simple to make from litho plate; the strengthening ribs are pressed into a “mould” made from a piece of scrap spruce using soft balsa as a tool and the rivets embossed using a dress makers copy wheel
The LE and TE are joined with cross grain 1/16 balsa to strengthen the litho plate as this area will be subject to quite a battering during take off and landing.
To complete the unit I’ve got to make a “piano hinge” to attach the top cover, then the legs will have the inner litho plate added, the fairing glued and pinned in place and finally the outer litho plate added to the legs.
A heading–hold gyro is definitely the answer for any model that has poor ground handling. The gyro generates a signal when it is moved in a particular plane, not a model plane but horizontally for example. By mounting the gyro accordingly it can monitor yawing, pitching or banking, in this case we use yaw and set the gyro to apply opposite rudder.
A standard gyro only generates a signal while the model is actually moving in the monitored plane but as this correction signal is virtually instantaneous it is quite adequate to smooth out any affect from gusty wind conditions in the air and would possibly be OK on the ground if taking off from smooth Tarmac. Taking off from grass is another matter all together and “ground looping” often occurs before the model has gained enough speed for the rudder to be very effective.
A heading–hold gyro “remembers” it’s orientation as it is switched on and holds the signal until it returns to it’s original heading; they obviously have to be able to be switched on/off using a spare channel otherwise the model would take off and fly straight until it was out of range!
In practice the model is switched on with the gyro switched off at the TX, when ready for take off the model is pointed directly into wind and the gyro switched to “heading-hold”; as soon as the model is airborne the gyro is either switched off or to “standard mode” if the wind is a bit gusty. If the model needs rudder as well as aileron to turn then the gyro needs to be off for the model to turn satisfactorily so in gusty weather there is a lot of “switch throwing” to be done.
As yet I’ve never landed using the gyro as “ground looping” isn’t such a problem as the model is slowing down and isn’t about to leap into the air cross wind but I see no reason why the gyro shouldn’t be used, it would certainly make for a dead straight landing approach!
I decided not to make a separate “piano hinge”; there are two reasons for this:
1) The hinge will not be used that often so the litho plate will be strong enough.
2) The sections of the hinge are fairly long, about ½ inch.
The first job is to make the top cover allowing enough extra material to form the hinge and the front section, mark the sections then cut the front free. The cover is backed with 1/64th ply and the appropriate sections bent down, these will eventually be cut off but for now they will ensure there is sufficient clearance when the other sections are bent around the wire hinge pin.
Here is a photo showing the top cover completed with hinge wire in place; the front section is yet to be started.
The front section is bent around the hinge wire and then the completed top cover glued to the axle fairing.
With the cover closed
With the axle fairing fixed in place the bracing wires can be fitted and a coat of etch primer applied to the litho plate ready for a coat of PC10.
The undercarriage is now finished as far as it can be; the axle is awaiting the arrival of the Williams Brothers 5" Vintage Wheels and the tops of the legs need to be made an exact fit when the fuselage is made.
The gyro I use is made by Futaba and is designed specifically for aircraft; I’ve no idea what the difference is between this and the helicopter type.
The fuselage consists of a fairly substantial front end with a rear section framework from ⅛" square spruce; the front section is built first as a unit and then the rear framework added.
Although the current trend is for interlocking “Liteply” formers I still prefer to use birch ply for these high stress areas. The formers are “notched” to key into the fuselage side doublers; this greatly increases the strength (even though the fit isn’t up to the standard found in CNC cut kits!!).
F2 has a hole cut to suit the fuel tank and consists of 4 pieces glued together for extra strength at the front cabane and front undercarriage mounting points. The rear undercarriage mounting cross member is also made from 4 pieces of ply.
Ply doublers will “tie” the formers together to form the front section.
The front section assembled.
If you’ve read my Parnall Elf thread you may well notice the similarity in design; why change a winning formula? One difference is that I’ve reverted to my preferred method for mounting the engine, which wasn’t the most practical with the highly tapered front on the Elf.
The “engine” bearers are glued and screwed directly to the side doublers; the engine is mounted on a Paxolin plate, which in turn is bolted to the bearers. This method gives great rigidity to the front of the fuselage and also makes changes to the thrust line easier if required.
With undercarriage attached.
The front position for the undercarriage mounting is fixed by F2; this has to be accurately positioned because it is also the mounting for the front cabane struts. Having built the undercarriage first it was an easy job to make small adjustments to the position of the rear mounting cross member to ensure a good fit (in practice it needed to be about 1mm further to the rear than I’d drawn on the plan). Done the other way round, bending and silver soldering the piano wire to fit the fuselage, would have been a lot more problematical!
Showing “engine” bearers.
Another shot showing the wide spacing of the bearers.
I decided that I’d complete the front section of the fuselage, as far as practical, before attaching the rear section thus alleviating the need to swing a 3-foot fuselage around in the confines of the workshop; always a recipe for damage!!
The radiator consists of 2 separate units joined by pipes, the top pipe also incorporates the filler cap, the intervening gap has a metal cover plate; as I intend to use the radiator cap as a convenient fuel filler point I needed to model the 2 header tanks. When trial fitting them I realised that the cover plate would have quite a “double curve” to fit to the rear radiator former (see post #29) and this didn’t seem right. Checking photos showed that in fact the rear radiator former should have a flat top, the transition to curve taking the entire length of the cowl. Wonderful thing hindsight! Now I know the shape of the radiator it’s quite clear on the 3-view drawing, what a difference that thin line makes when you realise what it is!
Luckily the former wasn’t glued in place so a replacement was made and the plan changed.
The grills are made of aluminium mesh from a car accessories shop, stretched to open the slots to more closely resemble the true hexagonal shape of the original. I’ve not yet decided whether to cut the former out behind the mesh or just paint it dark, I my compromise and cut out the top section, which shows above the radiator shutters, and paint the rest.
This shows the undercarriage front fixing; it’s recessed up into the fuselage to allow the front flying wires to pass through the fuselage sides via dummy attachments and be tensioned inside using turn buckles.
I’ve also made a correctly dimensioned “bullet” at the cross over point of the undercarriage wires. The SE5a certainly took streamlining quite seriously, the undercarriage bungy cords are encased and the pilot foot holes have cover flaps.
The next thing I want to do to the fuselage is to fit the cabane struts, but I don’t like to put my trust in geometry for this critical job, especially if it’s my geometry!
This means that before I do this I’ll make the top wing centre section, hold it in position with a temporary jig and then fit the cabane struts thus ensuring that the wing incidence etc. is correct.
If I’m fairly confident that what I’ve drawn on the plan will translate into the actual part when built then I usually make a “kit “ of parts.
The 2 outer ribs are 1/16th ply the others 1/16th balsa made using the “sandwich” method and then the inner ribs are shortened to fit the trailing edge cut away.
The hardwood blocks have a hole for the wing location wires drilled at 5º to give the correct dihedral and grooves routed to fit onto the 1/8 x 1/4 spruce spars. The yellow “pegs” are in fact snake inners tapped 2mm that will have grub screws to lock onto the wing wires to hold the wings in place.
The build starts with the trailing edge.
The centre section is at the stage ready for the fitting of the cabane struts, the top and bottom sheeting will be added later. The carbon fibre leading edge really adds to the torsional strength; the wings with carbon fibre leading edge and carbon fibre spars should be as stiff as a board!
The hard wood wing retaining blocks / spruce spars have had a few wraps of carbon fibre tows, very little weight but tremendous increase in strength for this crucial area.
The cap head set screws will be replaced with grub screws before the top sheeting is added; these are just for a test to make sure that they will hold the wing in place and they certainly will. They only need to be “finger tight” to make the wires solid so a “nip up” with an Allen key and the wings will be going nowhere!
Now the jig to design and get the cabane struts fitted, but first a few days away in the caravan, complete with electric glider of course.
The jig is mainly made from ¼ square balsa using plenty of braces to ensure stiffness; it’s got to hold the centre section rigidly in place whilst the cabane struts and bracing wires are fitted.
The jig in position on the fuselage. It will be held more securely for the final fitting.
The initial fitting of the cabane struts is the check that they will actually line up with the fixing points.
Having confirmed that the lower fixing positions are correct the cabane struts are cut in half. It’s far easier to do the bending and drilling for each end of the struts separately then any discrepancies can be catered for when the two halves are joined, I don’t kid myself that they’ll be perfect first time!
The lower tube has a short length of smaller tube soldered into it to form a spigot for the top tube. The pin through the joint isn’t primarily to strengthen the joint but to stop the balsa cladding, which will be used to streamline the cabane tube, from twisting but it also makes sure that the inner tube will stay in place as the top tube is soldered to it.
A small screw holds the cabane strut to the centre section, those hard wood blocks are definitely multi propose.
Before soldering the cabane struts together all the bracing wires need to be in place, in fact joining the tubes will be the very last job to be done.
When making multiple, or as in this case “handed” brackets, your computer is an extremely useful tool, first draw out the bracket, scan it in, copy and paste the image after “flipping” it if “handed” brackets are needed then print out as many as required. For small brackets such as these I print them onto self-adhesive labels.
To make sure that the brackets will fit I made some test pieces from scrap Lithoplate, as this is dead easy to cut and bend, then the labels are stuck to the sheet material, in this case brass, for the final brackets to the cut.
The final shaping will be done with a combination of Dremel and hand files.
The brackets for the cabane bracing wires have been soldered to the top sections of the struts; all the bracing wires will be cut to the correct length and soldered in place with the centre section held by the jig.
This is a photo of one of the rear struts.
Luckily the end fitting for the side wires are hidden inside the cabane fairings with just the end showing so they can be simple tubes.
This shows a general view of how the struts and bracing wires will go together.
The front and rear bracing wires are a bit more complicated as the end fitting is visible. Once the wire is the correct length with both ends soldered in place the pin will be replaced with a short length of piano wire and the whole lot soldered together.
With the jig and centre section firmly held in position using various clamps the bracing wires are cut to correct lengths. Now would appear to be the time to solder the assembly together but there is a problem.
All those wires will make it very awkward to complete the fuselage top decking but if the decking is completed first it will then make the fitting of the cabanes more difficult!
I’ve decided on a compromise; I’ll finish the front section (the tank cover) as this has a lot of detail with straps, fasteners and the trough for the Vickers machine gun etc. and then finally solder the cabane assembly together before completing the decking back to the cockpit
The end fittings for the front and rear bracing wires are soldered to the wires because with the pins removed they easily take apart.
My original idea had been to use 2 layers of 1/64" ply but I wasn’t convinced that I wouldn’t get some de-lamination at a future date and as this area will be covered in Litho plate it would be difficult to repair, so I opted to use 1 layer of 1/32" ply instead; this is still quite easy to bend, even if it takes a bit (a lot!) longer, so long as the bend isn’t too tight.
Paper templates are used to get the shape before the ply is cut slightly over size. The ply is then covered with boiling water (a good excuse for a cuppa!!) and left to soak for a while, it doesn’t need to be too long. The ply is then tightly bound to a former using masking tape, the former should be slightly smaller than the finished bend, I used a 4" diameter tin for a 2¼" radius bend. Cover the ply completely with the tape and if the former is porous cover that first with cling film then leave it over night. The tape etc. keeps the ply moist; in fact it will probably still be damp in the morning. After removing the ply form the former hold it in its curve either using tape or pins while it finally dries if necessary.
The tank cover doesn’t continue all the way to the side plates. The front cabane struts go through the gap, which has a separate cover plate, so there will be no problem with the final soldering of the cabane assembly.
The gun trough needed a lot tighter bend but as it doesn’t really add to the overall strength just 1 layer of 1/64" ply was used.
PS Where would we be without Red Devil light weight filler!!
Time for a little “metal bashing”; I just love litho plate me!
The first job is to work out the positions for the “extras”, I draw these out, in this case onto the paper templates used to cut the ply decking. I don’t bother drawing to scale but add the necessary measurements then I know for sure where everything fits when I’m in the workshop.
Drilling Litho plate is about as easy as knitting fog, the only satisfactory way to make holes is to use a punch. As each strap has 8 holes and there are 4 straps it is easier to make a simple jig. 2 pieces of ply bolted together then holes drilled through, with the litho clamped in place the drill bit is used as the punch, turned the wrong way round and given a tap with a pin hammer (protecting the business end with another piece of ply).
With the holes done it’s a case of adding the “rivets” and the trimming to size
The 4 straps ready for final finishing.
With the straps, bottom strips and rivets added the finished plate is ready for fitting to the fuselage.
I don’t worry about the odd dent or scratch, I my opinion they just make the finished model look more realistic.
I well remember spending hours trying to get the aluminium cowling for my Albatros just right then finding out that in fact on the full size each panel was individually “hammered” into shape so every one was slightly different with evidence of the manufacturing process clearly visible.
There must be more “recommended” ways to attach Litho plate than there are ways to skin a cat, they’ve all got their pros and cons, and I’ve tried them all! Purely by accident I’ve found what I consider to be the perfect adhesive for the job.
At work we needed some glue that dried clear for a project the students were working on, as I had some “canopy” glue in the car we tried that and it worked fine but some got onto the table which in turn got covered by a small tin foil container used to mix paint in. When it came to tidying up time the tin foil was stuck fast to the table, the old grey matter started to work overtime.
This glue is just the job for Litho plate, it’s like a mixture of PVA and Copydex; it’s thin enough to be spread thinly and evenly over the plate, which can be easily moved to position it accurately but within a short time it has good “grab” to hold everything in place. The icing on the cake is that it’s water based so a quick wipe over with a damp cloth before it’s really set gets rid of any sticky fingerprints etc.
The top panel has 3 distinctive parts; there’s a bulge over the fuel cap, the fuel cap itself and something that looks like a submarine conning tower.
Where the plates will overlap the edge of the under plate needs feathering in, even the thickness of the Litho plate would leave a noticeable step. For filling very thin depths such as this I think the best material is cellulose stopper as sold by automotive paint suppliers.
The bulge is first modelled in balsa and glued to the ply decking and given a coat of silver Solalac for both appearance and fuel proofing.
It is quite difficult to work Litho plate from a male mould so I cut an appropriate sized square from an off cut of 1/8th balsa and started to form the bulge from the inside working it into the cut out, when it was approximately the correct depth I transferred it to the actual model to finish it off.
A small ring of Litho plate and some rivets completes the top plate itself.
It is impractical to make this part from metal so I’ve used spruce and painted it with silver Solalac, when weathered it’ll look OK. When making small parts such as this it’s useful to keep them attached to the wood until they are as near to finished as possible. Sorry for the blurred photo!
The fuel cap is made from brass soldered together.
The result when the parts are assembled
The gun trough was no problem; so that’s the tank cover finished and I must say it’s been an enjoyable few days.
With the way the weather’s been recently it’s a good job I like building as much as flying, it must be a frustrating hobby for the ARTF brigade!
The way I use on Litho plate is very simple, fast and produces perfectly spaced rivets; I use a dressmaker’s copy tool and a straight edge or curved template.
This one has had every other “tooth” removed to widen the spacing.
Mark the position for the rivets on the reverse side of the panel, hold the straight edge or template in place and carefully run along the edge with the tool; a couple of seconds to make a row of perfectly spaced rivets; what could be easier?
The fuselage front section is now as complete as I want it; in a perfect world I would be able to work on the cowl and dummy engine, but before I do I want to fit the engine to ensure I don’t make things unnecessarily awkward for myself later, and in this non-perfect world I don’t have a spare Laser 70! The spars and leading edge for the bottom wing stubs aren’t permanent as yet; these will be built after the fuselage rear framework is attached.
With the cabane struts and all the bracing wires soldered in place I think it’s obvious why I decided to complete the tank cover first.
The first rear frame is built over the plan.
Using an open framework structure has advantages; it is quick and easy to build and very light but it is inherently weak compared to sheet material, to make matters worse the longerons have to be “broken” where the fuselage starts to taper towards the tail.
The strength can be greatly increased by the use of gussets, as always it is a trade off of strength against weight, I use 1/64th ply, which I consider to be a good compromise. One of the modelling magazines had an article that measured this increase in strength and amazingly even gusset made from brown paper made a significant difference.
The second frame is built over the first, which is covered with Clingfilm to stop any unwanted adhesions.
After gluing the rear framework to the front section the longerons are cut ¾ through at the “break” point and carefully cracked to allow them to be pulled onto the rear formers keeping the sides straight. On many aircraft, the Elf for example, the sides aren’t straight; they are pulled in at the rear and allowed to take up the natural bow imparted be the spring of the wood. I used a variation of the “3 pins method” to ensure a straight fuselage i.e. in this case the front formers had marks drawn on the centre line instead of pins.
The framework is made from 1/8th square spruce; when working with this wood I’ve found that the glue takes a lot longer to set, even cyano takes its time!! So it’s essential to use lots of clamps and leave everything to set completely before removing them.
At this stage the rear fuselage is quite flexible, not to say fragile, but with a few more biscuits it’ll firm up.
Strange they’re called biscuits, in the woodwork industry a biscuit is an elliptical shaped piece of wood that is glued into slots cut in two pieces of wood to strengthen a butt joint, very similar to what we have here but significantly different.
The colour will be PC10 and “natural” linen.
Having added a few more 1/64th ply biscuits the framework was a lot stiffer, however I still wasn’t happy about the strength at the “break” line so I removed the cross braces and epoxied some carbon fibre tows over the joint.
Now that’s a lot stronger!
This raises the question why didn’t I do this in the first place? I go on at length about the virtues of carbon fibre tows and then I fail to spot this obvious application; must be something to do with age!
In my opinion it’s never too soon to start on the instrument panel; they’re a mini project in their own right and whilst enjoyable to do it can be a bit frustrating because the model doesn’t seem to “grow” during the time spent on them, so I like to intersperse the work with the main build so keeping the interest going.
Here’s a photo to show what we’re aiming for, it seems a bit daunting but the idea is to concentrate on an instrument at a time.
I’ve made a start; that’s the easy bit!
This will be the final position.
It’s always useful to check that “Pete” will fit!
Starting work on the instrument panel, which has several small pieces of ply and balsa, has reminded me to mention a very useful addition to the workshop.
Like everybody, I suspect, I have a draw (in fact 2 draws) full of “useful” sized off cuts but I also have this old ice-cream container into which I put any small off cuts.
Believe me, there will come a time when you need a piece of 1/16th balsa about 1” x 1” and all you’ll have is a 36” x 4” plank that you bought especially to sheet the leading edge, then you’ll wish you’d not put those little pieces in the bin.
This post will hopefully give you an insight into the thought and build processes that go into making each individual instrument. I decided to start with the air pressure regulator, which is positioned lower left on the instrument panel.
First of all I make a rough sketch showing the main components, which I will include, there’s no way that I could make a true miniature.
Then find suitable bits and pieces, in this case some copper wire and tube to fit, three 14BA nuts, a 2mm crimp, a 2mm nut and some 2mm threaded rod, litho plate and 1/8th square spruce.
The wood has crossed holes drilled through and the wire soldered into position; the small tubes and 14BA nuts are then soldered on. The 2mm rod, nut and crimp are soldered together and the whole lot attached to the body using 5-minute epoxy.
When the glue has set the body is cut down and finally sanded to length with the Dremell
The wire is bent around suitable drill bits and the back plate glued on, again with 5-minute epoxy.
The appropriate bits are then painted with silver Solalac.
Sorry about the blurred photo, taking photos this close really needs a tripod!
The finished regulator in position but not glued, I’ll leave that until all, or at least most, of the instruments are made.
The instrument panel has had a coat of stain as has all the wood that will be visible though the cockpit opening. Note the half round cut outs and the metal brackets.
Another photo of the regulator in position.
The lower wing stubs are built individually; at this stage the front spars are balsa. After leaving everything to thoroughly set they will be removed and the unit slid onto the spruce spars that go right through the fuselage.
Although not obvious from this photo the plans are drawn on tracing paper, this has a couple of advantages, firstly I’ve only had to draw one wing stub, for this one I’m actually working from the back of the plan and secondly it means that since I’m building both wing stubs from the same drawing they should be identical.
With the balsa spars removed the unit can be test fitted to the fuselage.
This shows the front spars and leading edge.
Still thinking about the covering / under camber, all suggestions gratefully received!
Waiting for the glue to set etc. whilst building the wing stubs gave me the opportunity to make the air pump selector; I chose this for no other reason than it connects to the regulator that I’ve already made, but before I go into the construction some general thoughts on instrument panels.
Having a good quality photo of the finished item is very useful and it might seem reasonable to scale the photo appropriately and stick that to the panel but I assure you it would look terrible. Take for example the regulator that I made earlier, it looks completely different from the front, side and top and there are an infinite number of variations between these extremes. A photo is 2 dimensional; our brains compensate to some degree when looking at a photo but put one into a “real” situation, such as a model’s cockpit and it looks just what it is flat! There are also shadows that move dependent upon the viewing angle; a very basic 3 dimensional representation will always look far more convincing than the most detailed photo.
The selector consists of 2 parts, the dial and the lever, so the first thing is to separate these, I do all the manipulation using Adobe Photoshop but I’m sure any photo editing software will do the job. There is an instant problem, some of the wording is missing, so failing more information I’ll make an educated guess and I think it is reasonable to assume that it is “FROM ENGINE & HAND PUMP”. Although I’m sure nobody will actually read the dial I feel that if at all possible the wording should be correct.
From the photo the dial is obviously aluminium, the illusion is created by the use of differing shades to simulate reflections, but once again these won’t work in real life. In the past I’ve used plain grey but it never looked very realistic, so this time I tried a different method and I’m really pleased with the results. I changed the grey to white, which of course doesn’t print out, reversed the image and printed it onto a transparency, when it was completely dry I painted the back with silver Solalac.
I had 3 failures before I managed to cut one good enough, this was then stuck onto 1/64th ply.
I had intended to use the lever as in “decoupage” pictures but it was too fiddlely to work with in paper so I made the lever from shim brass, a 2mm washer and a dress makers pin, all painted silver, the spindle is a 14BA bolt and a brass nut.
The backing is a simple disc of 1/8th balsa with some copper wire and brass tube .
The finished selector.
Notice the shadow has moved to the opposite side of the lever.
2 down, a lot more to go!!
The recent spell of fine weather has produced a lull in the building schedule; not that I’m complaining, it’s nice to have a few good flying sessions this late in the season. Especially as this would have been my first week back at work after the summer break, being 60 has its advantages!
Whilst not being able to get on with any substantial building I’ve contented myself with a couple of instruments: radiator temperature and air pressure. The housings for these are identical, just the dials are different, so once one was done it was a case of “cut and paste”.
The unit consists of the dial and back plate printed as one unit on glossy photo paper and glued onto 1/64th ply, a plastic ring and a disc of acetate. It’s easier to finish the “rounding” of the back plate after everything is glued together.
Without the ring the unit looks like this.
With the ring added the unit looks so much more realistic! The photo doesn’t really show the difference to its full effect.
The instrument labels are simply cut out and glued in place, the wording is quite easy to read. Here’s a photo of the instrument panel so far, you can get a good idea of the size of the individual instruments from this shot
The panel fixers are made using a variation of the “glue drop rivet” system; in this case the glue is mixed with brass paint with a little matt black to tarnish it. With only one more instrument to make for this half of the panel it’s time to glue the instruments in place.
Well the Indian summer continues, I’m glad to say, with the result that the instrument panel is far more advanced than I thought it would be. To finish off the left hand side all that’s required is the petrol selector.
The first job is to turn a knob; no lathe being available I used my Dremmel and a couple of needle files.
The knob is glued to a cocktail stick for easy handling during the preparation and to use as a spigot when gluing to the panel itself.
Once again the back plate is a simple printout glued to 1/64th ply.
The term instrument panel seems a bit of a misnomer; of the 5 “instruments” on this side of the panel only 2 are what I would call instruments but it has certainly made for an interesting build so far.
The small plastic rings added to the temperature and air pressure gauges came from my “useful items” box; these were originally from an electric toothbrush and are used to identify the different heads, I’ve been collecting them for years and just knew they’d come in one day! To try to explain what a difference these small additions make I’d used words like “convincing” and “realistic” but I think Barry’s description “come alive” really says it all.
Here’s another shot of the panel that shows how the acetate sheet in front of the dials brings the whole lot “alive”.
The rear spars don’t go through the fuselage, they are just keyed into the ply ribs, the inner one has a doubler for the rear section. I had been a little concerned that this might weaken the wing stubs too much but with the 1/64th ply covering tying everything together they’re as solid as a rock
The slot is for the rear flying wires, which pass through the wing stubs into the fuselage. As these will have to be threaded through each time the model is rigged I will eventually build in some form of guide tubes but I’ll leave this until the model is test rigged before covering to ensure they’re in the correct position.
This underside photo shows the hole through which the wires enter the fuselage; it will have a piano wire “bearing” to prevent the wires cutting into the fuselage side.
The snake outer for the aileron control is securely attached with a few wraps of carbon fibre tows.
And finally a thank you to everyone for the positive feedback, it certainly encourages me to continue taking the photos and writing the posts. Not that I need all that much encouragement; I find it very useful to recap on the build, I quite often think of a better way to do things so it helps to generate new ideas for the next model.
The cabane struts need cladding, for this I’ve used 3 layers of 1/16th balsa glued together “cross grain”.
They are attached to the struts with 5-minute epoxy, sanded to a streamlined shape, filled and then sanded again.
Before gluing to the struts I decided to add another pin just to be on the safe side!
The top decking from the tank cover to the rear of the cockpit and cladding of the rear cabane struts can’t be done until the instrument panel and all the controls etc. are fitted so it’s time to continue with the rear fuselage. As I mentioned before the rear fuselage is made from 1/8th square spruce and as such is very light but quite fragile, all the joints have had biscuits added which strengthens things up considerably but it was still very flexible.
Flexible is good if you hit something solid, things bend not break; but flexible isn’t so good if it allows the fin and tail plane to move relative to the wings! On the full size they used wire braces but button thread will suffice for a model.
Each section has a cross of thread; the very rear sections will be done after the fin and tail plane mounting is completed. The thread is locked with a drop of cyano at the corners and cross over points; and then given a coat of shrinking dope to finally tighten everything up.
The rear fuselage is now solid and hopefully any too heavy landing will break an easily replaceable thread and not a longeron!
Incidentally that is why the side coverings are laced, for easy removal / replacement during repairs and maintenance.
The right hand side of the instrument panel wasn’t such a challenge.
The 3 dials are just “variations on a theme” and and with 2 being bigger made things that much easier, the hand pump is a .22 cartridge with spruce handle and the flight plan holder is simply printed out twice and assembled decoupage style.
I quite like the “broken glass “ on the oil pressure gauge; a purely accidental scratch but I think very effective and true to life!
Metal panels have in the past caused me problems, but the method I devised for the air pump selector back plate has worked equally as well for the brass identification plate. That is reversing the image, printing it onto a transparency and painting the back with metallic paint; it certainly looks brass and not yellow
The complete panel. Just the compass needed before fitting to the model.
The first former is made from 2 layers of 1/16th balsa glued together “cross grained”, this is a good method when some extra strength is required but it doesn’t warrant ply of even lite ply; it has a 1/64th ply facing on the cockpit side. The other notched former is from 1/8th lite ply as this is also the front fin support. The centre former is also “cross grained” balsa as half the stringers actually end at this point.
Only 2 formers are fully notched because it is very easy to slightly miss align the slots, which results in wavy stringers, not a pretty sight!
The centreline stringer initially holds everything in place. I wanted to use spruce for the stringers but none was available and the model shop didn’t have any idea when they could get any so I’ve used basswood; I don’t think it’s as resilient as spruce but needs must!
The fin rear post is only fitted temporarily; the fuselage end plates have been made oversize to hold the fin post and will be finally shaped when all the stringers are in place.
The centre stringer has had rear doublers and metal brackets fitted for attaching the fin; now to cut the extra slots and fit the rest of the stringers.
A length of cotton is stretched tight between the 2 formers already notched, the intervening formers marked and the slots cut using the Dremell with a cutting disc.
The stringers are added symmetrically; long right, long left, short right, short left and so on, this helps to avoid any unwanted twists in the fuselage.
The stringers stand proud of the formers apart from the first 2½, which will be ply covered, several of the stringers will eventually be removed from this area to save weight. But for now they add vital strength and it’s easier to get things even if all the stringers start from the same point.
Over the last few weeks I’ve been doing a lot of thinking and considerable experimenting with rib stitching before committing to the actual model. Unfortunately the photos I took don’t really show anything of note; white thread on natural Solatex just doesn’t show up any differences!
The first question was “do I want to stitch the fabric?” – No I don’t; it will be a fiddly, time consuming job that will add weight but won’t add significantly to the scale appearance. In fact, as I later found out, at this scale and it must be said with my lack of expertise, the rib stitching looked less like the real thing than the simulated stitching.
So, “do I need to stitch the fabric?” – Yes I do; I know many people have no trouble with under cambered wings but I’ve had the covering pull away on a glider and with a model of this complexity it’s just not worth the risk!
I first tried Barry’s idea of three stitches with the rest simulated, this is where I found out that the simulated stitches looked better, I just couldn’t hide the knots. I rejected this method because with the stitches all being in the same position it would have ended up with three rows of different looking stitches running span wise along the wings, which would have looked very obvious.
Next I tried full stitching; as I had predicted very fiddly and time consuming and it didn’t look that good.
In the end I decided to just “wrap” the thread around the ribs without any knots, each stitch fixed with a drop of cyano. I find the easiest way is use a strip of paper with the stitch spacing marked on it placed along side the rib, make a hole in the appropriate position next to the rib using a pin, then use these holes to pass the needle and thread through.
The centre section is fabric covered on the underside and sheeted to the rear spar on the top; before the sheeting is fitted it shows how I’m doing the stitching.
The centre section has had the top ply added and the covering finished. The rib stitching works well and was no problem to do. With the top frayed rib tape added it really looks the part, the under tape, which I’ve never used before, is quite visible and adds a lot to the finished effect.
Frayed tapes are nowhere near as complicated to make as serrated ones but there is a technique.
The Solatex is marked at the correct width, a small nick made with a sharp blade and the strips torn from the sheet; this ensures that the edges follow the material weave. Discard the first strip with only one torn edge; it will most probably be tapered anyway, then make another nick close to the edge and “tease out” a couple of threads, repeat for the other edge and you have a perfect frayed edged rib tape ready for ironing in place.
I was talking to a friend the other day about the instrument panel; he is also building an SE5a and has a photo which has the instruments in different positions from the one I have. I wonder if perhaps the plane “developed” as a result of reports from pilots about visibility of the instruments whist flying?
He liked the results of my build but said that in his opinion the thread didn’t explain the method fully enough. As I have just started the altimeter here’s a “blow by blow” description; I hope you don’t find it too boring!
I won’t go into the intricacies of Photoshop, but using mainly copy & paste, rotate and distort, the original photo is manipulated to produce an acceptable image with a resolution of 1200 pixels / inch. This is printed on photo paper and glued onto 1/64th ply; you now have to be very patient and wait for the glue and paper to be completely dry.
Cut out, not too close to the image and then sand away all the surrounding material. I use a sanding disc in my Dremel for this but it’s delicate work so be careful and turn the speed to its lowest setting, if you don’t have variable speed it might be advisable to do the last bit by hand. Whichever way you use be sure to always sand downwards away from the dial face, it’s all too easy to delaminate the photo paper.
A cocktail stick and a piece of blue tack make a good holder whilst the edge is painted. Now you have to find or make a suitable ring; a search through the “useful items “ box will often yield a result, in this case the top from an air freshener refill, failing that start from scratch with a piece of Plasticard or similar material.
The ring is now painted and stuck to some acetate using “canopy glue”, which dries transparent, the excess trimmed away and the edge repainted.
All that’s left to do now is to make the adjusting knob, from some plastic sprue, and assemble the parts.
The photo doesn’t show the finished instrument to its best, I just can’t photograph things this small and get the detail to show, but I assure you that once fitted into the cockpit it will look the part.
It seems to have taken longer to do this post than it did to actually make the instrument but I’m sure that’s not really the case!!!
With the centre section removed for covering it’s the idea time to wrap the front cabane struts.
First of all the struts are given a coat of Solalac Clearcoat, which I’ve used for years to help the Solatex to stick.
I know the “industry standard” is Balsaloc, which I’ve also used, but in my opinion it’s nowhere near as good. With Clearcoat the Solatex won’t lift but if you do ever want to remove it, a run over the join with the iron and it can be peeled back without lifting the balsa fibres then rejoined as good as new. When the wing spars in my Albatos Dva broke I removed the entire wing covering from both wings, repaired the spars and then replaced the original covering; saved having to do all that paint work again!
It has another advantage in that the Clearcoat and the Solatex adhesive will bond without the use of the iron. It doesn’t “grab” immediately but if held in close contact it sticks after a few hours. This proved very useful for the base of the cabane struts where there is no chance of applying the iron.
I gave the struts a quick blast with the heat gun just to speed up the bond.
I’ve just spent 3 “modelling” days making the compass and I think it says a lot about scale modellers. Whilst many “sports” modellers voice their appreciation of my models it’s often suffixed with “but why bother?” Well all I can say is “if you feel the need to ask I can’t explain it to you” but I can fully understand their point, the model won’t fly any better and the details will only be visible if you peer into the innards of the model.
The pilots eye view of the instrument panel.
I now think the panel is finished but I’m sure I’ll find a few more things to do to it before it finally gets covered with the cockpit decking. Every time I look at the photos of the full size I notice some thing new but at the moment I don’t consider them worth the trouble adding but that always seems to change!
Just to add substance to my last post about things developing after being “finished” here’s a photo of the compass now with its light!
I haven’t resolved my problem with the headrest; what I have found out is that it was development of the SE5a, the SE5 didn’t have one and neither did some of the early SE5as, whether or not C1096 was one of the early SE5as that didn’t have the headrest I don’t know, but I suspect it was.
Thanks for clearing that up for us Barry, so failing any photographic evidence of C1096 having a headrest doesn’t mean that it didn’t have one at some time; I think I’ll just build her with a headrest, I’m not a competition man so documentation isn’t my God.
Now this proved to be an “interesting” exercise, which after several failures eventually proved to be surprisingly quick and simple. The cockpit has aluminium edging so litho plate is the obvious choice of material but fabricating the channel section stretched my imagination somewhat! I’ll not go into the failures just the final easy and successful method.
The litho plate is clamped against a steel rule using a piece of 1x1 as a backing.
The edge is bent over and the corner filed through using a fine file.
Carefully rolling the dressmakers copy tool along the litho plate produces a nice line of “rivets”.
The long side is trimmed to form an "L" section then using the cockpit as a template the edging is eased into shape; a lot easier than I thought it would be!
With a bead of 5-minute epoxy applied to the edge of the cockpit the aluminium edge is glued in place and the side "tucked under";I think it really finishes the cockpit off.
A point about my previously “finished” instrument panel; whilst investigating the differing layouts, as pointed out by Barry, I noticed on one photo that under the compass there is a level flight indicator. Although I have several detailed photos of the original panel taken from different viewpoints, on all of them the control column is blocking the view of the level flight indicator, which is in the shadow cast by the compass. Now I know that it’s there I can see it, although not very clearly; it has now been added to the model and as per full sized it doesn’t show up all that well, even without the control column.
One problem that has been causing my some concern is the way the top fabric is fixed to the longerons; they appear to use some sort of dome head fixing which shows through the side fabric. The only way I could think of was the “drop of glue” method after all the covering has been applied, but as I said earlier I’m not keen. Why they don’t use flat heads and make life easier for us modellers I’ve no idea!
Whilst searching the shops for something suitable as a basis for making the trim wheel, I came across some very small beads, about ½ mm diameter, which should do the trick if glued to the longerons before the covering is ironed on. These were sold in a haberdashery shop and are for decorating home made birthday cards I think. I must admit that I get some peculiar looks as I rummage through the boxes in these shops, the other customers are invariably women; the things we do in the name of aeromodelling!
Back to the trim wheel, I couldn’t find anything so had to resort to building from scratch; I printed some templates on self-adhesive labels and cut out 3 blanks from 1/32 ply.
These were assembled, the rim marked at 18º intervals and half circles routed out. It didn’t work out as accurately as I’d like but a bit of filling using epoxy and micro balloons made all the difference. After 4 coats of sanding sealer it’s ready for painting.
A coat of silver Solalac, with a few extras the end result is good enough, especially as it will be mounted low down on the fuselage side so only the top section, as shown below, will be clearly visible.
With the majority of the cockpit furniture ready I’ve started on the decking from the tank cover to the cockpit, which is not as straightforward as it might be!
The decking from the tank to about 1/3rd of the way back along the cockpit opening tapers up then it tapers down towards the tail; add to this the fact that there are no formers, only stiffeners, and you can appreciate the problem. I decided the only practical way was to make a jig and build it off the model, as there is a transparent inspection hatch for the Vickers I can’t cheat and add hidden formers.
The cut outs are where the stiffeners fit and you can see by the differing formers how the curvature of the decking has to change.
I clamped a layer of 1/64th ply in position on the jig, gave it a generous coating of watered down aliphatic glue, applied glue to another layer of 1/64th ply and clamped them together.
Then I left it overnight to really dry; in the morning I got a pleasant surprise when I removed the clamps, it held its shape, a bonus I wasn’t expecting.
With the success of the layering technique I decided to try making the stiffeners from 3 layers of 1/32nd ply; the first one is a complete “hoop”. The decking is covered with Clingfilm and the laminations held with small wedges.
Once again I’ll leave it overnight.
The stiffener has worked well and far more evident is the differing lengths of the laminations; with using 3 pieces of 1/32nd ply the inner lamination is about ¼ " shorter than the outer. When these are glued together it helps to explain how they hold the shape.
Before I can make the other 2 sets of stiffeners I’ve got to cut out the cockpit opening in order to alter the curvature of the decking; transferring the top and side views of the opening onto the curved decking isn’t such an easy task. I’ll tape some paper to the decking and then use a lot of trial and error until I get an acceptable outline, make a template from this and only then commit to cutting the wood after checking again that everything looks right!
Well I should have read that last post before I started but it’s too late now! I used a paper template in much the same way . I must say that the stiffener looks and does its job a lot better that I thought it would.
But I have inadvertently caused myself a bit of a problem; with the decking being that much stiffer than I thought it would be it’s quite difficult to get the sides to conform to the correct shape.
With hind sight I should have cut the cockpit opening in both layers before I glued them together and clamped them to the rear former as they dried; I’m sure I’ll get it sorted even if I have to make back section take up all the change in curvature, not quite scale but I’m sure no one will notice.
Before I tried the ammonia on the real decking I experimented with the piece I’d cut out for the cockpit opening, not that I didn’t trust you Barry!!
As I needed to tighten the curve that’s what I tried, as you can see it did indeed hold its new shape and this was a rush job, not left over night.
What is not evident from the photo is just how pliable the wood became using ammonia instead of water and I only brushed it on, I didn’t leave it soaking as I would have done with water.
Having satisfied myself that this was the way to go I tried it on the decking but this time I will leave it over night to thoroughly dry.
I really like this “reverse” jig idea, I’m sure this method will get a lot of use in the future.
Now that the decking is the correct shape it’s time to try and fit it. In order to work around the cabane struts and bracing wires the holes have had to be made quite large, these will be filled after the decking is permanently fitted, but it’s still a bit awkward.
On full size they remove the cabane struts and bracing wires, fit and cover the decking then re-fit them, unfortunately at this size we don’t have the luxury of being able to climb inside to tighten up the nuts!
The instrument panel is a good fit and looks quite “busy” when it’s buried in the fuselage; this is when the shadows and highlights really bring it alive.
It’ll look a bit busier with the clock,altimeter and throttle, which are fitted on the cockpit coaming, and the switch box fitted to the side decking, not forgetting the control column.
I’ll wait and see how much is visible before I decide whether or not to include rudder pedals etc.; weight always has to be a consideration. It’s a bit of a “chicken & egg” situation as the decking has to be in position to check what’s visible but the detailing has to be added before the decking, although the pedals may be able to be fitted from below.
Cutting the inspection hatch and the opening for the Vickers involves marking and cutting straight lines on a curved surface. A good help for this is to use the plastic “banding” that is used to hold cardboard cartons together, these hold their straight edge but easily follow the curve.
Another useful item, to hold things steady at an angle, is a “bean bag”; the better half made me a couple, hence the tasteful floral pattern!
The control column, or joystick if you prefer, is always a prominent part of any cockpit; luckily it’s one part of the SE5a that’s really basic.
The top is a curtain ring, the column itself aluminium tube and the rest various pieces of plastic tube.
With 3 more lengths of snake outer and a lick of paint it’s almost finished.
When the paints dry I’ll bind the top ring with button thread then add the 2 triggers, made from litho plate and that’ll be it; simple!
For some unknown reason the aileron cables are connected to the control column under the pilots seat, this seems strange as in the wing they run very close to the front spar, but as they will not be seen it makes the pivot a lot easier to make.
In the first photo you can see the different components used to make it; white plastic tube, black Plasticard for the flange and collar, toothpick for the grease nipple and a couple of slivers of hex. rod for the nuts. After painting it looks very “ex-works”, but a bit of dry brushing with silver Solalac will soon change that.
I’d originally made the triggers from litho plate but decided they were just too fragile and would soon fatigue with the engine vibration, so these are made from and old “bean tin”.
In the background is my “working sketch” for the top of the control column. We’ll have to wait and see how similar the finished item is to the design.
binding has really improved the look of the control column; first chord all over (button thread), then leather for the top half (Solatex).
After the addition of the triggers with their cables the control column and the pivot can be assembled; with a little weathering, which isn’t obvious from the photo, it looks ready for the cockpit.
The decision that the instrument panel is finished has to be taken at some point and that time has come, so it’s glued in position and the decking added; it’s too late now so I’ll not look at any more photos of instrument panels.
There’s a large cut out for the Vickers.
The view through the inspection panel will determine how much more cockpit detail is needed.
It’s only small but it certainly gives a good view of the Vickers so that’ll need to be quite detailed.
Some of the instruments etc. are actually attached to the decking which makes life a bit awkward to say the least. The left hand side is fairly uncluttered; before I fitted the right hand rear section of decking I glued the radiator flap control lever to the left hand decking.
The right hand side is a lot more complicated; so far I’ve fitted the magneto switches, the main electrical switch box and an aluminium bracket (no idea what it’s for), still to go before I can finish the decking are the hand cranked magneto and the flare box.
The flare box was an enjoyable little project; made mostly from 1/64th ply, just a 1/16th balsa base. No back to save weight, I know the saving is minimal but all these little bits add up!
The flares themselves are from plastic tube with a Plasticard top and a pin for the percussion cap. The clip, made from litho plate, should really be attached to the box but it was easier to cyano it to the flare.
Showing the magneto switches, flare box and magneto in position; it’s now ready for the left hand rear decking.
Below is the start up procedure for the SE5a, I hope the model will be a lot easier!
Like all water cooled engine, the SE is equipped with an expansion tank. It is situated in the cabane leading edge beside the emergency fuel tank. This emergency tank gives you about 20 min flying time at max RPM.
The carburator is fuel fed by pressurizing the main tank with an engine driven compressor or hand pump or both. The emergency works by gravity.
Now let's go and prepare your aircraft for the first flight of the day (Standard procedure)
- Put the airplane in a level attitude using a trestle.
- Fill up the fuel tank.
- Check the oil level.
- Check the coolant level and suck (no kidding) 2 lit.in the expansion tank (use the overflow pipe in the trailing edge, right side of the cabane, and pour the liquid in the radiator)
- Get a stepladder and climb in the cockpit.
- Check mags off and starting mag off.
- Main tank valve off.
- Air selector on hand pump.
- Air release valve on the hand pump off.
- Fuel selector on main to emergency.
- Pressurize with the hand pump. (2.5 on the gauge)
- Open the main tank valve. the fuel will flow into the emerg. tank. Maintain air pressure and don't fall asleep, it's gonna take few min.( 18 lit. )
- You know the emerg. is full when you see fuel comming off the overflow pipe (Trailing edge left side).
- Fuel selector off.
- Main tank off.
- Release air pressure and fill up main tank.
- Pressurize the main tank again.
- Fuel selector on main to carburator.
- Air selector on engine pump.
- Radiator shutters open.
- Two guys on the wheels to do the injections while a third one turns the prop.
- Two guys holdind the tail and a third with fire extinguisher.
- Mixture rich.
- Throttle closed.
- Main tank on.
- Stick fully back (with your knees).
- When ready: starting mag switch on, running mags on 2
- The mecanic bounces the prop,you turn the start mag and catch the engine with the throttle.
- Check oil and air pressure.
- Run the engine four min at 800 rpm.
- Shut the engine down using the mags.(30 sec at 600 rpm).
- Check for air in the coolant circuit (air pockets could dammage the water pipes or the radiator).
- Start the engine again ( you don't need to prime, just open the fuel and turn the prop about 12 blades ) and so on until no air bubbles in the circuit.
- When this is done, put the bird on its tail, start the engine; check all the pressures, water temp(around 60 deg.)mags at 1000 rpm, line up into the wind.
The final decking is just 1 layer of 1/64th ply and the stringers, except the centre one, have been removed to save weight. Small savings behind the CG really do make a difference; the further art the greater the effect.
With the decking finished I had the problem of filling around the cabane struts and bracing wires. It is only 1/32nd thick so the filler itself will have no strength and the rear face is a complex shape with the tubes etc. passing through the curved decking so any backing would be quite difficult to produce accurately. I then remembered a post by Barry about “Micropore” surgical tape and cyano; the tape is self-adhesive and followed the shapes easily, once in position a few drops of cyano turned it into a solid backing. With a couple of pieces of ply to form an edge it’s ready for the lightweight filler.
It took a few applications of filler to get to this state ready for covering; I’ll give it a few drops of cyano to harden the filler before I cover it.
The top of the fuselage is covered in 2 pieces, first all the decking and then the stringers to just behind the cockpit, so the rear decking has 2 layers of Solatex. If I say that covering the decking was a challenge you’ll get the idea, I certainly envied the full size where the struts and bracing wires are removed before covering.
I’m now ready to start on the next section, the fin, skid and rudder but before I do I compare the actual model to the plan. This is for 2 reasons, firstly the plan is amended for those things that didn’t work out exactly as I’d envisaged and secondly it ensures that the next bit will fit what has already been made.
Before I start on the construction of the fin itself I want to be sure that the tail plane incidence adjuster will work so I’ve made that first.
The fin post is a carbon fibre tube through which the adjuster rod, a snake inner, slides; the 2 attachments for the bracing wires are made from closed loop adapters and brass wire.
The lower attachment has a 2mm cap head bolt that will do the actual adjustment by screwing in or out of a length of snake inner firmly fixed to the fin post; I used snake inner for this as it acts like a large “Nyloc” nut so won’t alter the incidence as a result of engine vibration.
Any adjustment required will be made using an Allen key through a small hole in the base of the tailskid fairing.
This is the position it will be fitted in, at this setting the adjustment is about central and can be altered approximately 7mm either way.
The fin is made using “core and half ribs”; for those not familiar with the method it is a simple way to make strong but light structures, especially if the outline is “curvy”. It is my preferred method even for simple shapes such as the SE5a fin, rudder and elevators; the tail plane may have to be a fully built up construction because of the cable and pulley elevator linkage, I’m not decided as yet.
To start the core is cut to the shape of the finished item, the usual material is 1/16th balsa but I’ve heard of the use of thin ply for extra strength or even Depron if weight is an issue. The positions for ribs etc. are marked then one side constructed whilst the core is pinned to the building board, thus ensuring a straight structure. After leaving plenty of time for the glue to fully dry the process is repeated for the other side.
The rudder uses the same method of construction. There’s no separate trailing edge, the core itself does that job; the covering is fastened purely to the edge of the 1/16th core, this works OK because all the edges are eventually taped.
The top and bottom edges have 1/8th x 1/16th balsa added. The balsa is soaked in ammonia for a couple of hours, the pieces for the other side are soaking in the plastic tube, the inner edge is pressed with the back of the scalpel blade to help it bend then it is pinned in place and allowed to dry before gluing.
With the lightening holes cut and the edges sanded all that’s left is the hard points for the hinges and that’s another problem.
I’ll have to make my own hinges to go around the tail incidence adjuster; I could use a commercial hinge for the top but then they wouldn’t match. If I’ve got to work out how to make one I might as well make them all, including the elevator and aileron hinges, happy days!
As the build progresses I’m always thinking in advance, sometimes many months in advance, and one thing that has occupied my mind for a while now is whether or not I should make the tailskid steerable. From a purely practical point of view it isn’t necessary as it is only really used whilst taxiing, which for some reason is frowned upon by our club committee; on the take off run the rudder is effective enough on its own. It is also more complicated, with hinges and linkages to organise, not to mention the extra weight, so all things considered I decided against it.
The problem was I was thinking about it “in isolation”; now I’ve come to actually designing the part it is obvious that because of the tail plane incidence adjuster the skid has got to be separate from the front section and will need some substantial fixings, so they might as well be hinges. The best laid plans of mice and men etc.
The construction is a variation on the core method; in this case the core is a 1/16th ply frame with tongues to locate it in the fuselage, 1/16th ply doublers at the rear where the hinges will fit and 1/16th balsa sides.
The tailskid is made from 1/8th ply with the hinges from brass tube and strip. To avoid the dreaded “metal to metal contact” the hinge pin is a snake with the outer attached using the time-honoured method of stitching with button thread. The top hinge has a washer soldered to it to act as a bearing
Here it is temporarily in position.
The tailskid shroud will be from litho plate and will hide the stitching.
With a steerable tailskid there may well some taxiing going on (when there are no committee members about!!)
If you’ve read this thread from the beginning then you’ll know that I have been giving some thought as to how to make the control horns, which are quite thin; with the tailskid being steerable now is the time to put the thoughts into practice.
Thin steel is really the only option for the horn itself but attaching the cable to it is the problem, a standard clevis would be way too big and a cable passing through a hole would quite quickly be worn through. I hope I’ve solved the problem by bend a “yoke” from thin brass rod.
A thin brass pin goes through the hole in the horn, it’s peened over at the ends and finally the whole lot is soldered to the horn so that the pin isn’t taking the load. The only problem I can see with this is that the attachment point is slightly in front of the horn but I can get around this but slightly altering the angle of the horn and mounting it slightly to the rear.
The skid has a balsa TE extension and is then shaped with lightweight filler where the litho plate shroud will go.
The control is transferred from the horn to the skid via a thin pin to give the servo some “shock protection”, I might also use springs in the cables but from past experience I find these tend to make the steering a bit erratic.
With the shroud fitted that’s the skid virtually finished.
The hinge is a short length of brass tube soldered to a brass strip, which goes around the tube as a safety measure in case the solder joint fails. The pin is 22 swg piano wire and will have a brass “keeper” soldered behind the rudder LE when in position.
The rudder is recessed to allow the hinge line to be central to the radius of the LE which has additional strengtheners added.
The brass strip will be riveted to the fin TE either using brass tube or rod, I’ve not decided which as yet, I’ll be doing some experimenting tomorrow.
The hinges are riveted to the fin TE using brass tube, given a final drop of cyano to securely lock them in place then faired in with some 1/32nd balsa.
As I explained earlier, at this scale “true” rib stitching doesn’t look as good as simulated in my opinion; for the wings I used a compromise which holds the covering to the under camber but looks OK but I can’t use this method for the fin and rudder because of the thin section and the core method of construction.
To simulate the rib stitching a simple jig makes life a lot easier. The thread, I’ve used brown here to show up, is laced around the pins, which are set to the correct spacing, and over the top of the Solatex; to hold them in place I use a tiny drop of thin cyano then give the whole lot a coat of Clearcoat.
Thin strips are cut and tacked in position over the ribs and when the top frayed rib tape is ironed on it bonds everything together. The finished rib tape looks near enough like the real thing for me!
I should have been more careful with the heat gun when shrinking the LE tape around the top of the fin because the covering has pulled back from the TE, but it doesn’t really matter as there will eventually be a litho plate cover running down the length of the TE.
When finishing the fin / rudder assembly I turned up the heat on the iron to shrink the edge tape around the curves, with the covering only attached to the 1/16th edge of the rudder I couldn’t afford any shrink back as happened on the fin. The litho plate shroud conveniently covers that fault and really finishes it off; the hinges and incidence adjuster now look the part.
Incidentally the tapes on the rudder are in fact parallel, for some reason they just look that way on the photo.
The tail plane presents several problems, not the least of which is how to operate the elevators. I prefer to use the same method as the full size aircraft even if this is quite complex, as with the Elf; in that case the linkages were external so easy to check and maintain, but I have reluctantly decided that using the scale closed loop system is not practical for the SE5a tail plane, I still intend to use it for the ailerons. With the rear of the fuselage being open I should be able to hide the non-scale linkage.
The main spar, made from 4mm carbon fibre tube, will have a piano wire pin into the fuselage held by a grub screw similar to the wing fixing; it also acts as a pivot point for the variable incidence. I’ve also used a carbon fibre tube for the TE; this is short because the tail plane tapers towards the tip.
The ribs are cut long so there is sufficient strength around the hole for the carbon fibre TE during construction and are trimmed back later for the addition of a 1/64th ply facing.
Here’s a photo of one half, complete with piano wire pin, ready for the hinges and bracing wire hard points.
The tail is 2 separate units so I’ll connect them with a short length of carbon fibre slid into each TE to ensure that any adjustment to the incidence is equal both sides.
I’ve used the simple but effective core method for the elevators. With hindsight I shouldn’t have cut the lightening holes in the 2 outer bays; because the tail plane tapers down to just 1/16" at the tips there is very little strength left.
I’ve added some carbon fibre tows, which help. The carbon fibre TE joiner is only glued on one side to allow the 2 piano wire pins to slide into hard wood blocks in the fuselage, which are then held in position by 2 bolts tightened through holes in the bottom. If I can find a 0.9mm Allen key long enough I’ll replace the bolts with grub screws; I might have a go at extending the one I’ve already got.
The photo is blurred where it matters; the camera insisted on focussing on the very rear of the fuselage and not the blocks!
Finally a photo of the finished tailskid in position.
For practicality I’m going to bolt it in position, this will mean that I’ll be able to easily remove the skid, fin / rudder and tail plane halves from the fuselage if it becomes necessary. Once every thing has been thoroughly tested and proven, then I may attach the skid permanently as per full size.
I’m only to pleased to pass on any tips that I have, if it encourages more people to advance from ARTFs it’s an effort not wasted! One thing I have learnt in my years of aeromodelling is that you never stop learning; every new model presents new challenges.
I’m not sure whether this is the third or fourth version of the control pulleys but they are now at a stage of development that I feel warrants a trial. The problems that have arisen during tests have been the pulley wheel jamming and the cable jumping out of the groove in the wheel if there was any slack in the system.
Here is a photo of the new components and a finished assembly.
The jamming has been cured by using a larger diameter bush in the wheel and an extra length of tube slightly longer than the thickness of the wheel through which the pin goes; this ensures that the wheel doesn’t bind on the shackle when the pin is peened in position. The extra “arms” on the shackle are bent around the edge of the wheel to prevent the cable jumping from the groove.
Having made 2 pulley assemblies I decided to trial fit them in one half of the tail plane before making the rest. Fitted temporarily and using button thread for the cables has proved that the pulleys are OK but that my calculations for the height of the elevator horns were wrong; they need to be 2mm taller to prevent the cables catching on the covering support.
The final cable runs will all be through the ribs but at this stage it’s just easier to leave them on the outside.
I was talking to a friend about the elevator controls and he wondered why I wasn’t going to use the scale system for the elevators, but was for the ailerons, especially as I’d gone to all the trouble of making working pulleys; so here’s the explanation:
The pulleys have to be incorporated anyway because they are a very “visible” part of the model, but the problem is getting the control cables into the fuselage in such a way as to be useable. If I’d designed the tail plane as a one-piece unit it may have been practical but it just wouldn’t look right and making the tail incidence adjustable would then have been impossible without having gaping holes in the side of the fuselage. With the aileron linkage there’s a lot more room and only one cable per side, which can be attached directly to a servo, should be no problem (famous last words!!).
The elevator control pulleys work far better now that they have their solid attachments and the tubes for the cable runs. The tubes are free if you’re lucky; they are what lengths of piano wire are in when they are delivered to your local model shop and are usually thrown away.
In fact they work so well with the cables connected, at the moment only using button thread, that I’m wondering if it may be possible to actually use them for the elevator control. I’ll get them covered and leave the decision till later; it’ll involve some quite major “surgery” to the rear of the fuselage but if at all possible it will be worth the extra effort.
Here’s a photo of the tail plane in position; the elevators have already been covered.
I have usually covered my models with white Solatex as I find that any colour paint produces a good solid cover over it, but for the SE5a I’m using natural as the underside is plain, doped linen. When I covered the fin and rudder I used scraps of white Solatex for the rib tapes, but for the elevators I used the same Solatex that I’m using for the main covering and this was when I discovered that it is so much easier the fray the natural Solatex.
If you are building a WW1 model and you’re going to fit rib tapes I strongly suggest that you use natural Solatex even if it’s not the best match for your paint, it really is that much easier!
My original thoughts on the elevator control were that the 4 cables would have to run forward to a servo, or more probably a “slave” bell crank, just behind the cockpit. This would involve 4 extra pulleys mounted behind the tail plane fixing block, therefore the cables would have to exit the tail plane at least the diameter of the pulleys plus half the thickness of the fixing block behind the pivot point. This in turn means that if the tail plane incidence needed to be changed, almost a certainty, the cables would move through a considerable distance so the pulley fixings would have to be able to accommodate this; all very complicated and therefore most likely unreliable. Not the sort of thing you want in such a vital system so I decided against!
As I took the photos, for the previous post, of the pulleys with the cables in place I held them tight with my finger and thumb; this is when I had a “eureka” moment, if I twisted my finger the elevators moved!
My idea now is to use a horizontal drum mounted close behind the fixing block with one cable going from the top horn of one elevator, a complete turn around the drum to the bottom horn of the other elevator; a “slave” cable will join the other horns together to transfer the pull.
That’s the theory anyway; I’ll build a test rig and do some experimenting but I’m not going to cut off the “working” control horns just yet! This is still at the early “thinking” stage so any suggestions will be gratefully received.
Well having spent a couple of days with the tail plane on a jig experimenting with various pulleys, drums and bell cranks it’s back to plan A!! The problem in the end was not the pulleys etc. but being unable to get the correct and equal tension in all the cables. The aileron controls will have an adjustable “quick link” where each wing joins the centre sections but with the tail plane there just isn’t the space.
The elevators will actually be moved via a snake and ball link, which will be pretty much hidden inside the rear of the fuselage.
The cables go straight from one side of the tail plane to the other and are for “effect” only but look quite convincing; these photos show the final trial set up on the jig.
The attachment points for the tail plane bracing wires are not bolted on from the outside but attached internally and they are substantial items that exit the structure at acute angles, which would make covering after fitting quite awkward. To get around this problem I incorporated brass tubes into the TE and spar, after covering I passed a brass rod through the tube, soldered the attachment lugs to it and then bent it to the required angle; at this point the attachments were actually free to rotate. To check the angles were correct, and alter the ones that weren’t, before finally fixing them with a drop of cyano I rigged the tail plane using cotton.
Well it’s that time of year again when it’s considered antisocial to spend half the day down the shed building; people to visit, people visiting etc. so I’ll have to content myself with some “quick build” items.
Although C1096, upon which I’ve based the build so far, doesn’t have a headrest my model will as I think it is a quintessential part of the SE5a so this has been my first “quick build”. First a frame from 1/16th balsa and 1/32nd balsa skin.
Then cover with litho plate.
Finally glue in position.
Once the glue’s set I’ll add the frayed tapes over the joints; she’s looking more like an SE5a every day.
“Quick build” project 2 is the Vickers machine gun; about ½ the barrel protrudes from the gun cover and only the rear and right hand side of the stock is visible but I’ve decided to build a complete unit. The extra weight will be negligible and in the event of an untimely end to the SE5a it may be salvageable as a useful item.
The barrel cover is 1/64th ply, soaked with ammonia and bent around 1/32nd ply formers that are temporarily mounted on piano wire to keep things aligned.
The outer skin is litho plate embossed using an old ballpoint pen with the louvers cut and eased out using a scalpel.
The barrel is aluminium tube and the flash suppressor plastic. The whole lot is painted matt black.
The trick now is to take a soft pencil, I used a 9b but anything from 4b upwards is OK, and scrape the “lead” to make some graphite dust, apply this and then carefully burnish with a lint free rag. The resulting finish is a perfect “gunmetal”.
Continuing with the Vickers; here are the basic parts for the stock; the sides are 1/64th ply and the core ¼” balsa.
The “eject side” has an 1/8th lite ply spring cover. You can see the rivets, which were embossed from the reverse side using an old ballpoint pen as for litho plate
The ammo feed shoot is aliminium
It now needs 3 coats of sanding sealer and painting before adding the various levers.
The top covers are from litho plate but the levers need more strength so are cut from a “bean tin”.
The “eject side” having had the matt black and graphite treatment, which really brings out the rivet detail. The extension at the rear is the connection from the interrupt system and will have a copper pipe attached
The levers are pivoted using cut down pins and a 14BA nut and bolt, the handle is stained spruce.
The Vickers has proved to be the ideal “quick build” for this Festive Season consisting as it does of several small parts; I have been able to disappear down the shed for relatively short periods thereby keeping the peace but still managing to do some meaningful modelling.
Talking about tinplate tanks reminded me of an episode from my youth; I went to Apex Models in Leicester (was it in Church Gate?) and there was a ready-made tank and I remember thinking “Why would anyone spend that much money on something you can make yourself?” It was probably about 15p in today’s money but then again I only got 2/6d a week spending money!
To this day I still prefer to make rather than buy but the motivation is different. Take for example the Vickers that I’ve been working on over Christmas; I could have easily afforded to buy a plastic kit, which may well have produced a more accurate replica albeit probably not at 18% scale, but I wouldn’t have got half the sense of satisfaction that I got building from scratch.
Here are a couple of photos of the finished article.
An added bonus is the fact that it was built entirely from the “scrap box”, they don’t come much cheaper than that!
Because the Vickers takes up most of the space under the gun cover a built up structure is impractical and the cover itself can only be thin so I decided to use my least favourite modelling technique; a fibreglass moulding.
For a “one off” I won’t bother making a female mould so first a slightly undersized balsa plug is made, using the piece of decking I removed as a base, filled and sanded smooth.
The plug is then covered with cling film; a useful thing about cling film is that it is in fact to some degree heat shrinkable so it’s relatively easy to get it to conform to the double curves. Then the first layer of glass cloth and resin is added, the only glass cloth I have is very lightweight “wing skinning” woven mat, so several layers will be needed to build up the strength.
Whilst waiting for the resin to cure I remembered that a few years ago my brother give me an off cut of coarse carbon fibre matting, quite loose woven so ideal for forming around double curves, just one layer of this should be sufficient. But finding it was no easy task; somehow it had managed to fall down the back of the shelf, fold itself in half and hide behind a cardboard box, if it had stayed where it was put I’d have seen it when I got the fibreglass cloth out and saved myself a lot of trouble!
The fibreglass was removed and replaced with carbon fibre.
Don’t ask me why I didn’t just leave the original fibreglass in place and put the carbon fibre over the top; I put it down to euphoria about not having to do all those extra layers and too much Christmas spirit (most probably in the reverse order!!).
After leaving to cure overnight the edges are trimmed, the front cut away and the slot for the cabane bracing wire cut. I’ve used carbon fibre tows to put 3 “ribs” on the inside to really stiffen the whole lot up.
Finally a shot of the Vickers in position showing just how little in actual fact is visible from the outside; the stock is partially visible viewed via the cockpit opening and the inspection hatch.
The weight saved by cutting holes in 1/16th balsa is minimal, although it does add up taken over a complete model, but as much as anything I like the aesthetics even if I’m the only one who sees it. I couldn’t use the weight argument with regards to the Vickers because it that case I actually added weight, albeit very little, but I though it worth it, even though not much will be visible on this model, because it is now a complete unit that may be able to be transferred to other models in the future. As for the effort in making the complete gun, it wasn’t an effort it was a pleasure!
One coat of resin was enough to give the required strength but being quite a loose weave meant that it needed a lot of filling but to me this was preferable to working with resin to add extra layers. I can’t say that I’ve really enjoyed this part of the build; from now on it will be OK but it started badly, I think as much as anything because I had the wrong attitude, I knew I wasn’t going to like it and that’s not the way to start things. There are a few more small mouldings needed for the SE5a and for these I’ll certainly try out the brown paper technique first and start with a positive attitude!
The inside of the cover.
The resulting finish will be smooth enough to simulate metal so no need to cover it with litho plate, this is with just one coat of silver Solalac and not yet sanded.
The next job is to make the 2 long “hinges” that attach the cover to the fuselage, they have loose pins, so the cover will be removable but not easily. Once again these are not working hinges, when the model has been painted etc and the cover fitted in place it shouldn’t have to be taken off again (unless I want to show off the Vickers!) so litho plate will suffice.
Here’s a series of photos showing the method of making a hinge.
The litho plate “blank”
The first bends.
The second bends.
Bent around the hinge pin ready for trimming.
The assembled hinge glued to the cover.
When gluing hinges like this it’s obviously important to not glue the pin so use very little epoxy to “tack” the assembled hinge in place, take it apart and fill in any voids with more epoxy. The same applies when gluing to the fuselage.
Some SE5a’s had an extra hatch towards the rear of the cover; I think I’ll add one to take away the plainness. With the bracing wire passing through the cover and the angle of the top “hinge” I didn’t think that it would actually work as such and would really just be used to hold the cover in place, but in fact it does allow the cover to be easily hinged open, I should have had more faith in the designer! Of course now I need to make a convincing mount for the Vickers, as I will be able to “show it off”.
With the extra hatch and the other various fittings added the cover is looking a lot more business like.
With the cover hinged open the Vickers is visible in all its glory.
Yes and yes: the spent cartridges are ejected through a hole in the cover and the deflector plate ensures that they don’t hit the rear cabane strut, presumably gravity makes sure they don’t hit the tail plane! The binding is solatex, a very versatile material.
Here’s a “quick build” that got lost in the confusion. It’s the oil reservoir for the interrupt gear; simply a plastic tube with a carved spruce handle and plasticard supports painted all over gloss black.
It is attached below the instrument panel and points forwards into the foot well. At the moment it’s full length but because of the way it fits it may interfere with the servos so I won’t actually glue it in place as yet. If necessary it will have to be shortened.
While the better half hit the sales I visited the model shop and bought the copper tube for the interrupt pipe and the snakes etc. for the elevator. I’ve now managed to “fix” the positions for the servos and therefore the interrupt reservoir; it didn’t need shortening.
Here’s a “pilot’s eye” view of the completed cockpit. Not much of the Vickers or the interrupt reservoir showing from this angle!
I’m always amazed at the number of models that seem to have had the radio gear added as an afterthought, decent models spoiled by a row of servos bang in the middle of the cockpit. I’m sure with a bit of forethought they could be mounted more unobtrusively and for the last few days I’ve been busy mounting the servos for the rudder and elevator; not the most “glamorous” of building jobs and as such it doesn’t make for a very exciting post, but nevertheless very important; for the moment the control cables are button thread.
What might be of interest is the linkage for the rudder / tailskid; the rudder servo arm has two 2mm bolts / nuts, the “quick links” are cut away to stop them fouling at maximum deflection.
The tailskid servo arm has it’s splined boss removed and is fitted on top of the rudder servo arm by the two bolts. The control cables are connected by piano wire links incorporating a “Z” bend to provide some shock resistance (thanks for the idea Richard).
This photo shows the double-decker arrangement more clearly.
Another thing that perhaps I should point out is that the front servo rail isn’t glued but fixed to the side rails by 2 servo screws. I find it quite awkward feeding servos between fixed rails, especially in the cramped interior of a model, so being able to slide one of the rails to widen the gap is very helpful.
When looking at one of my previous servo installations a fellow modeller pointed out that he wouldn’t be happy with 3 servos effectively held by just 2 screws. Well I’ve used this method for quite some time and had no problems; there’s no way the screws would sheer before the rail itself broke and routine maintenance ensures that the screws are always tight
All the interior work is completed for the rear of the fuselage so the sides can now be covered; this involves a couple of things that I’ve never done before. The cockpit decking is fixed using dome headed screws that are then covered with the linen and the fuselage sides are laced, so I did some tests to try out my ideas first but no “in progress” photos because I didn’t know if the ideas would actually work!
My first idea for the screws had been to use a thin strip of litho plate embossed from the rear but I rejected this because the strip would show through the Solatex, pins would need holes drilling at least partially through the longerons so that was out. In a previous post I mentioned that I’d bought some very small beads, they’re called “Accent Beads”, from a haberdashery store and these have indeed proved to be the answer. I made a small indent using a blunted pin, filled it with slow cyano and placed a bead into it using a dampened toothpick to pick it up. From this photo you can judge just how small these beads really are.
The first job for the lacing is to make a hem on a strip of Solatex; here the fold line has been drawn with a soft pencil and a start made on folding, adhesive-to-adhesive.
When the folding is complete the hem is stuck together using the bare minimum of heat for the iron, we don’t want any shrinkage that would cause bending, then the non-hemmed edge "frayed". One strip is ironed in place first but of course the hem remains unstuck and can be lifted to make the stitching easier; this photo also shows the results of the beads once covered.
The next strip is ironed in place using the first as a guide, the stitching positions marked and pilot holes made with a pin. I found the easiest way to proceed was to stitch about 5 or 6 inches, leaving the stitches very loose, tighten 2 or 3 inches then continue stitching and tightening in sequence.
When the lacing was completed, as far as I can, the whole lot was given a coat of thinned dope to seal everything together. At the wing joints there is an aluminium cover, which is riveted to the front but held by the lacing for the rear section, so the lacing will have to wait until the wing stubs are covered. This will not be until after I’ve confirmed the positions of the wing bracing wires so will be some time yet!
Being the “fair weather” flyer that I am there’s no chance that I’ll venture to the flying field in the next couple of months so it’s the ideal time to remove a Laser from one of my models and get the front end built.
The engine will be bolted to this 2mm Paxolin plate that in turn is screwed to hardwood bearers; there are doublers where the bolts and screws go.
The Paxolin is plenty strong enough to support an engine spinning a well-balanced prop but in the case of a crash it will break before the engine crankcase mounting lugs. (I’ve seen some ARTF trainers with engine mounts made from aluminium easily twice the thickness of the lugs; I just hope they don’t ever crash! Having said that most also seem to use MDS engines so maybe it wouldn’t be such a loss!! Sorry if you happen to like them!!!)
When the plate is screwed in position it adds greatly to the overall stiffness of the front; not that it was weak in any way before. The carb and exhaust are not “set” for this model, in fact I’ve not yet decided whether to use the standard exhaust or make a custom job.
I always use an air filter, when you think about the size of the hole through the carb at full throttle and the amount of dust etc. that gets thrown up during take off I think it makes sense. A small stone would play havoc with the insides of your engine, especially a four stroke; filters are cheap, a new cylinder head isn’t!
I’ve not yet decided on the best method for making / attaching the cowl. The engine cylinder heads project through both sides so the alternatives are to make one unit complete with cylinder heads or individual sides with the cylinder heads attached and a separate top; both methods have their pros and cons but as the starting point is the same for both, the decision can be put off till later.
The initial framework is constructed using the fuselage as the “template” to ensure accuracy.
At this stage the framework is quite flexible so it is firmly wedged in position before the 1/16th balsa skin, which will give it its rigidity, is added.
The rear of the cowl buts up closely to “F2” and what cannot be seen in the above photo is the cling film used to stop the rear former being inadvertently glued to it. The front former is set back because the final litho plate skin will have slots to clear the cabane bracing wires and fuel pipe so the cowl will have to be slid back into position.
A late Christmas present arrived yesterday, a shiny new computer, so not a lot of modelling is getting done at the present whilst I load programs and transfer data etc.
The cling film did its job of stopping things gluing themselves together when the 1/16th balsa top sheeting was added.
Weighing up the pros and cons of my 2 ideas of how to do the cowl proved more problematic than I thought; I kept changing my mind as to the best method, I’m a man of instant indecision!
In the end I’ve decided to go for “Plan C”; the top and sides as separate units all removable, but just how to execute “Plan C” I’m not yet sure, it’ll make the construction more complicated but will have all of the pros and none of the cons of my original ideas.
The top section of the cowl is ready for its litho plate skin but I’ll wait until the lower sections are completed and I know everything fits OK before I do that, a 2mm bolt at the front, which will be disguised by the radiator filler cap, and a peg at the rear hold it securely in position.
From underneath you can see the method of attachment and the carbon fibre used as reinforcement. The “legs” that held it in position whilst the balsa skin was added have now been cut off.
This model is progressing much quicker than my previous (scale) ones, definitely a benefit of being retired! Whilst not a good idea to wish your life away I can definitely say that I think it’s better to be 60 and retired than 59 and 354 days and working.
I’ve made 4 brackets, bent from ½ mm steel and silver soldered, to hold the lower cowl sections utilising the screws that hold the Paxolin engine plate.
It might seem a bit “over the top” using steel for the brackets but being fastened directly to the engine plate they will be subject to vibration. It’s better to be safe than sorry and the extra weight at the front isn’t too much of a problem.
A 1/16th ply plate is glued to the brackets and once again because of the vibration given some physical support by being “riveted” using model railway track pins, then the balsa sides glued to the ply.
I’ve tested the fit of the cowl top and everything is OK so before I do any more to the cowl I’ll get the dummy engine to a point where it too can be test fitted.
A simple balsa frame and 1/64th ply covering makes a good starting point; being a “V 8” engine there’s twice the fun!
There is considerably more work involved in getting the dummy engine to a stage where it can be test fitted than I had anticipated; so much so that I’ve decided that I might as well complete the construction before fitting.
The exhaust flanges were drawn in PhotoShop and printed onto sticky labels; then stuck to1/32nd ply, cut out and glued to the block, which is a simple balsa box.
The lugs for the cylinder head bolts are plastic tube and are actually fitted to the head not the block, they will be faired into the block once they are joined together.
The main construction of the dummy engine is finished and it has been given a coat of silver Solalac, which, as usual, has shown up some areas that need a bit more work. I can now get it fitted temporarily to see how much is visible and add or remove as appropriate.
A photo showing opposite sides of the engine.
At the moment it looks very sparse; it’ll look a lot better once all the “plumbing” associated with an engine like this is added but that’s for later, it’s too fragile to add at this stage.
The cylinder heads and blocks are from cast metal painted black and as such don’t have a smooth finish; Solalac is very good for producing this effect.
First the wood is given a couple of coats of sanding sealer to fill most of the grain then a coat of Solalac; a second coat of Solalac is applied quite thickly and when tacky “stippled” with the brush.
The paint is obviously too glossy as applied, but it shows up the finish nicely; it will have to be “dirtied up” a bit. I’m glad I kept all my broken and cut down 14Ba bolts, they’re just what I needed for the rocker cover bolts, I never throw anything away!
Definitely a 2 bladed prop; I’ve never bothered making “static props” for my models. I’m not a competition man so my models aren’t judged, well only by myself, and they are primarily flying models. If I’ve got some time on my hands and the model’s finished before the flying season starts then this might just be the first to have a static prop.
Before covering the top cowl with litho plate the hinges need to be made. In the past I have tried making non-functional hinges by scoring around plastic rod but they look too perfect for this type of model so I’ll use litho plate and introduce some imperfections (perhaps not intentionally!).
First the litho plate is marked out.
The slots are cut using a scalpel (No. 15 blade) and carefully sanded from the back to remove the “burs” leaving a very thin slot then bent around a length of piano wire.
The flaps are bent out before the piano wire is removed. When the hinge has been glued in position it is faired in using cellulose stopper.
The lower cowl sections have had their litho plate covers attached and the insides painted with silver Solalac. I prefer to use coloured Solalac to fuel proof the engine bay because it is easier to see if you miss anywhere, also if you can see the inside through holes etc. it looks a lot more realistic than plain balsa.
The sides are attached to the engine plate so things don’t look “square” because of the engine down thrust.
The lower cowl in position.
I’ll fit the dummy cylinder heads before I cover the top cowl with litho plate so I’m sure everything will fit together.
A point worth mentioning is that the lower cowl consists of flat plates so for these I’ve used litho plate that hasn’t been annealed; it’s not as easy to work with but in its original state it will remain flat a lot better.
The dummy engine is now glued in position and a start made on the dummy attachment points.
The top cowl is quite a complex shape so the first thing to do is to make a cardboard template, initially from the plan then adjusted as necessary to fit the actual model.
The left hand side was covered first using non-annealed litho plate cut to the above pattern. I suppose it says something about my building that the template needed some minor adjustment to fit the right hand side but then again I wouldn’t be surprised if the full size cowl needed a bit of tweaking to fit correctly!
The cowl is a fairly tight fit around the 2 dummy cylinder heads and with also having to accommodate the cabane bracing wires it is quite a fiddly job to get it into position but once there I think it looks good.
I was talking to a fellow scale modeller recently and discussing our differing ways of building; he likes to do all the construction first and then add details whereas I like to finish, as far as possible, each individual unit as I go along adding as much detail as is practical, of course we still end up with the same end product.
The exhaust starts life as simple tubes rolled from paper; a convenient thing about “rolling you own” is that it is easy to get the correct diameter, just keep adding extra turns until it’s right! I used watered down PVA glue this time and finished of with a coat of thinned shrinking dope.
Holes are drilled, slightly over sized, and the exhaust stubs glued in place with the unit fitted to the engine to ensure everything lines up, then any gaps filled. The rounded front is made from balsa.
Because the exhaust is round the flanges and holes aren’t; if you’re good at maths and familiar with radians you could produce a template but I found it easier to make a jig!
Luckily the front section of the exhaust is near enough 15mm diameter so a piece of copper pipe with a couple of holes does the job.
To make two flanges a strip of litho plate is wrapped around the pipe and held securely with Selotape then both holes carefully reamed out. With the litho plate removed any burrs are cleaned off, the rivets embossed and the outline drawn following the shape of the hole.
One exhaust is ready for filling, the other needs to be cut in half and the centre flange fitted.
I have encountered a problem with the rear exhaust pipes; I rolled them from paper as usual and left them overnight to dry but in the morning they were all bent. I’ve never had this trouble before but these are quite a bit longer, maybe that’s what caused it? I’ve done one leaving it on the former (an aluminium tube) overnight and that has stayed straight so that’s the way to do it, but of course it means I can only make one pipe per day and I need 4 altogether.
With the front exhaust section in position I can tell what detailing needs to be added to the engine; because the “normal” view will be looking down on the model, the spark plugs, which are hidden by the exhaust on the full size, are clearly visible. They are made from a 2mm nut, some plastic tube, a pin and a length of wire.
Being white they stand out quite clearly although the camera doesn’t show them as well as in real life!
Perhaps it’s the angle that I took the photo so here’s one without the exhaust in place that shows the finished effect much clearer.
The lower cowl is held in place by ¼ turn “buttons” that pass through slots, I've modelled these from plastic strip.
The model shop didn’t have any “X” section so I glued 2 “T” sections together then working with small files I shaped the fasteners.
They are pushed through the preformed slots in the cowl and secured from the back with a drop of thin cyano.
It’s all these little things that make cowls one of my favourite parts to make; they are so individual to each aircraft.
The engine detailing is now finished; the SE5a had most of it’s engine inside the cowl so there’s no a lot to see!
On both sides at the front there’s a copper oil pipe with a large brass fitting.
On the left there’s this, (no idea what it does but it’s very prominent). It’s made from a cut down cartridge, in this case a 223, a nut, aluminium tube and copper wire.
Last but not least there’s the take off for the RPM gauge on the rear of the right rocker cover; the flexible drive is 22swg solid core copper wire wrapped with button thread.
Someone recently asked about methods for making corrugated hoses, can’t remember who; I’d never done this before but thinking about it, it would make quite realistic hoses, not true corrugated, it’s a spiral but it would take a very close look to notice the difference. By altering the size of the core and the binding you could produce any size hose you wanted.
Here’s a close up, a bit fuzzy but it shows the general effect.
Whilst I’m sure that the SE5a wasn’t designed with the sole intention of making life difficult for future aeromodellers, at times it certainly seems that way! Most early aircraft would make do with a simple tube for the exhaust but not the SE5a!!
The end of the exhaust is quite a complex affair, the modelling of which involved a lot of “metal bashing” and the construction of a couple of jigs.
The end of the exhaust tube has also had to have some work done cutting apertures behind the louvers and holes and the litho plate will need to be faired in with cellulose stopper before painting.
The full size exhausts are in 3 sections, the front, which consists of the exhaust stubs and collector, the middle section is a straight pipe and then the rear section. I’ve left the model exhausts in 2 sections, at least for now as I work on the brackets.
A coat of silver Solarlac shows up any areas that need more filling, especially where the litho plate joins the rolled paper tube. It may seem strange to go to all this trouble to get a good finish when we want to end up with a pitted “rusty” finish but it is a lot easier to get the right effect starting from a consistent surface.
The front exhaust brackets are very substantial units, but then they need to be, there’s a good length of exhaust pipe to support on the SE5a. I soldered them up from brass tube, squeezed in the vice to make it streamlined section, and brass sheet.
When the bracket is fitted permanently the bolts will protrude from the fuselage so that the nuts are on the outside and obviously the pinch bolt will be cut down to size.
My idea at the moment is for the exhaust complete with brackets to be attached to the engine, which is attached to the lower cowl sides, thereby making the whole unit removable. The rear brackets are a bit of a problem because they aren’t bolted on from the outside, they will have to be made as 2 parts, the arms, attached permanently to the fuselage will plug into the exhaust pipe, I hope!
The next job on the exhaust pipes is to give them an all over covering with a mixture of epoxy and micro balloons; this gives a rough pitted surface ready for painting. The layer of epoxy / micro balloons only needs to be very thin, I find it’s best to spread it with my finger, messy but effective.
When the epoxy has cured, it takes quite a while being such a thin layer, paint all over matt black. This isn’t the final colour, it’s just to make the “rust” less uniform and it also needs to be applied very sparingly, we don’t want any of the pits filled in.
A photo showing one exhaust matt black the other with its coat of “rust”, which is far more varied in colour than is evident from the photo.
On exhausts that are more than just stubs the rust usually follows a distinctive pattern so the rust is painted to reflect this, there is very little rusting in front of the exhaust stubs.
The “rusty pitted” surface is created by the 5 minute epoxy / micro balloon mixture. It’s spread thinly over the entire surface, where more pitting is required leave a slightly thicker layer and keep dabbing it as it cures, I use my finger for this but that’s probably not to be recommended!
To finish the effect use matt black, rust (Humbrol 113) and mixtures of both and dry brush until you’re happy with the result.
I find the best brush to use for this is one with short, fairly stiff hairs and to use progressively drier coats. By finishing off with a virtually completely dry brush the matt black develops a slight sheen so characteristic of exhausts.
When it came to actually making the rear brackets I decided against my original idea and made the strap hinged; I used a thin mylar strip epoxied to the inside of the strap. The brackets are attached to the fuselage by a 14BA bolt through the top flange; I don’t want to drill the longerons so the bottom flange is just held with epoxy, which will be further strengthened by covering with frayed tape.
The pinch bolt would have held the bracket together on its own but the mylar is a bit of “belt and braces” and it will also make sure that there’s no “metal to metal” contact between the bracket and the litho plate end of the exhaust pipe.
I’ve never been entirely satisfied with the original radiator grill and have been looking around for an alternative; unfortunately I’ve not found any cheap DIY type material so have had to resort to buying some etched brass.
The result is a lot more realistic, it’s not true hexagon but it is about the correct size and being so small it certainly looks right. From the right-hand picture you can judge just how small the holes are.
I bought the brass from EMA Model Supplies:
The tank cover side extensions are quite a complicated shape so it makes sense to use a template for cutting the litho plate but taking measurements from the model can be awkward, there always seems to be something that stops you getting the rule in the place you want!
A template is drawn as accurately as possible then scanned into the computer and several copies printed out. Cut one out first and check the fit; if it ‘s OK first time all well and good but most likely you’ll have to adjust the other templates as required, this one needed the front “tab” moving slightly forwards.
Selotape the template to the litho plate and cut out, it cuts easily with a scalpel but the blade won’t be much good for cutting balsa afterwards.
The false hinges are made as described in an earlier post.
Once glued in position the hinges show up very well and really add to the “realism factor”.
Now I’ve got the job of making 60 radiator slats!
First I made one to check the principle but measuring, cutting and bending another 59 as individual items is not really an option because the chances are that there would be noticeable variations so I’ve made a jig. It’s simply a piece of 1mm brass bent to shape with some 0.5mm steel soldered to it to produce a slot 1.5mm deep and twice the thickness of litho plate wide.
The litho plate was cut into 26mm wide strips, the end folded back onto its self then placed in the jig and one flap folded down forming one half of the slat.
The slat was cut from the strip and the process repeated until I got bored, which was after about 20, I then cut the pins to length and “tacked” them in position with a drop of cyano. The flaps were given a thin coat of epoxy, the whole lot put back into the jig and the litho plate bent around the pin.
Once all the slats are at this stage I will modify the jig to enable the other half of the slat to be cut consistently at 1.5mm.
It’s been a tedious, that’s not to say boring, few days but I now have the 60 radiator slats I need. The slats, 30 for each radiator, have to be accurately positioned so are held in a jig whilst being soldered to the sidebars; the pins keep all the slats at the same angle.
The soldered joints are tidied up with the Dremmel then the lot epoxied to the frame, which is made from litho plate; the railway track pins will be used to attach the finished frame to the brackets that hold the unit to the radiator.
Before fixing the radiator slats to the fuselage all that needed to be done was to solder the brackets to the track pins; a simple job or so I thought!
This is where I hit another problem; my “new” supply of track pins won’t solder, they must be made from a different metal. Of course for their intended use in model railways it doesn’t matter whether or not they’re solderable so I can’t really complain.
Anyway it was quite a job removing them without damaging the litho plate so it’s taken all day just to get one side to this stage; I should have checked before gluing them in place but I never gave it thought!
After much delay my 5” Williams Brothers Vintage wheels have arrived; although they are not in their catalogue DB Sport & Scale ordered them from America especially for me at no extra cost, excellent service!
In the past I’ve used Williams Brothers wheels and although they are quite expensive I considered them to be good “value for money” because of the quality and detail of the moulding. As I’m sure you know they recently went out of business, someone else now produces the wheels, and I have to say I’m rather disappointed with the result.
There has been some damage to the mould and because the surface is textured to represent the fabric covering, it will be difficult to remove the blemish without it being obvious. Also the valve detail is poor; it looks as if this is a produced by a separate insert in the mould, perhaps the original has got lost and been replaced with an inferior version.
My idea at the moment is to use Solartex to make a cover, if it works it may well look even better than an “original” Williams Brothers wheel but it’s a job I could have done without.
On to happier things!! Having sorted the method, the second radiator frame went a lot easier than the first and although it’s been quite a fiddly sort of job I’m really pleased with the end result.
When everything’s painted PC10 except for the slats themselves they should make quite a “feature” on the front end.
I’ve decided that something has to be done with the wheels. One thing that everybody seems to complain about with Williams Brothers wheels is the weight; they are heavy but in the past I’ve been prepared to put up with it because of the quality. Having “attacked” the wheels it’s obvious why they’re so heavy, the plastic mouldings are a good 3mm thick, so removing ½ the back is a considerable weight saving exercise in it’s own right.
I started with the back face for a couple of reasons; firstly, if it turned out to be a complete disaster any repairs would be less on show and secondly it lets me see the internal structure. In fact there is very little internally, the two sides are simply joined at the hub and the outer rim so there will be no problem drilling the “valve hole”.
A word of caution; if anybody thinks this is a good idea and is thinking of doing the same I’d wait a while, I’ve never tried this before and could well end up with £20.50 worth of rubbish so I’d wait and see what the end result actually is!
The front face of the wheels has the area between the spokes where the valve hole will be removed, I also reduced the length of the “spokes” as I prefer the look of the wheels where only the first section of the spokes shows through the fabric covering. Before applying the Solartex the surface is wiped over with thinners to remove any residue of mould release agent and given a coat of Clearcoat.
First I tried to cover in one piece, shrinking the outer edge to make the “cone” shape; there was enough shrinkage to take up the correct shape but it proved impossible to get it even. I eventually cut the disc of Solartex along a radius opposite the valve hole, bonded it around the outer edge and cut off the excess then worked towards the centre using the iron
It took me 4 attempts before I got the method right but the finished wheels look just right; not perfect, the “faults” are now as they should be, small creases in the fabric (not obvious moulding faults). The valve hole doesn’t look round in the photo but that’s just the matt black paint, which I’ve painted the insides of the wheels with.
There are various methods of lacing the wheel covers; the one used on the Williams Brothers wheels is a kind of zig-zag stitch similar to the fuselage stitching, there was also a “running stitch” which follows the diameter and probably several more methods that I don’t know about! There are also the ones that apparently don’t have any lacing, at least none that shows, whether or not they use clips I’ve no idea; as far as I’m aware this method was used for the SE5a, on the C1096 restoration there is no rim showing at all.
Whether the spokes show only near the hub or right to the rim depends on the position of lacing and the way the spokes are arranged, if the wheels have the spokes arranged radially then they are more likely to show right to the rim, if they are crossed over, like bicycle wheels, more likely to show just near the hub but it’s really a combination of the two things.
The valves are made from lengths of 2mm brass tube with the ends threaded.
The valves are heated up then “melted” into the rims so the ends show through the valve holes; just the back to cover now, that’ll be no problem as they are virtually flat discs.
When I went the next morning to continue with the wheels I found that the covering had slackened off. I thought this was probably caused by using too much heat to shrink the Solartex; the correct method for complex curves is to apply a little heat, which makes the Solartex pliable, do most of the forming by actually stretching not shrinking, then use a bit more heat for final shrinking, if you use too much heat, the Solartex shrinks OK but after a while it “relaxes”.
With the tyre in place I couldn’t pull the Solartex around the rim so I’d had to use a lot of shrinkage to get the fabric taut; I first made a jig so that I could pre-form the Solartex into a conical shape by stretching, stick it to the wheel then use heat for the final shrinking. The amount of heat needed to get the required shrinkage didn’t seem excessive although I still couldn’t get the Solartex onto the wheel really tight but after a few hours the Solartex was loose again.
For the next attempt I was going to have to remove the tyre, no easy feat with Williams Brothers wheels as they have a moulded lip that presses into a slot, I had to cut off a section of the lip to start with then pull extremely hard to remove the tyre. With the tyre removed I could stretch the Solartex around the rim and as an added bonus there was all the inside of the rim to attach the Solartex to so no chance of the bonding failing, the fabric was tightened using very little heat. After covering the back and struggling to get the tyre back on I went to bed a happy bunny!
The next morning I wasn’t so happy; the covering was loose again, even the back which is virtually a flat disc; this called for drastic action! I tightened the Solartex again with the heat gun, poured some cyano on, spread it around evenly and gave it a blast of activator. I repeated this 3 times, the covering now feels quite solid and it appears to be remaining taut, but I’m not “counting any chickens” just yet!
With the back going slack all I can think of is that it must be some reaction between the covering and the plastic that the wheels are made of causing the Solartex to “relax”, has any one else had this problem?
The wheels have a plastic washer glued to both sides of the hub to protect the Solartex and to make the wheel attachment look more authentic the piano wire axle has brass tube sleeves added. To ensure a slop free fit I cut “teeth” in the end of the tube using the Dremmel and a cutting disc then reamed out the wheel holes with it.
The sleeves have a hole drilled for a split pin then a washer is soldered to form a “back stop”. A useful tip is to use a wooden spring type clothes peg to hold the washer square on the tube whilst soldering.
The sleeves are then glued to the piano wire axle with epoxy. The completed axle is held in position on the undercarriage with “O rings” to provide a certain degree of springing.
As you can see the spoke detail is very subtle just as per the full size, on most commercial wheels it is usually a bit “over done”.
I’ve had fellow modellers ask me why I don’t solder the tubes to the axle, well the simple answer is “It’s easier to use epoxy” and all I can say is that I’ve not lost a wheel yet, at least not one that was attached using this method!
I’ve used the particular batch of Solartex before without any problems; I used “old stock” because I wanted to make sure that the spoke detail was correct, with natural Solartex being translucent it’s difficult to know exactly how it will look when it’s been painted. When I formed it into a conical shape on the jig I left it for a couple of hours to see if it would slacken off but it didn’t, until I attached it to the wheel that is, when it was obvious within a few minutes that it wasn’t going to be any good!
I’ve got a thermometer, which I used to check the temperature of the iron as per the instructions supplied with the Solartex, and marked my variable power supply accordingly but unfortunately I had to use a heat gun for the wheels, which is either on or off, having said that I’ve never had any problems using it in the past.
As I said earlier I intend to use the scale closed loop system for the aileron control and have been giving it some thought over the last few months; here are the results of my deliberations so far and any comments and / or suggestions will be gratefully received.
I can see 2 main areas of concern; firstly the servo will have to pull all 4 ailerons with their associated friction and aerodynamic forces. Even though I’ll be using 2 servos, one will have to pull all 4 ailerons to bank left and the other one will have to pull all 4 ailerons to bank right. Secondly the cables may jump off the pulleys if there is any slack in the system.
The first concern is easily, if not cheaply overcome. I will use “high torque” servos such as Futaba 3010 and a 6-volt battery pack; it’s the second concern that has been taxing the old grey matter!
In a perfect world both servos would move the same amount and there would be no slack, but in the real world, using the differential mix, the servos will have to be set such that the “pull” servo moves less that the “release” servo to ensure that they are not stalled by working against each other but this obviously introduces the “slack in the system” that I want to avoid.
Below is a sketch of the linkage I’ve designed which I hope will alleviate the problem, I will be making a test rig before I commit it to the model so please get your suggestions in quick before I start!
This is how I hope it will work.
To connect the aileron cables the spring is removed and both servo arms and rods moved out allowing plenty of slack to connect the “quick links”, the servos are then moved back to neutral to take up the slack and the spring replaced.
To bank to the left the right servo pulls the bottom right aileron down working against the aerodynamic force, which will keep the cable tensioned, the top aileron is pulled down by a cable between the right ailerons and similarly aerodynamic force will keep the cable tensioned. A cable, via control horns protruding from the upper surfaces, connects the 2 top ailerons so the left ailerons are pulled up and again aerodynamic force will keep the cables tensioned. The cable from the bottom left aileron to the left servo is where the problem arises, here the aerodynamic force, which up until now has taken up any slack, will actually transfer all the slack to this cable run. Added to this, as explained earlier, the left servo has “released” more cable that the right servo has pulled, but because the rod can slide through the servo arm connector the spring will now take up the slack keeping the cable itself tensioned into the pulley.
That’s the theory anyway!
Today I’ve made these, 4 in all, from plastic tube, washers, pins and copper wire.
They are attached to the inlet manifold so I think they are for injecting neat petrol into the engine during start up. Whatever they’re for they fill up the 4 holes in the cowl quite nicely!
The trouble is they appear to hanging in mid air, I might have to add the inlet manifolds to the engine; one job just leads to another!
My starting point for the aileron control is that I’d like to use the scale closed loop system if at all possible because: it’s scale, I like a challenge and, considering that the pulleys etc will have to be included for scale fidelity anyway, if it works my proposed system will be easier to implement. So onto your comments, I probably didn’t explain it fully enough in the first instance but I think David now has the idea.
The rods are not attached solidly to the servo arms but are free to slide through the holes in the connectors, when one servo moves towards the centre it pulls the rod because the connector is in contact with the spring attachment hook, this in turns pulls all 4 ailerons in the desired direction. The other servo moves outwards to “release” the cable but doesn’t actually push the rod; if there is any slack then the spring can pull the rod back through the servo connector. In practice I will ensure that there is always some slack by using the differential mix. The spring tension will not be imparted to the servos but will keep the cable tight into the pulleys, I hope!
The possibility of aileron flutter is something I hadn’t considered, but thinking about it now as far as I can see the spring will only have any effect on the cable run from the last bottom aileron to the servo. When setting up a closed loop system using the Ackerman principle, the “released” cabled actually goes slightly slack and this doesn’t cause any problems so a bit of oscillation in this cable run shouldn’t cause too much trouble. Without having access to a wind tunnel I’ll just have to chance it!
If my system proves not to work I will have to use individual servos in the wings; if to scale the wire joining the top and bottom ailerons will be too thin to use as a push rod so it’s either non scale joining wire or use a separate servo for each aileron, in either case space is a problem. The wing section is very thin; in practical terms I only have about 16mm in which to fit the servo and arm and I’m not sure I could get sufficient throw, especially as the aileron control horns are 23mm long, even using those very thin Hitech servos. I could possibly use the “bent rod and slot” method as used on scale models when the full size has hidden control horns but that’s a method I’ve never used before so would require some experimentation.
The 2 fairings that cover the bungee cord used for springing on the axle will have to be hollow mouldings and they will have to be made in 2 halves so that involves making 4 identical pieces; I think a mould is called for!
First a plug is made from balsa, given a few coats of sanding sealer to produce a smooth surface and a box built around it.
Mould making rubber, a very soft material that melts at a relatively low temperature, is heated over the gas ring and poured into the box to produce the finished mould. The good thing about this material is that when you’re finished with the mould you just melt it down and use it again.
I really don’t like fibreglass / resin moulding so following Barry’s suggestion I tried paper and watered down PVA glue. To get the paper to conform to the shape I had to cut it into strips, it was thoroughly soaked in the glue then 3 layers applied in herringbone fashion. I was surprised just how quickly it set, it can be removed from the mould in a couple of hours and although not thoroughly dry it holds the shape.
This was my first attempt; I did things slightly differently for the subsequent mouldings in that I tore the paper into strips rather than cut it and I made doubly sure there were no air pockets under the first layer before proceeding with the second. This first attempt has been scrapped but shows up the herringbone pattern well, using the torn paper the joins are a lot less evident.
Making these paper mouldings has been a bit of a steep learning curve for me, I think it is really more suited to covering the outside of a shaped form rather than using a female mould as I’ve done, but I have to say I’m happy with the results, which are both light and sufficiently strong. After the pieces had dried overnight the edges had deformed somewhat becoming concave; this was easily remedied by holding them in the correct shape with a balsa template and then heating with the hot air gun, this softened the glue which then hardened and held the correct shape.
As I’m just learning this technique I decided to work on one fairing before I started on the second.
I wasn’t sure if the fairing would fit in one piece, as it does, or have to be left as separate halves, so I did the trimming to fit before joining them, which made things a bit more awkward; hopefully the second will be easier. Once again I’m not trying of a perfect finish, being in such a vulnerable position I’m certain they soon ended up with a considerable number of dents and scratches.
When cutting out the clearance holes for the undercarriage legs it became clear that the thickness of the mouldings wasn’t very even to say the least; I’d obviously used less layers of paper in some places, so for my next attempt I’ll use alternating layers of white and coloured paper, this should even things up.
The “join” is simulated using litho plate embossed with a row rivets and a row of screws, faired in with cellulose stopper. At first I tried using just one strip with both rows embossed and a score line down the middle but I couldn’t form it around the fairing without loosing a lot of the embossed detail, so I used 2 separate strips; this has actually worked out better in the end because the “join” now isn’t perfect, just as the full size. The finished fairings are painted with silver Solarlac so that they will appear to be metal when the PC10 is weathered.
I’m not too happy with the embossed screw detail but at the moment everything is silver, maybe it’ll look better when it’s coloured and weathered, if not I’m sure I’ll be able to think of some way to improve matters.
I’ve made a test rig to check my idea for the aileron linkage.
The hinge point for the top lever is such that there is “built in” slack in the system as it moves from the neutral position; the spring is provided by a rubber band.
This is a photo of the left hand servo after it has pulled the cable; I’ve marked the rod at the contact point with the servo connector.
And this is a photo of the same servo after the right hand servo has pulled the cable; the rubber band has taken up the slack as evident by the mark on the rod. Of course the exact opposite happens with the other servo
The system certainly works, keeping tension in the cable, I’m sure it will work a lot better when I’ve made a proper engineering job of the actuating rods and the sliding bearings.
The front end is covered with litho plate and all those rivets certainly take away the plainness. It looks quite battered but from what little original photographic evidence I can find that’s par for the course.
The radiator drain cock is very prominent; it is made from a M2 nut and closed loop adaptor (I use these a lot and sometimes even for closed loops!!) with a brass cross piece, the body is from plastic tube blended in using 5 minute epoxy and micro balloons. The lot is painted with Humbrol brass paint mixed with a touch of matt black to “weather” it
When faced with the need for lots of wing ribs, in the case of the SE5a 64 ribs and 72 riblets, cutting them out individually is very time consuming and boring, an easy way is the use the “sandwich method”, which involves fixing several balsa “blanks” between 2 “template” ribs. (I’m taking a series of photos of the procedure and will eventually upload them as a “tutorial”)
The root ribs are from 2 layers of 1/16th ply; the first is a “full” rib as shown and then a “skeleton” rib will be glued on when most of the construction is complete
When you see the pile of blanks it makes you realise just how many ribs there are!
The blanks have the hole for the leading edge drilled, using a very sharp drill bit, a ply rib is taped to a set of blanks using the leading edge carbon fibre tube as a guide before drilling the remaining holes with the drill in a vertical drill stand to make sure the holes are straight.
Today I’ve made a complete SE5a rib set and written a “Sandwich Method Tutorial”. I dread to think how long this lot would have taken cutting them out individually!
Although it was a relatively easy job to make the 64 identical wing ribs, being an SE5a it’s not as simple as that! In fact every rib needs to be altered; the mass-produced ribs were a conglomerate of all the rib profiles.
The 20 “aileron” ribs are cut vertically just behind the rear spar hole, these are the only ones that need the rear support tab, which is removed from the remaining 44 ribs; the riblets also have their support tab removed.
With hindsight it would have been easier to make separate templates for the riblets in the first place as I’ve made them now to remove the tabs; it was easier than altering all 72 individually.
One thing I do like about building wings is that you get a lot of model for your effort. A couple of hours after starting and you could convince yourself that the wing is almost finished!
The carbon fibre tubes used for the spars and the leading edge add great strength to the structure, even at this stage of construction.
Wing tips are very vulnerable to “hanger rash” but this method makes them really “ding” proof and is also reasonably light.
The core is 1/16th balsa, cut undersize by the appropriate amount, and then layers of 1/64th ply are glued to the edge; to match the carbon fibre leading edge I’ve used 5 layers of 5mm strips.
Using just 3 layers of 1/64th ply is sufficient to make a really tough wing tip.
The flying wire attachments are fixed to the spars by epoxy and binding with button thread; I didn’t want to compromise the spars by drilling holes at these high stress points. For some unknown reason the inner and outer brackets are of completely different designs.
The inner is bent from thin brass sheet.
The outer is from 0.5 mm steel.
Next to the bracket is the fixing for the inter plane strut and once again it’s a closed loop adaptor! They will enable some fine adjustments to the lengths of the struts and also allow a degree of “span-wise” movement between the top and bottom wing halves, which I think is advisable as they will be permanently joined by the struts, it should help when sliding the wings / fixing rods into position on the centre section.
One wing finished, now I’ve got to repeat the exercise another 3 times!
To alleviate the boredom I’ll do a bit more detailing to the fuselage in between!
The aileron hinges will be the same as I’ve used for the rudder and elevators, both of which use carbon fibre tubes.
The hinges consist of a brass yoke with a brass tube soldered to it and a piano wire hinge pin.
The yoke goes over the carbon fiber tube and has a retaining pin fitted through the 2 holes to prevent the hinge being pulled out, the piano wire hinge pin has a brass keeper soldered behind the control surface leading edge for the same reason.
I have recently received some research material from a fellow SE5a modeller and it has raised a query about the dihedral angle. To save me writing it again, here is a copy of an email I sent:
I've now read the articles you sent me and there is lots of very useful information in them; thanks again.
One thing that is a bit of a cause for concern is the dihedral angle. I'd read several references on the Internet to the angle being 5º and sometimes being reduced by 1º or 2º in the field; I had assumed this was correct because it was confirmed from different sources.
In one of the articles you sent me it says the dihedral angle is 3º 20’; this is very precise if it’s a “guesstimation” so I assume that this is the true angle obtained from factory drawings. Some modifications to my model would appear to be in order; luckily it’s not too late, the wing rods haven't yet been permanently fixed.
To make matters worse I've repeated the 5º angle in my posts in your thread, as well as my own, so that would appear to anyone searching the Internet to be extra corroboration from myself. I'll have to edit the posts to include this “new” information.
Just goes to show that you shouldn't believe all you read on the Internet!
Glad you’ve found the thread useful; any specific questions just ask and I’ll do my best to help.
Both top wings are complete and ready for the ailerons, so before I start on the bottom wings I decided to have a change and go back to the fuselage and build the under pan.
Some SE5a’s had louvers and some had holes; to aid cooling I’ve gone for the latter. It’s very important to have ample escape routes for the hot air; I aim for twice as much as the cooling air that enters the cowl. Here the under pan, made from 1/32nd ply is ready be covered with litho plate, which has been marked out ready for the “rivets” to be embossed.
The litho plate will be glued to the ply before the holes are cut out.
The litho plate is unsupported at the rear because it has to extend back further than the ply backing, for this reason the litho plate is best used non-annealed. Because there are only the 2 side bends and no compound curves the litho plate is still workable in this state.
The finished under pan in position; just the attachment “hinges” to be fitted but as these are quite delicate I’ll leave them till much later in the build.
With the top wings fitted I confirmed the positions of the flying wires where they pass through the lower wing stubs, built in the guides and covered them. Where the wing stubs join the fuselage there is a metal cover riveted to the wing and the front section to the fuselage, the rear section is laced to the fuselage fabric.
When forming litho plate it is sometimes easier to make a former rather than use the model and this is what I decided to do this time. There is a lot of forming to be gone so the litho plate is annealed; the photo shows the effect you get after annealing, the soap has turned very dark brown, nearly black in places.
A “generous” blank is cut; it does help to follow the shape to some degree.
Start the forming using a piece of suitably sized soft balsa until it gets to this sort of stage.
The excess litho plate should now be cut away to allow the final shaping; here the front has been completed.
When all the shaping has been done the part can be finally trimmed to the finished size.
Rivets are embossed using an old ballpoint pen and the lacing holes punched out with a pin. The cover is laced very loosely, glue applied to the faces and the lacing gradually tightened as the cover is manoeuvred into position.
I thought I deserved an easy weekend so it’s on with the top ailerons. As with all things SE5a there are some complications but they are for later, for now it’s just good old “balsa bashing”, very therapeutic!
First the luggage hatch. all that was needed was to cover the section previously remove with Solartex, add a couple of litho plate hinges and a brass fastener.
On this model there is no point in making the hatch openable so the hinges and catch are imitation and the hatch itself is simply glued in position.
Next the steps, being an SE5a they aren’t just holes cut into the fuselage sides as most WW1 planes used, they have a hinged flap that is pushed out of the way by the pilots foot, the flap then closes to fill the hole; this has definite advantages and disadvantages for modelling. The advantage is that there is no need to weaken the fuselage by cutting a hole in the fuselage in an area that is already compromised by the cockpit cut out, the disadvantage is that it is a more complicated build!
I used 2 layers of litho plate. First the “flap” is cut out then the “hole” with a generous surround, the rivets are embossed and the 2 halves glued together and the litho plate formed around the “flap” to give it some depth before finally filing to size.
To cut the arc of the hole the easiest way is to form a close “perforated” line using the point of the scalpel before cutting along the line again with the pointed scalpel, then tidy up with a file.
At this point I have to say that these are not the steps I’ll be using! I had previously drawn the shape to scale and stored it on the computer until it would be required. Today I printed them out onto sticky labels and got to work. When I glued them in place and sat back to admire my handiwork I thought, “WW1 pilots must have had dainty little feet to use them steps!!” A quick check on the size showed that they were in fact only 63% of the required size. Although this has never happened before for some reason the computer had resized the drawing to fit the labels and I hadn’t noticed! The moral is measure twice and cut once.
I’ve made new steps, this time the correct size, no point posting a photo as they look the same as the first ones, just bigger!
One of the rubber “O” rings I’d used on the undercarriage has broken; looking at it carefully it appears to have had small nick, probably by being stretched tight over a litho plate edge, which has subsequently caused the failure. I’ve now used small bungee cord, which should be a lot stronger and while I had the wheels off I fitted the wheel covers.
With all wings built I also tried a test assembly.
Strangely, although the SE5a has a wing span approximately 3 " less than the Elf, it has the appearance of a bigger model.
All the major construction is now finished (it’s only taken 15 months!!) just the interplane struts to do but I’m trying to find some suitable spruce and it’s not easy to come by. I think the final detailing, painting and weathering will probably take another 9 months as hopefully building will take a back seat to flying over the summer.
Although the wingspan is less, the chord is about 50% more, I think this and the blunt front end is what makes the Se5a look that much bigger than the Elf.
I’ve given up on the spruce for the interplane struts and decided to use strip pine wood from B&Q as I did for the undercarriage.
First the blanks are cut out and then bolted together for the final shaping of the profiles.
Once the profiles are correct, a couple of hours with the Dremmel and a sanding block and we have a set of reasonable struts.
The struts will not be attached rigidly to the wings but will be allowed to “swing” slightly in a spanwise direction. To enable this to happen the fixings are (at the moment) closed loop adaptors, which also allow for some adjustment in the effective length of the struts; they are screwed into hardwood blocks drilled and tapped to suit.
The struts themselves will be attached to the fixings by piano wire pins and the whole lot hidden by the interplane bracing wire attachment covers.
I’m having a few doubts about the strength of the closed loop adaptors for this critical job; they are made from brass and I’m wondering if I should really make my own fixings from 2mm threaded steel rod. I’ll certainly give it a go and if it’s not too difficult a job drilling a 1mm hole in 2mm threaded rod then steel fixings it will be!
I have decided to stick with the closed loop adaptors for the inter plane strut attachment points; after all I used them to connect the cabane struts and Warren girders on the Elf and they’ve stood the test of time. Some of the steel 14Ba bolts have sheared off and been replaced but the closed loop adaptors are still fine.
The aileron control horns are made from 0.5mm galvanised steel with 2 pegs soldered in place to make them more secure in the aileron leading edge.
The aileron LE has balsa blocks to support the hinges and one is routed out to also accept the horn, the plate soldered to the hinge pins will add further strength.
As there are 4 control horns, all of which will be interconnected, it is important that they are all as near as possible identical; therefore once they had been “roughed out” I joined them together with a pin through the main actuating hole for the final filing to shape and a jig ensured that they were epoxied in the same relative positions on the ailerons.
I’ve now covered the wings and I have to admit that the Solartex shows no inclination to “lift” from the under cambered section, the wood was pre-treated with Solarlac Clearcoat, which greatly increases the strength of the bond with the Solartex but I’m going to stick to my original idea and also stitch the fabric to the ribs just in case.
Covering is one of my favourite parts of modelling; it is at this stage that the model stops being a “construction” and starts to become a model aircraft. It always gives me a boost to see the “solid” shape of the model.
Then again the boost might just come from the use of copious amounts of Clearcoat in the confines of the shed!!!
I’ve not managed a lot of modelling this last week; at the weekend it was the Teesside Model Flying Clubs’ annual 2 day model air show and a lot of my time’s been taken up helping to get that organised. It was a fabulous weekend and once again we were blessed with excellent weather.
I’ve got 2 of the wings stitched and taped; the stitching went just as I thought it would, no problems but mind numbingly boring! If you’ve every built a scale model and thought that adding stitching and rib tapes just isn’t worth the effort this photo with the evening sun casting shadows might change your mind.
When actually working on the wing the stitching and tapes don’t seem to stand out very much at all, but when in the air and the light catches them they are really noticeable even at a considerable distance so they definitely are worth the effort. Admittedly I’d use simulated stitches if the wing didn’t have such a pronounced under camber.
The wing covering has come to an abrupt halt as I’ve run out of natural Solartex, I didn’t think that it would take more than the 2 rolls but I’ve still got one complete wing to cover and also the top surface of another.
While I wait for the Solartex to arrive I’ve made a start on the Lewis gun. The stock will be made from layers of ply, as the shapes are quite complex I’ve used 2 laminations of 1/32nd ply for each layer to make the cutting easier but it’s still quite a delicate job. The trigger is from thin brass sheet.
With the various pieces glued together and a simple barrel from rolled paper and various bits of tubing it’s starting to take on the semblance of a Lewis.
I’m still searching for something to form the basis of the magazine
I finally found the basis for the magazine, a ring cut from some 32mm waste pipe with a 1/64th ply top. I wasn’t sure how to make the “ribs” but taking inspiration from the excellent models produced by Johnny and GW, to name but 2, I decided to cut the “spokes” from card and it’s worked really well. I’m now on with a second magazine to fit in the holder attached to the instrument panel.
It’s amazing what a few bits of bent tin, half a dozen pins and a coat of paint can do; while there’s no way that this could be described as a “super-scale” Lewis gun it certainly looks the part, a bit of “dirtying up” and the illusion will be complete
It’s been a monotonous few days but the last two wing panels are now stitched and the rib tapes applied, a lot of work with not a lot to show for it.
The emergency tank is from litho plate and shows the results of not following the old adage “ measure twice, cut once”!! The double row of rivets was originally embossed in the wrong place; when I put the litho plate in position it just didn’t look right and a quick check of the measurement showed where I’d gone wrong. Luckily annealed litho plate is to some extent “reworkable” and as the tank will be covered with Solartex a touch of filler completed the repair / alteration.
To work out the positions and sizes of the various bits I used several different photos as well as 3 view drawings; all the measurements required a different conversion factor to get to the actual measurement I needed for the model and I got one of them mixed up.
The retaining straps, which will be added after the tank is covered, are made from “bean tin” material, or to be more accurate corned beef tin material, joined by 14BA bolts, I didn’t think litho plate would be strong enough for this job because the ends are not fastened to the tank but left “floating”.
Before I covered the tank with Solartex I added the flanges for the 2 sumps; it may seem a bit strange to do this but in modelling it is quite often better to do things “in the wrong order” and this is one such case. The sump and flange will look like a single unit in the end but doing things this way the covering was much easier to do and it’s made for an apparent neater edge around the sumps.
The rivets are a lot less obvious now the tank has been covered and the frayed tapes added; the reason the tank is from litho plate and not paper as I used for the Elf is because ironing the Solartex in place would have flattened the embossed rivets.
The sumps themselves were made using the plunge moulding method. They could just as easily been carved from balsa but I like to try out new techniques and although I’ve known of this way to produce plastic mouldings “for ever” I’ve never actually done it before. It really is simple and if you want to see how CLICK HERE.
The next job on the centre section is the Foster mount made from laminations of 1/64th ply. The inner section is 3 laminations with the 2 outer sections having 2 laminations each making 7 laminations in total, which involved some delicate work with the scalpel!
The Lewis gun mount is made from “bean tin” side plates joined by 14BA bolts with brass tube spacers; whilst it will run up and down the track as per the full sized I think it will eventually be glued in position otherwise I’ll have to make a working locking mechanism!
A general view of the Foster mount in position on the centre section.
To ensure that the Foster mount is a good fit on the centre section I first covered the gluing area with cling film, applied a generous amount of 5 min. epoxy / micro balloons to the mount itself and then pressed it firmly in place. The mixture soon becomes like putty and can be moulded to a rough shape, then before it’s had time to fully harden it can be trimmed with a scalpel; it is then left to fully cure.
The Lewis gun mounting is a substantial casting so I’ve used aluminium sheet for the main hoop,
Painted matt black, given the graphite treatment and bolted to the Foster mount carriage it really looks like a substantial piece of metal.
Although not obvious from the photos the front section of the Foster mount has had paper sides added with rivets embossed, these will show up better when it’s painted PC10 and weathered. The gun carriage track is painted using Humbrol brass and brass / matt black
Time for the ailerons; I’m not going to use the “usual” modelling aileron-to-aileron linkage method of a 2mm threaded rod with quick links for at least 2 reasons. At this scale 2mm rod is just too big a diameter and no full size aircraft that I know of uses anything remotely resembling a quick link!
The brackets are bent at 90º for attachment to the aileron spars and consist of a brass bush soldered to thin tin plate with a 1/16th ply “spacer”.
A bracket epoxied and bound to the spar.
The ailerons have one side and the leading edges covered and are then attached to the wings before the other side is covered. A twist of tinned copper wire soldered to the hinge wires and expoxied to the LE acts as a keeper and in this case also additional strength for the control horn.
When it comes time to fit the aileron-to-aileron link wire I’ll either cut an “inspection hole” (the full size has lots of them) in the appropriate panel or remove the panel altogether; I’ll decided which at the time, but at the moment I’m leaning towards removing the entire panel for ease of access.
SE5a’s came in a multitude of colours, most were what we call PC10, which varied from bright green to almost black! Your question about engine size as against prop size is perfectly logical (you must be an engineer) and would appear to be the sensible way of going about things; all I can suggest as an answer as to why we do it this way is that it’s the way it’s always been done, probably because there never used to be much choice of pitch, only diameter, and it’s the way modellers understand. Not really an answer at all is it?
You didn’t seem keen on starting your own “under construction” thread because of your lack of experience but all I can say is that your last few posts would have made an excellent start to a new thread. I’m sure if you mention it to one of the moderators they could move them to a new thread to keep all your SE5a information / queries in one place. But no pressure!
The ailerons are now covered with rib stitching / tapes applied and are “on hold” until it’s time to add the aileron to aileron wire, which will not be until the model is fully rigged and there’s a fair amount of work to do before then.
The interplane struts are given the same treatment as the undercarriage to get the desired finish. The top strut in the photo below has some damage from test fitting the bracing wire brackets; it would obviously have been better to make the brackets and do all the test fitting before I applied the stain, so why didn’t I do that!!!!! Age is a wonderful thing!
The bracing wire brackets are bent up from thin tin plate; litho plate wouldn’t be strong enough. Getting the correct shape to wrap around the struts working from the flat side view was a challenge but PhotoShop came to my rescue yet again, how did we manage before computers?
The top bracket in position.
This is what caused the damage to the strut, any damage will be repaired and the brackets painted before being glued permanently in place.
I’ve no idea what the next project will be. I won’t start thinking about that until the SE5a’s finished, I don’t want to get “side tracked”. There’s still plenty to keep me busy for a few months yet, when the SE5a’s up and flying I’ll wait and hope for a flash of inspiration.
I’m at that awkward stage in the construction; all the major components are complete so for now it’s just "bitting and bobbing" until it’s ready for the paint. To make matters worse nothing seems to be able to be finished, each part needs another so I’ve only got half finished parts.
Getting the end brackets to fit was a lot more difficult than I imagined it would be involving a lot of trial and error. I mentioned earlier that the ailerons are “on hold” and that now applies to the interplane struts.
I’ve made a start on the Aldis sight; the brackets are from 2mm diameter aluminium tube, the sight itself is plastic tube with brass ends.
The reason for the hatch is obviously to give access to the inside of the model and as such it should be as big as possible; I’m sure we’ve all built models that involved extreme contortions of the fingers and much swearing to get the radio gear in.
To this end I’ve made the entire fuselage bottom between the undercarriage legs removable. It’s fixed permanently to the undercarriage, which is attached to the fuselage by a 2mm bolt at the front and 2 small screws at the rear so it’s very quick and easy to remove.
This is the “hole” left when the undercarriage is removed; I shouldn’t have any trouble delving into the “innards” through that!
The “hatch” itself has very little strength being made mostly from 1/64th ply so it is definitely the undercarriage that holds the “hatch” and not the other way round. The screws are really only to hold the undercarriage in position, the front wires go either side of a former and the rear wire fits into a slot in a cross-member, both of which are quite substantial being made from 4 layers of 1/8th ply and it is these that transfer the landing loads to the fuselage doublers. The 2 screws will indeed have to deal with any transverse forces but these should be minimal because from a practical point of view we never land, or take off, crosswind with a biplane of this size, it would be courting disaster to try, I think the undercarriage would be the least of your worries! Once everything is “lined up” the screw holes will be drilled out and a snake inner cyanoed in place to preserve the threads.
The tops of the undercarriage legs are filled to fit to the fuselage “hatch” and then have the litho plate added. Once again it was quite difficult working from the side view to get the correct shape to wrap around the legs, they’re still not perfect on the inside but that won’t be easily seen.
The large rivets were embossed using a pop rivet, before it’s been snapped off, and a sharp tap with a tack hammer. The nut and bolt used to attach the undercarriage to the fuselage is too big to be embossed so I moulded them.
I made the mould using a suitably sized bolt pressed into plasticine.
There’s no fine detail so a mixture of epoxy and micro balloon is OK, if there is fine detail you'll just have to bit the bullet and buy casting resin and proper mould making material.
Once the epoxy mixture is really hard the plasticine can be easily removed and the “bolt head” tidied up. The one on the right has a slight imperfection but a dob of filler soon cures that! A short length of plastic rod converts half the mouldings into nuts.
The mouldings are then cyanoed to the undercarriage; only one coat of paint at the moment just to check they don’t need any more filling.
The windscreen is quite an elaborate affair consisting of a wooden base to which the screen is fastened by adjustable side brackets and then just to complicate things further the side brackets have metal fairings!
The base is from 1/32 and 1/16 ply, the brackets are tin plate with cut down servo mounting grommet bushes soldered in place and the acetate screen has a litho plate edge.
The complete unit will be glued permanently in place after the fuselage has been painted.
Then I’ll have the problem of the fairings! Probably another “plunge moulding” exercise.
The 20swg bracing wires have ends made from brass tube, a time consuming job as there are 40 required all together.
This is where the vast majority of the drag comes from but on the plus side also a great deal of strength. As the bracing wires need to be included for scale effect I see no reason not to make them functional.
I’ve had to move to the conservatory for this job (the cat’s non too pleased), there is just not enough room in the shed to work comfortably with the wings in place. The bracing wires are held temporarily with pins; they will be labelled and removed, then attached permanently after the model is painted.
I’d use a soft brush about 20mm wide and don’t over brush too much, the finish shouldn’t really show brush marks as such but it’s definitely not a “spray” finish. Don’t be too worried about the finish; remember that they didn’t have the filtered air painting booths that are used today! Your models looking good by the way, I can’t remember if I’ve already posted a link to your build thread somewhere in this thread but here it is anyway.
My experiment of “aging” the Solartex by staining with cold tea has failed; a great pity, I like to get away with using “free” materials! The fabric just wouldn’t take up the colour, perhaps it has to be a natural material such as silk, it’s a long time since I read the article and I honestly can’t remember details.
I have to admit that I’ve got no knowledge of Ceconite but personally I’d use Solartex every time; it’s designed for models, it’s a proven method that’s easy to work with and looks good. You say that Ceconite is light but compared to what? It’s designed for full size aircraft not models. I’ve stitched my wings to ensure that the under camber stays in place but most people don’t bother and they obviously don’t have any trouble so I suppose it’s down to a matter of personal choice.
A nice feature on the SE5a is the metal “tread plates” on the lower wing stubs; they have a ridged non-slip surface. It wasn’t clear when I made them if the ridges would look the part so I gave them a lick of paint and tried a bit of weathering before gluing them in place and I’m very pleased with the results.
To produce the parallel ridges I made a jig from20swg piano wire and tinplate. I then embossed the ridges using a length of 10swg piano wire ground to a smooth point.
It took a bit of experimenting to get it right; at first the wires were too long and opened out as I scribed the grooves
Thanks for the run down on Ceconite Barry, it certainly doesn’t sound like a modeling material to me and I’m glad you’re finding the thread helpful Steve; sharing ideas and information is what it’s all about, how would we manage without Lithoplate?
Talking of which, I’ve just fitted the aileron gap covers made from the stuff.
I don’t want to upset any farmers but the covers certainly look a bit “agricultural” but it’s how it’s done on the full size. The cover is bent at an angle to allow the aileron to move; looking from the rear you can see the gap between the cover and the aileron.
The bend in the cover may well be able to be reduced once the correct amount of aileron deflection required has been determined during the test flights.
The cover is split for the aileron horn. In this photo you can also see the drainage holes, I’m not sure whether or not they’ll be visible in flight only time will tell.
The cover has a frayed tape fairing it to the wing. A thing to remember about frayed tapes is that all the edges are frayed. Because Solartex has an adhesive on one side, to start a fray you have to nick the material so you can’t actually fray all the sides. The best thing to do is to fray the long sides and then “fray” the ends when the tape is cut to length.
To do this cut lots of small nicks with a scalpel, turn the tape over and repeat from the other side; it looks right when it’s been ironed in place but a straight cut stands out like a sore thumb.
I was planning on making a start with the paint next week but if this nice weather keeps up flying will take precedence! In the meantime there’s a few bits and pieces to make.
The fairings for the screen are “plunge moulded” as one unit, cut in half, glued to a litho plate base and given a coat of silver Solarlac.
This is where they fit virtually hiding the screen side pillars.
The Vickers front sight starts as 2 rings and some brass rod and tube.
Holes are drilled in the rings, which are still quite thick at this stage for ease of handling and the unit assembled over the template ready for soldering.
The outer ring is a bit too small but to get it correct I’d have to buy a 3m length of 25mm tube, which seemed a bit much considering I only needed about 6mm! As I had some 22mm I decided to use that, it’s near enough for me.
When it’s been soldered the inner “cross hairs” are removed and the rings filed down to a reasonable thickness.
The Vickers is now finished with front and rear sights, the copper “pipe” is for the interrupt.
The Vickers in position.
The magneto handle is made from brass sheet with 2 bead-ended dress makers pins, the larger one has the bead cut in half, epoxied to it.
The base is litho plate; placing the litho plate on some scrap 1/16th balsa, positioning a suitable washer and giving it a firm tap with a tack hammer forms the large ring. With the position marked the litho plate is turned over and the forming around the washer finished off with some hard balsa.
Although I’ve worked with litho plate for many years it never ceases to amaze me just how versatile it is and what complex shapes can be easily formed. A lick of paint, some subtle weathering and the jobs done, but I won’t fit it to the model until after the PC10 paint job.
I think that’s all the “ bits and pieces” made but I’ll take a good look at all my reference photos just to make sure, it’s amazing what you (I) can miss!
Of course not! What I failed to point out in my previous post was that I’d already made the pitot but I had no photo at the time because it was held together by masking tape while the epoxy cured.
The trouble with anything like this, which sticks out from the model, is that it is very susceptible to “hanger rash”. To alleviate the problem it has to be made strong enough to take a few knocks, removable or flexible; they all have their pros and cons but I tend to go for the first option, to that end it’s made from tin plate and copper tube. The “weak point” will be the fixings to the interplane strut so any substantial knock will break them and not the pitot or more importantly the strut.
Went to see Phil at Fighter Aces and bought the Warbirds paint, minus the PC10, which he hasn’t got in stock at the moment. It’s the first time I’ve used this paint, it’s quite thin with a flow more akin to ink than paint and it does take several coats to cover but overall I have to say that I’m very impressed with it. Water based so easy clean up, virtually no smell, quick drying and to top it all, fuel proof!
The model will be entirely brush painted and for the registration etc I’m using my preferred method of permanent marker for the outline. White lettering can be a problem as it’s quite difficult to get white marker pens but a bit of forward planning can save the situation. The area concerned is painted all over white first and the “background” painted in afterwards.
This will be a white “Z” on the top wing when I eventually get a coat of PC10 on. The under surface of the tail plane has been finished with “linen” paint.
The registration markings are printed onto thin card and templates cut out leaving “bridges” where necessary.
The top template above is for black lettering the bottom one for white lettering.
The template is held in position with “low tack” masking tape and the outline drawn.
With the template removed the “gaps” can be filled in using the marker pen and a rule.
Use a fine brush for the edges and then fill in with a flat brush. At this stage they look “too good” but the final “weathering” will take away the “newness” and allow some of the white to show through in places.
I don’t worry too much if I stray slightly outside the lines; remember the original was painted well before the advent of masking tape and airbrushes! If, once all the painting’s finished, I don’t like the look of any part of the lettering then I’ll just do a bit more “weathering” around the offending area and it’ll soon merge in to look OK.
Before marking out the roundels a piece of liteply is taped at the centre position to hold the point of the compass, the circles drawn in pencil and the white blocked in. Then the circles are drawn again, this time using red and blue marker pens, I haven’t got a “PC10” pen for the outer ring. The centre red section won't be painted as yet, it’ll have to wait for the outer ring because I can’t remove the liteply until that has been drawn.
This photo is with 2 coats of blue applied; one more should finish it.
I am using Warbirds water-based paint and when painting the rudder registration and the black “Z” everything seemed to be OK, but to quote from the 1960s “black is black”! When painting the blue, which is quite a lot lighter in colour than the marker pen it became obvious that the paint wasn’t being drawn to the edge of the marker pen ink as is the case when using enamel paint, in fact if anything the paint was being repelled.
It was certainly no easier or better than painting to a pencil line so I’ll be thinking again about the outer “PC10” ring. First I’ll try my home made trammel, I’ve never been happy with the results using enamel paint but maybe it’ll be better with this thin water-based paint.
As on this model I want to replicate hand painted roundels getting a sharp edge isn’t all that important but I’ll now amend my “Hand Painting Registration Letters Etc.” tutorial to include this information
When brush painting to a line it’s far easier to paint from the “coloured side”; this means that when painting the outer edge of the blue ring of a roundel eventually you end up having to reach across the section that has just been painted. A useful accessory is a suitably sized tub placed in the centre of the roundel which helps to ensure that your arm / sleeve doesn’t end up smudging the other half of the roundel.
This one is a Morrisons “healthy eating” coleslaw, courtesy of the better half; I just knew it was the right thing to do to buy good wholesome food!
There are at least two different types of oil filler covers; the Shuttleworth SE5a has is a simple “blister”, the other is flat with “OIL” embossed as used on the French restoration.
To make the “blister” would be another plunge moulding exercise but I thought that the embossed cover would look good when painted and weathered to pick out the lettering.
I first drew the design, with the lettering reversed, and printed out two copies onto sticky labels. One label was stuck to litho plate and “OIL” embossed using an old Biro the other onto 1/64th ply, which was then cut to shape.
The ply was given a thin coat of 5minute epoxy and using the holes as guides the litho plate was held in position with pins whilst the edges were formed first with a hard balsa tool then finally “sharpened up” using a piece of 1/8th square spruce.
I think the finished part will look quite convincing with some subtle weathering.
I’ve not fixed the cover in position as yet because I might use it to hide the access hole for the glow plug connection, but there’s a hinged flap on the other side of the fuselage that might be a better proposition, I’ll make a decision on that latter.
I’ve thought some more about the glow plug connector and decided that it will be best to mount it under the hinged flap and not the oil filler cover. Having made that decision means that it will have to be a working hinge and I have to consider how to keep the flap shut. To ensure that the hinge will take the “punishment” I’ll make it from tinplate so the obvious way to keep it shut is with a small magnet.
The flap and half the hinge are made from a single piece of tin plate
The hinge is bent around a 1mm drill and soldered then the slots cut out with the Dermal and cutting disc. The other half of the hinge is made in a similar fashion, I used a drill as opposed to piano wire to form the hinge around because solder won’t adhere to it.
To attach it to the fuselage I didn’t want to rely on the small amount of gluing area available so the pin is bent at 90º, this will go though a hole in the fuselage side and be securely epoxied inside.
The “catch” is a 14Ba washer soldered into a “cross” slot.
A slight change of plan in so much as I’ve made the hinge pin in 2 halves so as to be able to have a 90º bend at both ends. The backing plate, which will fit inside the fuselage, is 1/8th lite ply, it will give a firm fixing for the ends of the hinge pins and also hold the small magnet.
The hinge pins have a small brass keeper soldered in place, I’ll reinforce it with a layer of epoxy later to prevent any vibration causing the holes to wear.
The flap in position and closed
With the flap open there is a nice sized hole for the remote glow plug connection.
The flap is held securely shut by the magnet working through the 1/32nd ply fuselage sides.
The first thing people seem to look at on any scale model is the cockpit; therefore the padded edging needs careful attention. A good starting point is some split earth wire sleeving. Given a coat of brown paint it’d look just like “brown painted earth sleeving”, so it really does need covering with leather.
I searched high and low for some thin brown leather but couldn’t find any anywhere, then I remembered that I had an old “reversible” leather belt, black one side brown the other. Because it was made from 2 pieces sewn together the leather was not all that thick, but still too thick for what I needed! After separating the 2 halves, more in hope than expectation I fitted a rough sanding drum into the Dremmell, much to my surprise it worked and half an hour latter I had a strip of very thin leather; the down side was that I had produced what seemed to be an inordinately large amount of rather unpleasant smelling dust.
I used contact adhesive to glue the leather to the sleeving. I fitted the split sleeving to some paxolin sheet after first having covered the edge with paper, applied the glue then held the leather in place with clamps and a couple of steel rules.
The observant will have noticed that it isn’t earth sleeving in the photo; for the first attempt I used fuel tubing but the contact adhesive wouldn’t stick to it! I’ve used fuel tubing before with no trouble but this was a new “environmentally friendly” contact adhesive.
The finished padding was first stitched to the fuselage, which was then turned upside down and thin cyano “wicked” around the edge to finally hold everything securely in position.
Another use for the thin leather is the headrest. This is simply a piece of soft 1/4 balsa covered in leather, which is then suitable “distressed”.
The rear section of padding has been added and although not that noticeable in the photo the cockpit edging has also been scuffed.
There’s not a lot going on with the SE5a at the moment as I’m waiting for the PC10 paint to arrive from America. Phil from Fighter Aces tells me it’s on the way so hopefully it won’t be too long as I’m starting to get modelling withdrawal symptoms and the better half is finding me other jobs to do!!
For the centre section tank overflows I’ve used copper wire from domestic house wiring cable; this is very useful stuff, it bends easily and comes in various sizes, this is the earth wire from 2.5mm2 with a 14BA nut and tinplate mounting brackets, which are simply cyanoed into small slots, soldered to it.
The top of the centre section now looks suitably “busy”.
This post is not about a part of the model itself but non the less important for that!
The ailerons need to be joined by a length of thin piano wire, at this scale “quick links” are a non-starter mainly because of their size but in any case there are no detachable linkages on the full size Se5a. Therefore the upper and lower wings will be permanently fixed together by the interplane struts and the aileron linkage; I don’t haven’t enough room to be able to keep the model permanently rigged so this could cause a problem for storing the wings when removed from the fuselage.
I’ve made 2 frames to support the inner sections of the wings; they are in 2 parts and held together with removable pins.
The wings will be stored “hung” from brackets by the top wing, the lower wing supported by the interplane struts and the frame, which grips the trailing and leading edges.
To assemble the model the wing locating pins are pushed a little way into the holes in the centre section and wing stubs, which then take over the support of the wings.
The pin is then removed and the frame disassembled, the aileron controls connected and the wings finally pushed home and the wing retaining grub screws tightened.
That’s the theory anyway!
I’m still searching for things to do whilst waiting for the paint to arrive; I hadn’t intended to do this job until much later in the build but needs must etc.
The piano wire, which links the ailerons, has to be the correct length to ensure the ailerons themselves are at the same angle relative to the main planes. Although they are drawn on the plan I prefer not to rely on these but to make them to fit the actual model; a build-up of tolerances (euphemism for building errors!!) can result in the drawings and model not exactly matching, so first I made an adjustable link.
The landing wires are attached to ensure the correct dihedral angle, the ailerons held at neutral with spring clamps and the link adjusted to the correct length.
The adjustable link is made from a couple of bent pins soldered to some brass screw clamps from my “useful items” box and a length of 2mm rod. Once locked at the correct length the aileron clamps are released, the link removed and a piano wire link bent to the same length.
Fitted in place the link looks a lot better than a 2mm rod attached to control horns by quick links.
When the links are permanently fitted the hole in the Solartex will be covered using a frayed tape with a slot in it, but this will be about the very last thing to do to the model, it won’t be done until all the painting etc has been completed and the wings are joined as a single unit.
I always use silver Solarlac to fuel proof the engine bay; firstly because you can see where you’ve been and more importantly where you’ve missed and also because it shows up any places where the joints are less than perfect and believe me there’s quite a few of them!
You can see where the corner of the engine bearer meets the former there is a slight gap; it’s not a strength issue at the moment but the crevice could hold fuel / oil and eventually it would soak into the wood and cause problems. I’ll fill it and any others with epoxy / micro balloons then give it another coat of Solarlac.
How much “weathering” is appropriate, if any at all, is a matter of personal preference; I like my models to look as if they’ve seen a fair amount of action, others like a pristine, ex-works finish. Also you can see that the lettering looks obviously hand painted, as it should do for a WW1 aircraft; accurate, computer generated transfers just wouldn’t look right.
Some of my comments during this thread such as “ I don’t worry about the odd scratch or dent” may have given the impression that a “weathered” finish is an easy option, I can assure you that it isn’t! To get the correct amount of wear and /or damage in the correct places so as to make the model look “real” is a work of art in itself. Some scratches and dents can be left; others can’t and have to be repaired.
Although WW1 aircraft were not spray-painted, one substance certainly was liberally sprayed about and that was oil! This is where things can go horribly wrong; having spent a fair amount of time painting the model it needs to be “dirtied up”, paying special attention to any white areas. An error now and it’s a re-painting job.
Ideally I’d have finished all the painting before I started on this stage but as I’m still waiting for the PC10 I’ve made a start where I can. Here’s the rudder after this second stage of weathering.
I apply the paint, which is very watered down, with a rag and wipe it in the direction of the airflow slowly building up the “dirt” to what I consider to be an appropriate amount.
The under surfaces of the tail plane really get the treatment, as will the under surfaces of the fuselage and the lower wings.
It is impossible, because of the lack of quality of photographs from the time, to be sure just how weathered / dirty these aircraft became in service but it is clear that the fields got quite muddy so I think it’s a fair bet that the aircraft themselves got equally dirty.
The pitot head is fitted to the R.H. interplane strut; the 2 copper “pipes”, which disappear through a hole in the covering into the wing, are made from twin and earth house wiring, the “hoses” are short lengths of the neutral sleeving. A few years ago I did some wiring work in the house and had the forethought to keep some of the old wire, which used red and black sleeving, the cable available now uses blue and brown.
I didn’t want the pitot head attached to the interplane strut too solidly so that a knock might damage the strut, therefore, I used1.5mm diameter plastic rod. I drilled shallow holes in the strut, pushed the rod through the mounting lug into the hole and applied a drop of thin cyano before trimming the rod over length. A touch with a sanding disc “mushroomed” the end producing a realistic attachment and twists of wire for hose clips finished the job.
Obviously it still needs to be weathered, talking of which, it may sound bizarre but the “dirt” on the underside of the tail plane in the post above is at the moment too clean, it will all be blended in at a later stage by gently rubbing over with a pan scourer.
I’ve just looked back through the last few pages to find out how long it’s been since I ordered the PC10 and it turns out to be just over 2 months. The reason for this is that the “new” PC10 (dark) arrived over the weekend but according to Phil at Fighteraces he’d been sent the old PC10. On further checking with the manufacturers in America it was discovered that this was indeed the PC10 (dark) but it’s nothing like the colour shown on the website and is in fact very similar to the old PC10.
This is the colour as shown on the website when I ordered the paint.
This is the colour that arrived!
The website has been updated in the last few days to show this colour but it’s definitely not what I want for my SE5a so that’s a couple of months wasted. I emailed Chuck Graves of Warbird Colors about this and he pointed me in the direction of some German WW2 colours that are a very close match to the colour I want,
As I’ve said before the colour of PC10 is at best an educated guess and as I’m not a competition man I’ve decided that Schwarzgrun RML70 is near enough for me.
The paint has had some talcum powder added to produce a nice matt finish and obviously still needs to be weathered but I think it looks a lot better than the lighter shades.
The templates for the white lettering are what I call “positive”; that is they are the actual shapes, which I draw around, not holes cut out. Here a card “Z” is held in position on the fuselage side with low tack masking tape.
I don’t know about you, but I find painting rather boring, not weathering, which I enjoy, as it really brings the model to life and makes it an individual “miniature aircraft” as opposed to a model. It’s the slapping on of the overall basic colour that really drags, especially with the prospect of having to apply 3 or 4 coats around a fairly complex shape as below.
There are a couple of things I do to relieve the boredom and a couple of things I don’t do. The photo above shows one of each! I do, if practical, split the painting into smaller sections. The section behind the rear white stripe has had 2 coats and the rear edge of the “Z” made a convenient place to stop the next section, the first coat will be continued forward before applying the second coat and so on. I don’t use a thick coat of paint to reduce the number of coats required, it may indeed reduce the number of coats of paint but the chances are that you’ll end up spending a lot of time and effort trying to remove sags and runs from the paint and the finish will never be as good as a build up of thin coats. You can tell from the area with only one coat that the paint is quite thin, it hasn’t covered very well but the second coat is a great improvement. Another thing I don’t do is rush the job; I always allow ample time for one coat to dry completely, not just “touch dry”, before applying the next.
Another thing I try to do to alleviate the boredom is to take breaks from painting and do a bit of detailing. Unfortunately I have done most of the small detailing work whilst waiting the 2 months for the paint to arrive, but there have been a couple of things to make.
The control for the radiator slats. It doesn’t show up very well, I’ll take another photo after the front has been painted.
The tubes from the pitot head exit the wing at the root and are encased in the rear cabane strut.
The other hole in the covering is for access to the aileron control cable adjustment and will be patched once they are set up correctly.
I had the comment made to me that it was a pity to “spoil” the covering by having to use patches. Well just have a look at this photo of the Shuttleworth SE5a.
This is an aircraft that doesn’t fly that often, is lovingly maintained and certainly doesn’t have to take the sort of punishment handed out on a WW1 airfield.
The painting of the fuselage is now finished; the individual pieces were painted separately then fitted in place ready for weathering, this will ensure that the weathering “flows” from panel to panel in a natural way.
I need to leave it for a while to let the paint really harden off before I start wearing it away with a pan scourerer, that’ll really show up the rivets and panel edges etc. Only when I’m happy with that stage will I start to “dirty” it up a bit.
Here’s a better shot of the control rod for the radiator slats.
There’s lots of “damage” to the lower part of the front panel, which will eventually be very heavily weathered with chipped and worn paint.
“Dirtying up” the fuselage has been a bit of a hit and miss affair; with the PC10 being very dark it’s hard to tell where the very thin black paint has been applied and how much it may have built up in places, until it’s actually dry that is and by then of course it’s too late to do any corrective work if there’s too much build up of paint.
The finished effect needs to be quite subtle and I’m not happy with the front section, that is in front of the oil cover, so this area will be repainted with PC10 and the process repeated. The other side has worked out OK.
As far as the wings and tail plane are concerned the parts to concentrate on are the areas behind the hinges and the leading edges, but once again the effect is quite subtle. The colour of the paint in the photos varies depending on how the light falls on it, but this is not as noticeable in “real life”.
The roundels on the top wings also need careful attention; the stitching really picks up the “dirt” and the area behind the hinge, which is hidden by the aileron gap cover, shows up a lot more than on the PC10.
I can assure you that the roundels are round; it’s just the way it looks in the photo!
Another photo showing how the dirt picks out the stitching.
Richard, it seems a long time ago that I was working on producing a nicely stained undercarriage and to some it may seem like sacrilege, but this is what it looks like now!
As for the colours, it was really the Germans who went for the “flashy” paint schemes and very nice models they make too, perhaps the British were / are too reserved. In the photo of the Shuttleworth SE5a you can see how dark the PC10 is, this is a latter variation, some of the earlier ones were a lot lighter, but whatever base colour was used the red wheel covers are about as far as they usually went, although there are one or two examples of fairly bright “nose art”.
Of course as I’ve said on several occasions, PC10 was not a colour as such; it was the 10th variation of Protective Coating and consisted of several layers of clear dope, undercoats, etc., etc.
I’ve repainted and weathered the offending front section of the fuselage and am now happy with it.
The elevators are actually operated by a pair of pushrods but I want it to look as if the scale control cables and pulleys control them. To do this I will run a cable from the top control horn on one side to the bottom control horn on the other and vice versa; to take up any slack I will include springs in each cable run.
The first thing to do is to find out where any slack in the system may be by temporarily joining the elevators together and connecting the control horns with cotton. I did each cable separately to ensure there wasn't any interaction.
Moving the elevators from full up to full down showed that there is in fact no noticeable slackening or tightening of the cables; more by luck than judgement I’m sure! I’ll still incorporate the springs but with just enough tension to stop the cables flapping about
I made up the 2 cables complete with springs; as they won’t be seen I used the easy option of brass tube as crimps, with a drop of cyano just to be sure.
I fitted the cables through the fuselage before threading them through the tubes built into the tail plane, one spring each side.
I then attached the cables to the control horns ensuring that there was equal tension in each cable by the simple measure of ensuring that each elevator was at the same relative angle. There is a little friction introduced by the pulleys and the springs running inside the tubes but definitely not excessive, as I’m using a separate servo for each elevator I’m certain there’ll be no problems.
Just the acetate “windows” and frayed tapes to fit now.
Apparently when I said in my last post “ensuring that there was equal tension in each cable by the simple measure of ensuring that each elevator was at the same relative angle” it didn’t mean much; I knew what I was talking about but of course I’d done it! Rather than just explaining the tensioning bit I thought I might as well do a step-by-step account of the elevator set up. If you’re building an SE5a, or similar and want to incorporate the pulleys etc., or you’re a bit “nerdy” like me and like reading technical stuff then the next few paragraphs may be worth reading. Then again you might just be suffering from insomnia and what boring to sleep!
The cables each consist of a spring with “tails” attached to both ends. A short “tail” that is attached to the control horn on the same side as the spring, which I’ll call the sprung cable. A long “tail” that passes through the fuselage and attaches to the other control horn; I’ll call this the non-sprung cable although of course the spring does have exactly the same effect on it.
My original idea was to pass the non-sprung cable through the centre of the spring of the other cable but in practice this wasn’t a good idea. When some tension was applied to the spring and the coils opened slightly the non-sprung cable could get between the coils and this caused a lot of friction; running the cable on the outside of the spring, between it and the tube in the tail plane, caused no problems.
I threaded the cables through the 2 halves of the tail plane bringing the sprung cables out for the top control horns and the non-sprung cables out for the bottom control horns. The choice was purely arbitrary but if done the other way round the following steps would have to be reversed.
The model was turned upside down and the non-sprung cable pulled until the spring hit the fuselage side. With full up elevator (remember the model is upside down) I bent the cable back on itself ¼" past where it met the control horn thus ensuring that in practice the spring would never hit the fuselage side. The cable was threaded through the control horn and fixed by binding with thin copper wire and a drop of cyano. This was then repeated for the other side.
The model was then turned the right way up and the elevators temporarily joined by a length of spruce and clamps. One of the sprung cables was threaded through its control horn and pulled until there was sufficient tension to keep the cable tight and provide enough friction on the pulleys to make them rotate when the elevator was moved from full up to full down. This turned out to also be about ¼" but I tensioned it just that bit more to be on the safe side and then terminated the cable as before.
When I removed the spruce “joiner” the spring contracted and I had one elevator deflected up and the other deflected down.
Now we get the "equal tension" bit! I threaded the other sprung cable through its control horn and tensioned it until both elevators were in line. When operating the elevators together there’s no pulling against the springs as the tension of one counteracts the tension from the other.
I used canopy glue to attach the acetate “windows” and then added the frayed tapes. They’ll be painted once the inspection “windows” in the wings and the aileron connecting wires are in place and taped.
I’ve bolted the fin to the fuselage and added the tail plane support wires; they should be solid wires but I decided to use fishing trace because it would make life easier if / when I have to alter the incidence of the tail plane. I don’t know what it is but they just don’t look right, so much so that they’ll have to be changed, if it means more trouble later on I’ll just have to live with it; I think I’ll get some 24swg piano wire and hope that looks better.
It’s been quite a busy week but not a lot to show for it on the modelling front; to start with on Sunday I got my second “badge of office” as an official wrinkly, the first was my bus pass and now I’m a Granddad! Between the cooing I managed to get a bit of time down the shed and threaded the aileron control cables. I’ve tested the top ailerons and they work fine, but of course they’re the easy ones, I’m hoping to test the bottom wings and also connect the top and bottom ailerons tomorrow.
One thing I’m pleased with is the control horns, this is the first time I’ve had them “operational” and I have to say I think they look good.
In the neutral position the shackles are inline with the cables, it’s only when the ailerons are deflected that it shows that the shackles aren’t actually free to pivot. Of course the ailerons will be at neutral when the model is being “examined” and if anyone can see the shackles when the model is flying they’re a better man than me!
I’ve said before that I like to get the positions for the radio gear sorted out as early as possible in the build so as not to get any nasty surprises at a later stage, after all the whole purpose of the exercise is to produce a radio controlled model! Unfortunately, although I confirmed the principle for the aileron control very early on in the build, the practicalities of actually fitting it into the model could not be worked out then because I had no idea how much spring tension would be needed or how much “slack” the system would have.
This is the design that I tested to prove the principle.
I fitted the spring temporarily using the inserts from an electrical connector strip and adjusted the tension as necessary. Because of the tension I had to reduce the length of the cable joining the top ailerons slightly then all worked nicely.
I was surprised to find that as with the elevators there was no noticeable tightening or loosening of the cables and the tension required was the same, ¼" plus a bit for safety; I’d expected to have to use about double as the one cable controls all 4 ailerons, runs round 4 pulleys and there is a lot more of it.
Fitting the spring the way I have done has given me an idea; I’m going to turn the design “inside out”, that is I’m going to attach the spring outside the servo arms not between them as originally intended. Doing it this way means I’ll be able to move the servos a lot closer together, which will mean less bending of the snake inners, which in turn will make for a smoother and more precise movement of the ailerons.
Having got to this stage I couldn’t resist the temptation to fit the wheels and take a couple of photos.
Looks a bit “naked” without all the wires, Lewis gun and a pilot!
The wings are now joined together and I’m very glad to say that it’s no problem attaching them to the fuselage; if it had turned out to be not viable to disassemble the model for storage in the shed I would have had a lot of grovelling to do to the better half!
I had thought that the wings would be quite “wobbly” when held in the frame but in fact the assembly holds itself in position quite well. The photo also gives a good view of the underside weathering and the inspection “window”.
The interplane struts are held in position with bent pins with only the bent section epoxied to the strut; if needs be it should be fairly simple to remove them. The struts only really need the pins to hold them in place until the model is assembled, after that the struts are always in compression so they really hold themselves in position on the pegs.
The front flying wires are permanently attached to the fuselage bracket; the 2mm stud goes through a hole in the fuselage side just above the front undercarriage leg and is held tight by a nyloc nut.
On the full size the rear flying wires are attached to the fuselage inside the lower wing stubs. This is impractical on a model of this size so these wires end inside the wing stubs joined by a length of brass tube.
The SE5a has a very thin wing section but the model has sufficient strength, thanks to carbon fibre spars and LE, to not actually need flying wires, except for show, so it is perfectly feasible to just leave the wires loose. I don’t really like that idea though as I feel they might “flap about” uncontrollably once the engine is running so I’ll devise a way of applying at least some tension; either flexible “tails” attached to the wires themselves or hooks on flexible wires inside the wing stubs, I’ve not decided as yet.
For the last few days I’ve been experimenting trying to make the tail plane support wires from 24swg piano wire. I made various ends using brass and aluminium tube but none of them looked right; they were all too “chunky”. In the end I decided to try bending the wire to the exact length required, doing this meant there would only be 2 wires in the “ferrule”, which could also be a lot shorter as it isn’t functional. This was not my preferred method as I thought it would be a problem getting the bends in exactly the right place but as it turned out it wasn’t too difficult, of the 8 wires only 1 had to be scrapped and re made. The ends are made from a sort length of heat shrink tubing, which is very thin walled, painted silver; they still need to be “dirtied up” a bit but the overall effect is certainly a lot better than the fishing trace.
When assembling the model I have to connect the 4 aileron cable quick links, this is a bit awkward as there is only a relatively small gap between the centre section and the wing root rib. To make things easier I’ve made a small “ tool” to hold the links open, as a bonus it also stops the links disappearing into the wing tubes!
It is simply inserted into the link and turned through 45º. It’s easier to see how it works using a link that is not on the model.
The aileron linkage is now fully installed in the model and it all works fine! I still need to tidy things up a bit; I need to make new servo connectors because as I was fitting everything into the model I realised that once they’re glued into the snakes the servos would be very difficult to remove and knowing my luck one of them would pack up, I’ll also make better spring connectors,
Because I decided to modify the servo linkage by “turning it inside out” so to speak I was able to mount servos horizontally instead of vertically as I’d originally intended, which makes things a lot easier. The mounting plate is from 0.5mm galvanised steel with some 1/8th ply to improve the grip of the mounting screws.
I modified the mounting lugs to enable both servos to be held by the same grommets, this wasn’t strictly necessary but the assembly being that bit narrower does make it easier to fit into the fuselage. 2mm mounting studs are glued into some 1/8th spruce, which also helps to keep things straight.
The whole assembly fits between the front spars and is held in place by the 2 studs.
This photo is at neutral.
As the servos move, differential ensures they don’t work against each other whilst the spring keeps the cables under tension; only the “pull” servo is doing any work.
As each aileron servo has to operate all 4 ailerons with their associated cables and pulleys I needed “high torque” servos. Because I wasn’t convinced that the system would actually work satisfactorily when installed in the model and I didn’t want to waste money, I decided to buy a pair of “cheap” Supertec servos.
These are very powerful, giving 7.4 kg/cm torque at 4.8volts and have no trouble at all moving the ailerons, but they do sound a bit “agricultural”. I now think maybe I should have had the “courage of my convictions” and gone for either Futaba or JR. Can I now justify the extra expense?
To answer the rhetorical question posed at the end of my last post; “yes I can!” In fact having given it some consideration I changed the question I asked myself to “having spent the best part of 2 years building this model can I afford not to buy better servos?”
I’ve bought a pair of Futaba S3305, they have slightly less torque at 7.1 Kg/cm but are quicker, 0.25 sec/60º as opposed to 0.33sec for the SuperTec; I’d thought that the 0.11 sec that the SuperTec were slower than “standard” wouldn’t really be noticeable but it certainly was and importantly the Futaba don’t have that “agricultural” sound. I’m a lot happier with them notwithstanding the extra cost!
I’ve also replaced the 148s with ball raced S3001Bs.
In order to rig and connect the aileron cables to the servos the model has to be held upside down; before I fitted the Lewis gun I just used beanbags for support and protection but obviously this was not a permanent solution so I've made a stand.
The stand is a length of 75mm x 50mm timber and “Y” shapes soldered up from15mm copper pipe with foam insulation for protection.
The stand will also come in handy for routine maintenance etc. as it holds the model securely whichever way up it is!
there’s at least another 3 months of winter to get through before I even think about that, then I like to get my thumbs coordinated with my brain again using the AcroWot. As for some “walk around” shots, I think that’ll have to wait for better weather; the front room is big enough so just maybe, once the Christmas decorations are out of the way, and if I grovel enough you never know your luck.
The model is now all but finished; the “teething troubles” with the rigging has been sorted out by using a mechanical tensioner to keep the cables in the pulleys at all times. The problem is that there is not much room between the wing and the centre section whilst rigging, this taxed the brain a bit until I literally used some “lateral thinking” and although I’ve only used it a couple of times I don’t envisage any more problems.
This is obviously just the prototype; when I make the rest of the set they’ll use springs not elastic bands! It doesn’t need much tension, in fact the elastic band is really too strong.
When in the storage position the ailerons are at neutral and the quick links just protrude from the wing tubes.
When connecting an aileron cable it is pulled out from the wing tube, which of course pulls the other connector into its wing tube, the metal “staple” is to stop the thread cutting into the rib.
As I said in my last post, the model is all but finished and there’s a long time to go until the flying season, so the question is what to do in the meantime? Reading through Steve’s build thread on RC Universe this photo of his SE5a got me thinking; a Cooper bomb rack would while away the hours!
I was a bit concerned that my SE5a was “piling on the pounds” with all the detailing work so I contacted Steve to ask what his weighs as it obviously flies very well. A quick calculation for relative sizes gave me a target weight of 4.2Kg, so I stood on the scales holding the model with my pockets full of batteries, servos and a Laser 70 and got a weight of 3.8Kg. The model actually feels quite heavy but there’s a lot of wing area so I’m sure the model can take the extra weight, but whether or not I manage to sort out the complexities of designing and building the bomb rack remains to be seen!
At last I’ve made a start on the bomb rack, or to be accurate on the bombs; there’s no point making a bomb rack if I can’t make the bombs! Here’s a photo to show what I’m aiming for. (sorry, I just couldn’t stop myself!!)
I decided that the only practical method is to turn the bombs, but therein lays the first problem; I’ve not got a lathe. If you work for Health and Safety I suggest you don’t read the next bit. I "converted" my vertical drill stand into a make shift lathe, very Heath Robinson but it works.
I started with a length of curtain pole and I’ve now got the basis for one bomb, but I don’t think I would be able to produce all 4 bombs and end up with them all being the same; they’re quite a complex shape.
I’m thinking of using this one as a master for a mould and then making a set of bombs from casting resin. I’ve never used casting resin before so any tips / advice will be gratefully received.
One question that immediately springs to mind is “is it tuff enough to withstand being dropped from the model?” They will be released quite low, I’d think about 50ft and at relatively slow speed over grass. For safety I intend to mould the front black bit from rubber and the arming vanes will be removed.
There was no chance of getting any casting resin until after the Christmas holidays and as Steve successfully turned his 4 bombs I thought I might as well give it go.
I’d turned the first one using a card template and found it quite a difficult and slow job; then I had a “eureka” moment, it does happen! I measured the diameters at various points along the length of the bomb, turned the wood as a series of cylinders and then simply tapered from one diameter to the next.
This produced the other 3 bombs very easily and quickly; just as Steve said, “ they’re not factory perfect” but certainly near enough for me and a lot cheaper than buying casting resin etc.
Making the bombs as a series of cylinders was simple and quick, which is just as well because I’ve had the make a completely new set of bombs. It wasn’t until I came to fit the rear fins that I realised that the rear section of the bombs was about ¼" too short. It just goes to once again emphasise the old adage “measure twice cut once”!
So what went wrong?
I first tried to turn the bomb using a single template of the wood to be removed, this meant that before the template for the widest part of the bomb got close to the surface the deepest cuts had to be made and this made the work piece quite weak and impossible to work with safely. I decided to “split” the bomb into 3 sections; I made templates for the front and middle sections, the rear section is just a straight taper so didn’t need a template. To ensure that the curves “flowed” nicely I decided to make the templates overlap by a ¼" but somewhere I got the measurements wrong! Having turned the front and middle sections I simply measured the overall length of the bomb and tapered the rear section accordingly not realising that the front of the bomb was in fact ¼" too long. When I decided to turn the other 3 bombs I used the master, not the photo, to set the callipers and measure the distances so duplicating the error. When I discovered the error I remounted a bomb in the lathe and tried to correct it but that didn’t work at all so 4 new bombs it had to be. It’s not all doom and gloom though; at least I now have some “spare” bombs to practice on.
I found that cutting 2 slots as a cross to fit the fins made the rear section very fragile and I was afraid that I might break the “legs”, so I cut one slot first, glued in opposing fins made from a single piece of 1/64th ply, then cut the other slot and fitted the other 2 fins once again as a single piece.
The bombs have been filled and sanded but I’m not too concerned about a perfect finish, after all if everything goes to plan they will be dropped from a great height and are certain to sustain damage or even get lost in the grass!
I turned a plug for the nose of the bombs from which I hope to make a mould to produce them in rubber.
The decision to add the bombs was only taken recently after seeing the photo of Steve’s model; I’ve done very little research on the subject myself. I’m using information supplied by Steve; if it’s good enough for him then it’s good enough for me!
I’ve no idea what the loop at the back is for but I do have some general information:
The SE5a was developed well after the time of dropping hand grenades or bombs by hand from the cockpit or shooting at the enemy with a pistol. The load it could carry was limited so 4 bombs of 20lbs each was the maximum, either as 2 sets of 2 bombs, one under each wing or a rack of 4 under the fuselage just aft of the undercarriage legs. The bomb release, operated by the pilot, is the out of focus black lever mounted low down on the cockpit side.
Pulling it back released a bomb, pushing it forwards reset the ratchet system, pulling it back again released the next bomb and so on until all 4 bombs had been dropped.
This is a compilation of posts “lost” because of the hacker attack
I intended to make a mould for the nose section from Plaster of Paris but a trip to our local chemists drew a blank; they even tried to order some from their supplier with no luck. During a recent decorating episode, which involved a fair amount of repair work to the walls in preparation for emulsion painting, we used Polyfiller, it seemed very similar to Plaster of Paris so thought I’d try it.
The plug was prepared by dripping molten candle wax all over it, heating it up with a hot air gun re-melts the wax and most of it drips off leaving a very thin layer. I mounted it on a plastic base with a wall of Plasticine and then gave the lot a spray with WD40.
The Polyfiller was mixed quite thin and carefully poured in to fill the mould. It’s not as quick setting as Plaster of Paris; it took about 2 hours to harden and be ready to remove the Plasticine and the base, then another couple more to dry before carefully easing out the plug.
It has actually turned out surprisingly well; there are a few places where the Polyfiller has broken away in between the lugs but to be honest I expected a lot worse. It remains to be seen whether or not I can use the mould to produce acceptable rubber nose sections; I still have my doubts.
There was a reply from Alan2525 about the type of rubber
I have not idea what sort of rubber I’ve used; I bought it years ago from the model shop, I think its intended use was for making moulds for casting Plaster of Paris figurines. It’s very soft with a “natural” colour; you melt it over a low heat then pour it either into a mould or over a plug dependant upon whether you’re making a male or female item, and then just let it cool and set.
Being thermo-plastic it was easy to “touch up” the mouldings using a precision screwdriver heated over a candle flame. They’ve been glued to a 1/64th ply base with cyano and given a coat of black paint.
The finished parts are not perfect but I’m not going to too much trouble as they are “throw away” parts and as such will be attached to the bombs with double-sided tape for easy replacement, I’m sure they will need replacing after just a few “bombing runs”. I might make a set of better finished parts for static display.
The bomb release mechanism on the SE5a is very complex, no surprise there then! Although of course it is a proven design there is no way I could duplicate it in miniature so I’ve had to design from scratch
Steve used 4 different length pins to hold the bombs, being a control line model he was able to use a 5-way switch to control the release mechanism but I only have either the retract channel or, if I invest in a new 8 channel receiver, a proportional channel. A proportional channel would be the easiest to work with but I don’t like the idea, if I turned the knob a bit too far a bomb might almost but not completely release then with vibration it could release itself at an unplanned time, which could be dangerous, or at the very least loose me a bomb.
I will use Steve’s idea of different length pins and having decided that the “bang / bang” retract channel it will be, I need some way of “stepping” the release mechanism. I got my thinking cap on and came up with an idea inspired by the timing gear in a clock. I made a mock-up to see if it would work in practice.
The main release bar has 5 indexing pins spaced at 5mm intervals and will eventually have 4 bomb release pins each 5mm longer than the previous.
The release cam has a slot cut out from the centre; before an indexing pin is released from one end plate by passing through the slot the other end plate is in a position to "catch" the next indexing pin.
This is a series of photos showing the sequence as the servo moves the release cam arm backwards and forwards from one extreme to the other; the release bar steps by 5mm with each operation.
At the moment I’m using an elastic band, the spring tension will need to be worked out when it is actually releasing bombs, I hope!
Before I could start on the bomb rack itself I had to finish off that most useful of Christmas presents, a family size tin of Quality Street; for those who haven’t realised these tins also provide a good supply of flat tinplate. As a special favour, to help the better half keep to her new year’s resolution to watch her diet, I volunteered to take on the task myself!
The main body is made from the tinplate with a brass tube for the rear support. The release arm is made from 2mm threaded rod, the threaded section acts as the bearing in a length of tapped snake inner cyanoed in a brass tube. It will extend up into the fuselage through the large opening just behind the undercarriage legs to connect to the servo.
The release mechanism works a lot better now that a bearing supports the release arm.
The bombs are now finished, not without a few problems along the way!
I painted the rubber nose sections with Warbirds paint; I thought it would be OK because it is water based although it does have a couple of drops of a catalyst added to make it fuel proof, but it turned sticky after a few hours so obvious there was some reaction. I stripped the paint off but the rubber was still sticky, I’d got nothing to loose so I tried the old “trick” of dusting them with talcum powder, this time I painted them with “genuine” acrylic and there was no problem, I dusted them again, just to be sure, before the second coat.
I’d intended to attach the nose sections with double-sided tape for easy replacement but this also didn’t work very well so they are now epoxied in place.
The arming vanes are from tinplate soldered to a pin so these are easily removable.
They will be removed before dropping the bombs because not only could they cause damage they would also be damaged themselves.
Even this simplified bomb rack is quite complex and it still has the safety stops to be added.
I mounted the bomb rack on some scrap balsa whilst I adjusted the bomb cradles. This adjustment turned out to be quite critical; a balance between having the bombs loose and able to swing about or too tight to allow the release bar to move under the spring tension.
In fact it was so critical that I have had to number the bombs to ensure they are fitted in the same positions, the slight variations in the diameters of the bombs where the cradles support them was enough to cause problems.
The bombs are held in position by different length pins that pass through loops on the bombs, which themselves pass through slots in the base of the bomb rack. This photo was taken before any adjustments were made; the bombs are now equally spaced!
The bombs are loaded in the reverse of the order that they are released. With all the bombs released the release bar projects 20mm from the end of the bomb rack, I don’t think this will be too obvious “in flight” but if it is I’ll shorten the release bar and extend it with a length of piano wire. The first bomb is held in position and the release bar pushed in to engage the release pin through the bomb’s loop, the slot in the release cam is such that the previous indexing pin can pass back through it when the release bar is pushed in. The cam is then moved (at the moment by hand but once on the model by flicking the retract switch on the transmitter) to the other position. The release bar can then be allowed to spring back against the cam whilst the next bomb is put into position and the process repeated until all 4 bombs are in position.
The bomb rack is bolted to 4 small brackets fitted between the undercarriage legs; the release arm has a ball-joint soldered to it just inside the fuselage bottom and the control rod passes forwards between the undercarriage cross members and the fuselage bottom.
A mini servo to operate the bomb release is located in the engine compartment attached to the firewall by an “L” shaped servo mount.
Commercial “L” servo mounts seem to me to be very expensive for what they are so I make my own from “L” shaped plastic extrusion from B&Q; I bought a 6ft length for a couple of quid years ago and I’ve still got half of it left!
Something I’ve never done before is to make a “static” prop, after all the object is to end up with a flying model not a static display, but as I’ve got time on my hands I thought I might as well give it a go. An added incentive is the fact that I’ll be using a 13" or 14" prop for flying whereas the scale diameter is 18¼" so the flying prop does look very small.
As I said I’ve never done this before so it’ll be a case of trail and error and hope for the best; to make things easier I decided to go for a 2 bladed prop. I thought of making it laminated but it would be quite costly to buy the wood and as I’m not certain of the outcome I decided against it. From a front view photo I produced a template, glued it to a piece of knot-free pine and cut it out with a jigsaw.
I was very surprised that it only took about an hours work with a plane and a rasp to produce a reasonable looking prop, and a large pile of wood shaving!
A working prop is in a completely different league from the one I’m making; a static prop just has to look right, it doesn’t have to produce thrust or withstand any of the forces that implies. I certainly wouldn’t want to trust my prop to fly the SE5a!
The prop blades have been thinned down considerably, initially using the Dremmel but finishing off by hand. One coat of stain has been applied, several more to go.
The props had various things done to them and as I have no evidence as to what, if anything, was done to the prop of E5808 I can choose the variant I like best.
The choices I know about are:
1. Metal reinforced leading edges.
2. Metal reinforced tips.
3. Both of the above.
4. Outer half of blades fabric covered.
5. Blades bound with several turns of cord about mid point.
6. Plain stained wood with no additions.
At the moment my preferences are 1 or 5, I’ll probably try litho plate for reinforced leading edges first, if that doesn’t work I’ll go for the binding.
I’ve got the easy bits out of the way first; it certainly looks better than the “standard” Laser prop nut.
For flying I normally use a 13" prop with a 6" pitch, but having seen how much better the model looks with a bigger prop I’ve been thinking, if the pitch was reduced to 4" then the diameter could be increased to 15" or 16". This has the advantage of increased static thrust, which is useful for overcoming drag, also the model will fly slower for any given revs so the engine can be tuned for maximum power without having to fly like a pylon racer.
Searching through the catalogues I found that APC do make a 16" x 4", the downside being that it is about 3 times the price of a 13" x 6"; do the looks really matter that much?
I thought that getting the litho plate to bend around the prop blade following the curved leading edge would be a problem; one reason why I got the hub etc. done first! As it turned out it was no problem at all, the most awkward thing to do was embossing the rivets as this had to be done last of all and it was quite tight to get the embossing wheel in. To make the job easier I “opened out” the litho plate somewhat then carefully refitted it to the prop blades using just my fingers and a cloth to ensure none of the rivets got flattened.
Of course it all looks very shiny and ex-works at the moment, a bit of weathering will soon change that.
I have to say that I’ve thoroughly enjoyed the last few days making the static prop; obviously it won’t improve the model as a flying model but all in all I think it’s been worth it, hope you agree.
Well I think now is the time to change the title of this thread by substituting “END” for the last 3 dots. I still have to fit the fuel tank and the radio gear, but I don’t think this really constitutes “CONSTRUCTION”. There are still some small bits of detailing to do but nothing significant, I’ll post photos if I think they’ll be of interest.
I moved the settee and took a few photos against a plain wall, which hopefully shows up the detailing more clearly; when the better weather arrives I’ll take some “al fresco” for a more realistic effect before I risk the first flight!
I’d like to thank everyone who took the trouble to post a reply, be it either help, suggestions or just words of encouragement; with special thanks to Giles for the research material, Christian for the photos and Steve for the inspiration and help with the Cooper bomb rack!
To clarify things, when I said "now is the time to change the title of this thread by substituting "END" for the last 3 dots" I meant I’ve finished the construction section of the thread, not that the thread itself has come to the end. From now on, as well as the more mundane task of actually fitting out the model ready for flight, I’ll be adding / improving some of the detailing that I didn’t bother with earlier. Then of course there’s the flying!
The Lewis gun is very prominent, mounted as it is on top of the wing, so I thought that the magazine strap, which I’d made from masking tape, let the job down a bit. I still had some of the "thinned down" leather I’d used to make the cockpit edging so I decided to make a leather strap, complete with brass buckle.
The buckle was very easy to solder up from thin brass rod, but I think it really finishes the job off and was well worth the little time and effort it took. It was so easy in fact that I did the same thing to the "spare" magazine, which is just about visible through the fuselage window if you look very carefully.
I’ve added a bit of “bolt head” detailing to the wings but nothing of note, however, a couple of other things may be of interest.
I attached "looped" tails to the rear flying wires that thread easily through the lower wing stubs and into the fuselage; these are pulled tight and held by a pair of aluminium clamps. When prepared for flying the tails will be positioned down the side of the servos to ensure that they can’t snag the elevator or rudder controls.
With all the flying wires under tension the wings no longer need the grub screws, which lock onto the wing pins, to hold them securely to the centre sections, but a bit of extra security never goes amiss so I’ll still use them!
One major drawback of having a fully enclosed engine is that regular checking / maintenance is awkward and the temptation is to stretch the times between checks. For this reason it is important to make sure that the fuel tubing can’t slip off the tank tubes etc. and the best way I’ve found to do this is to solder a ring of thin wire around the ends of the brass tubes.
To make doubly sure a commercially available fuel tube clip can also be used but I haven’t found this necessary in the past.
The “plumbing” on most scale models is somewhat more involved than on sports models; with the engine being fully enclosed it’s not easy to get at the fuel pipes and we don’t what to have erroneous holes in the cowl or pipes protruding where they shouldn’t.
My preferred method is to have the filler pipe going to the bottom of the tank so that it can also be used to empty the tank, this means that to prevent the fuel siphoning from the tank the filler pipe has to exit the fuselage somewhere above the top of the tank and my original intention was to use the radiator cap to hide the filler pipe. This idea was abandoned because it would have made the fitting and / or removal of the cowl very awkward, other openings also presented problems and I was beginning to think that I’d have to resort to removing the cowl for filling and emptying the tank.
The answer was in fact blindingly obvious; it just took me a long time to see it!
The top of the tank becomes the bottom of the tank when the model is upside down and, as I have to invert the model to de-rig it, I simply have to wait until that time to empty the tank. The filler and vent pipes both go to the top of the tank and are accessed through the prop shaft opening just below the crankcase
Both pipes face forwards to provide slight positive pressure in the fuel tank and are set back somewhat into the fuselage so will be very unobtrusive.
I’ve not as yet decided how I’m going to do the exhaust. The standard silencer fits inside the cowl, of course the outlet will have to be extended to exit the fuselage via one of the many holes in the bottom pan but I’ve had problems with silicone exhaust tube in the past with my Parnall Elf.
To be fair the silicone exhaust tube in that case was fitted between the engine and the silencer so had to deal with more pressure and a higher temperature than normal
Or I could use flexi pipe to a custom silencer mounted under the engine plate similar to the method I eventually used for the Parnall Elf.
Obviously using the standard silencer is the easier option but it might be “spoiling the ship” etc.; I’ll see.
The tank has been sealed to the firewall using “bathroom” silicone sealant to ensure no fuel / oil gets into the fuselage innards; when I came to seal the tank in place I realised that had in fact prepared the wrong tank (see the photo in my previous post!)
I bought the stainless steel flexi exhaust pipe direct from Laser Engines but I understand that they have had problems with the quality and recently stopped supplying it. Whether or not they’ve managed to sort out the problems I don’t know but it’s worth giving them a ring, I’ll certainly ask when I order my new engine later this week. Otherwise DB Sport and Scale sell some but what the size is like to fit Laser engines I don’t know but I’m sure they will!
If at all practical I do prefer to use the standard silencer rather than make my own because the manufacturer has tested it so you can be sure it will work as an efficient silencer and also won’t have a detrimental effect on the engine’s performance.
The standard silencer fits OK inside the cowl but extending the outlet is not straightforward as it involves a tight 90º bend which could cause a heat / pressure build up and possible failure of the silicone tube.
To eliminate this bend I’ve made a 90º connector using standard copper pipe fittings silver soldered together; a 15mm Tee and 15mm to 10mm Fitting Reducer. I’ve removed as much copper as possible from both fittings in order to save weight and sealed a one end of the Tee with a flat plate. I used a “solder ring” Fitting Reducer because the ring formed to hold the solder makes a nice lip, which will help to retain the silicone tube.
By good fortune the silicone tube is just the right size to form a flexible, gas tight seal when the connector is pushed onto the silencer outlet. Thanks to Alan I can tell you that the silicone tube is exactly 15mm plus a gnats whisker less than a smidgen!
I’ll extend the connector with either a short length of silicone tube then flexible stainless steel or silicone tube all the way to the exit.
I’ll soon be ordering a new Laser 70 for the SE5a so I’ll use the running in period as an opportunity to thoroughly test the system before committing it to the model.
The exit pipe once again uses a 10mm copper pipefitting and in this case also some 10mm brass tube; all silver soldered. The exhaust will exit via 2 of the holes in the engine under pan, not the scale exit points but at least I’ll have 2 exhaust trails following the model.
The complete exhaust system.
I ordered a new Laser 70 today so it shouldn’t be too long before I can start to test everything. If all is OK then I’ll trim the ends of the exit pipe to be inline with the under pan when attached to the model so in practice they will not be seen.
If the system isn’t satisfactory then it’s back to the drawing board!
My new Laser 70 has arrived and of course it ran flawlessly after starting “first flick”, not that you’d expect anything less from a Laser. I should point out at this juncture that I have no commercial interest in Laser engines; it’s just that they are such good engines that I can’t stop “singing their praises”!
Although the excuse for getting this new engine is the SE5a, in fact I’ll use one of my older, well run, engines. This one will free up one of my other Lasers by being mounted in the AcroWot and have a good few flights, first without the cowl to ensure really efficient cooling then after a couple of hours flying time with the cowl fitted. A fully enclosed installation such as the SE5a isn’t the place to bed-in a new engine.
I have modified the crankcase breather on all my Lasers to make it easier if the engine is mounted close to the firewall. A short length of brass tube is soldered to the nipple; without it the fuel tubing extension would have to make a sharp 90º bend, which has a tendency either split of restrict the breather.
I make it a “T” so it’s just as good if the engine is upright or inverted, the extension tube is fitted to the appropriate side and the other is blocked off.
I ran the engine both with and without the SE5a exhaust extension and the only difference I could tell was that the exhaust note sounded a bit quieter with the extension fitted. One thing that I did find out was that I’ll have to incorporate some form of strap because when I opened the throttle above about half way it blew the extension off. Before I do any more testing I’ll run a few tanks of fuel through the engine to get it settled down and fit the strap.
For the next tests I will get more “scientific” results on the effect of extending the exhaust by using a rev. counter, which I don’t own, but I know a man who does!
Although I’ve not yet done any “scientific” tests, I should be getting a loan of a rev. counter next week, I have carried on with the installation of the exhaust.
Having run the engine both with and without the exhaust extension I applied my usual method of decision making; if it looks / feels / sounds OK then it most probably is OK! (apologies to Peter).
I silver soldered mounting brackets to the exhaust and squashed the ends of the pipes somewhat to fit through the holes in the under pan. 2 hardwood blocks epoxied to the fuselage sides to screw into completed the installation.
I trimmed the pipes so that with the under pan fitted the exhaust doesn’t protrude and isn’t visible when viewing the model normally.
I said in my last post “A fully enclosed installation such as the SE5a isn’t the place to bed-in a new engine “. Of course it isn’t ideal for any air-cooled engine new or old so extra care has to be taken to prevent over heating; the full sized was water-cooled. To explain how I hope I’ve overcome the problem I’ve used some old photos as well as a couple of new ones.
The SE5a has some positive points; there is a hole directly in front of the cylinder head for cooling air to enter.
And there is a large opening in the fuselage behind the engine for heated air to escape.
However, things are not as straightforward as they seem; hot air wants to rise but the exit hole is in the bottom of the fuselage. Once the model is moving forwards the air flowing over the hole should produce a venturi effect and suck the hot air out, but this is where the SE5a designers throw another spanner in the works!
Below the engine shaft there is an even bigger air entry hole, air entering here will not help with the cooling but will have the effect of “pressurising” the bottom half of the engine compartment and restricting the outflow of hot air.
The easiest solution would be to mount the engine inverted but because of the position of the engine shaft this would mean either a much larger model or the cylinder head sticking out the bottom of the fuselage, so this is a non-starter.
The engine plate has a hole corresponding to the one in the fuselage, so the hot air can transfer to the bottom half of the engine compartment.
A template, this is where you’re glad you paid attention in all those geometry lessons, is drawn and stuck to litho plate.
When cut out and bent up it produces an air scoop that forces air entering below the engine shaft upwards into the top half of the engine compartment where it can help to cool the engine.
Also with little or no pressurising of the bottom half of the engine compartment the venturi effect can work and suck out the hot air; a win / win situation!
There will be a short delay before I can fully test the exhaust.
We went down to Leicester over the weekend to visit my brother and as we got ready to leave I remembered that I wanted to borrow his rev. counter. Being super organised he knew exactly where it was so went to get it, his super organisation being as good as mine when he looked where he “knew” it was it wasn’t there! Sound familiar? He found it soon after we’d left and as he‘s coming “up north” in a couple of weeks for the TMFC Bring a Model Night we can do the tests then.
I’ve made a clamp to stop the extension being blown off the silencer; it’s similar in concept to the Laser carburettor and exhaust clamps.
It’s made from tin plate and I’ve used soft (lead) solder. I don’t think it will get hot enough to melt the solder but even if it does it won’t matter because once it’s clamped in position it holds itself together.
I’ll use a cable tie around the silicone tube.
There will be yet another delay before I can test the exhaust! My brother had intended to visit for the Teesside MFC Bring a Model Night and bring his rev counter with him, unfortunately he got the dreaded lurgy so couldn’t come.
Although I was feeling pretty rough myself I took the SE5a along; the lighting in the room left something to be desired to say the least and several people commented that it was very difficult to see the cockpit so I said I’d post a photo on the TMFC forum.
When I checked I found that I hadn’t in fact got a photo of the finished cockpit so I took one and thought I might as well post it on here as well!