Greyhead

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.

Full left



Full right



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?

Greyhead

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!

wonwinglo

Grahame is it really two years ? where did that time go to,but the fruits of your labours show beautifully in your latest picture here,it just says I want to fly and get some air under my wings !
That is a clever maintenance stand.

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Gaz

I love this thread! It's great to see things progressing.
A dumb question but where did the pilot come from? (or have I missed that part somehow?)

Greyhead

The pilot’s doing a bit of “moonlighting”, when he’s finished his day job fighting the Hun he jumps back into his Parnall Elf for a bit of relaxed flying!

A 1/6th “full body” from Pete Richardson (Pete’s Pilots), he now sells on ebay with what appears to be a drastically reduced range of pilots. I’ll have to email him to see if he does in fact still do “full body” pilots; they’re not shown on the web site.

I’ve had the wings on and off the fuselage several times sorting out the aileron linkage etc. with no problems, until today that is! The secret is to keep a small amount of tension in the cables whilst assembling the model, which I did by pulling on the linkage as I fed the wing pegs into their tubes, but I must have got a bit complacent today as one of the cables came off it’s pulley. After a considerable length of time and much cursing I managed to get it back onto it’s pulley using thin wire fed through the exit slot for the cable: I now have much more admiration for the “ship in a bottle” modellers! I’ll have to devise some sort of mechanical device to keep the tension; I wouldn’t want this to happen again as I’m getting ready to go to the flying field.

If you’ve enjoyed this thread then you’re in for a treat! Follow the link below for a build thread for a radio control / control line hybrid SE5a by Steve (smcouch77); the attention to detail is unbelievable; I just wish I’d known about this thread earlier.

http://www.rcuniverse.com/forum/m_50..._1/key_/tm.htm

Bluewavestudios

Grahame,

If you get stuck for a Pilot try A.H. Designs via the following Link:

http://www.thepilotpeople.co.uk/

He does a full range of Pilots including one which will be spot on for the SE5a.

I met the maker, Alan, a number of years ago now and have had a full tour of his workshops -He has some absolutely Fantastic Models and his Pilots are extremely Lightweight and well made too.

He lives just a Mile from my Parents House where he now has his workshops. (Alan can be seen on the Home page outside his house with one of his Kits he produces - The Extra 300)


Regards.......Mark

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I'm Only Here Coz I'm Not All There !!!

alan2525

Sorry for being impatient but - How long is it until the test flight and I'm sure a lot of the other members here are desperate for some walkaround shots of the aircraft in it's current state of completion! It's going to look beautiful in flight too. Can't wait for some in air shots too!

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Greyhead

Thanks for the link to AH Designs, I’ve never actually seen one of their pilots but I have to say they look good on the website. I won’t invest in a new pilot until after the first flight, I’m not superstitious but you never know I might not need one, it could end up in a binbag! Talking of the first flight, 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.

smcouch77

That's a very ingenious setup, Grahame. I think you would be safe to go ahead with the new pilot. This bird is going to fly great!
Steve

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Life's too short to fly ugly airplanes!

Greyhead

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!