Greyhead

Ducan

The varnish had plenty of drying time and it wasn't the water based variety.

To be fair to it the exhaust was quite powerful stuff, hot and mixed with the contents of the crankcase breather as you'll see later in the thread. I just hope that the Tuffcoat copes better and the exhaust is now not as hot.

Grahame

Greyhead

It’s now time to fit the radio gear. One problem with closed loop or pull / pull systems is “hiding” the cables as they pass through the cockpit, one solution is to use a snake from the servo to a bell crank fitted behind the cockpit to which the cables are attached but in this case I decided to fit the rudder and elevator servos in the luggage compartment; it also makes them easy to get at to adjust. No worries about ending up tail heavy with a large lump of Laser up front. First a shot with the hatch closed; you can see that the fuselage is clearly made of wood as the grain is still slightly visible as it is on the full size and one of the magnets for the lower rear wing section.



Now with the hatch open, once again a magnet used to hold it shut. You can also see the neat edges to the lettering.



The aileron servos are mounted to the fuselage side with the arms protruding through slots to attach to the push rods and a mini servo under the cowl operates the throttle.

One problem I’ve had with all my previous “early” biplanes is their tendency to ground loop i.e. they veer off course when taking off, as it’s important to take off and land directly into wind with these models this results in a lot of aborted take offs. The problem can be rectified by widening the under carriage and moving the wheels forwards but then it’s not a scale model is it?

I’ve found the perfect answer, a “heading hold” gyro to control the rudder. With the model pointing into wind the gyro is activated, via a spare Tx channel, and so long as you can resist the temptation and keep your hands off the rudder stick the model will track straight down the runway.

Gryphin

Duncan
I only use water based Polyurethane varnish, to fuelproof the tank areas and inside the cowl and if needed the whole model,and have never had any problems, just paint it on, two coats 24hrs between both coats and then fly 24hrs later.

The only time I used Tuffcoat and it lifted the paint, so you pays ya money and ya takes ya choice.

As for klear (a blast from the past) used that 30 years ago the give a nice deep shine to me boots dont know what effect this will have on a model.

Phoenix

i have clear coat for my plane when i get it finished

duncan

Gryph, I had to use the old spit and buff on mine but that was a bit more than 30 years ago ! :-(

Greyhead

Where to hide the switch etc. is always a challenge!



But if there’s a convenient hatch why no use it?



My home made hinges proved not to be up to the job at this small size i.e. only 3 section to each hinge so had to be replaced. The easiest way was to use thin rubber strip.

Greyhead

The engine compartment is rather more crowded then I’d first envisaged, the plan had the nose section non-tapered, very similar to an SE5a, whereas it is tapered in plan, side and front elevations. The standard silencer just wouldn’t fit so I decided to just use a flexy pipe, about 6" long, attached to the scale outlet. Having talked to other Laser owners we thought that this would give sufficient silencing.



The bent pipe is for the crankcase breather, saves having an extra hole in the under pan and blasts the oily mess away from the fuselage.



This system worked well, up to a point!

Laser engines normally sound very realistic and although it wasn’t excessively noisy, to me it sounded a lot more like a single cylinder.

Without any expansion chamber the exhaust is hotter, I’m sure we’ve all suffered from “frozen finger” when operating spray cans for a prolonged time, as gasses expand they lose heat. The hot exhaust mixed with the breather output may explain the paint problems as it is directed onto the undercarriage.

I’ve now made a remote silencer from brass sheet.



I’ve only test run, not flown, the engine with this, it’s certainly a lot quieter, I think more so than with the standard silencer, I just hope that it cools the exhaust sufficiently and that the engine noise is back to it’s original realistic self!



The throttle linkage caused some headaches, with the carburettor angled it wasn’t an easy job until I thought of the idea of making the linkage run back into the fuselage first. The Bowden cable loops around the fuel tank and then back into the engine compartment, a bit messy but it works.

The bolt through the firewall is one of a pair, the other one in a similar place on the other side of the fuselage, which carry the current for the remote glow. They also help secure the firewall as they go through brackets bolted to ply fuselage doublers (see photo on page 1).

Greyhead

One thing I should have mentioned earlier is the spinner. The shape on earlier planes is not like most of our plastic spinners that are more akin to the WW2 period. The required profile (see reply 28 page 3) can be approximated by using just the front section of a standard two part plastic spinner. The rear section, that usually covers the prop, can have the flange removed or be discarded and a back plate made from aluminium. The front section then has to have cut outs to fit the prop and the screw support pillars will need reducing to clear the prop hub.

One problem I’ve not managed to solve is the aluminium finish; the electric starter soon makes a ring on the spinner. The best I’ve come up with so far is a coat of silver paint covered with a skin of epoxy resin, this lasts a few starts at least.

I know the easy answer is to flick start the engine, but as I suffer from tennis elbow, strange that as I’ve never played a serious game of tennis in my life, it isn’t practical in my case!

All suggestions / ideas gratefully received.

Greyhead

Now comes the worst bit of any build!

You’ve spent what feels like a goodly proportion of your adult life building this model, the radio and engine are fitted and working a treat and now you have to DO NOTHING!! Just sit and twiddle your thumbs as you wait for perfect weather, a nice warm, steady breeze to help keep the landing speed reasonable. I can’t understand people who, after investing all the time and effort into building a scale model, test fly it in blustery conditions; apart from the obvious higher risk of damage it is very difficult to make meaningful trim changes.

I place another restriction on myself for a maiden flight; I don’t try when the site is busy. I feel enough pressure without numerous eyes watching your every move and /or a crowded sky. The worst culprit is the club “expert” who will point out all the things where you’ve gone wrong and explains at length how he’s solved the problems.

Talking of the club “expert” prompts me to ask 2 questions:

1 Does every club have one or are we just “lucky”?

2 Has anyone actually seen any of the multitude of models he professes to own, not to say having seen him fly anything?

The next post will chronicle the first traumatic flight and the subsequent changes which, made over a few flights, have transformed the Elf from a “dog” to a “pussy cat”!

Bluewavestudios

Hi Grahame,

An Excellent model with clearly many hours put in on it & the workmanship shows it. I hope the Test flight goes well for you.

As for the Club "Expert", yes we all seem to get one of those crop up wherever you go. Not that I mind useful advice and tips, I am all ears then. I see some really sound ideas coming up on here all the time.
I have noticed the so called Experts round here always seem to have just the one and the same model everytime we go out......surely they must have more than that...???!!!!

This is regardless of whether it is Cars, Boats, Planes or Heli's....!!!

Regards.........Mark.