Tiger Moth

Since this is a semi scale model it won't be doing any fancy aerobatics, plus it's a fairly long tail moment so I'm going to stick with 9gm servos, but, I'm going to use some metal gear servos that I happen to have in stock.



I also noticed that one push rod tube hole is higher than the other, this is because the rudder rod exits from the top of the decking while the elevator exits from the fuselage side. I now notice that I have unerringly placed A7 the wrong way around! It's not a train smash since both sides and both top decks have exit holes cut in.

That decision made it's time to glue in A33 (spine), A13 (stern post) and A17 (tail plane platform)

OR just make the hole bigger to allow for a clevis

Time now to put in the strengtheners for the wing dowels.


Its number is A25, I've put the rearmost dowel in to hold them.


And A24, those people going electric will notice there is a gap under the side doubler which the IC version doesn't have on account of former P3 I would recommend cutting the ends off your P3 and using them as spacers, it will also add a bit of strength.

A32 and A5 can now go in, this completes the fuselage for now while I contemplate the tank position, thrust line and finalise the servo positions.

Bare fuselages tend to get damaged quite easily so at this point I normally put the wheels on, even if only temporarily. Which immediately threw up a problem.


OK, I know the Moth normally has a skid but we're building the kit as supplied. Only 1 suitably sized collet is supplied which is going to give us problems. Multiplex do it correctly.

Note a collet to stop the axle disappearing up into the hinge point and causing the rotation to seize and collets either side of the wheel to stop the wheel from rubbing against the vertical leg.
And now the words I hate to see in magazine print, 'I rummaged in my scrap box'!


This is how it should be.


A piece of scrap to bulk up the mounting point (shown in the instructions) but with some old servo screws to hold it since the supplied 3mm screws and nuts cannot be fitted, you can't get in there!

Now to the main wheels, same problem!


But in this instance 1 of the collets wasn't even drilled or tapped! Another rummage saw the axles correctly done.
The instructions a delightfully vague about the undercarriage position so I went with the pictures, and nearly drilled into the forward carbon wing dowel!


The saddles are a 'one size fits all' and the supplied screws seem to be overly long.


In fact once it's down tight it's just long enough.

When you consider all the trouble they go to to give the full size U/C quite a bit of suspension movement it does seem odd that in a model, which is likely to have much harder "arrivals", is given what appears to be a particularly 'solid' set up or am I missing something?

Much less mass and inertia ??

I'm trying to stick with what's supplied in the kit, but, at a later stage (after the maiden) I may take advantage of the fact that the main (forward) part protrudes out from the fuselage a little. It's crying out to have the saddles removed and some elastic put in to allow the undercarriage to rotate down and backwards a little.

I do very similar, but using 'school' erasers like Austin Mini springs. (Can't call them rubbers, our American cousins might misunderstand!) [badass]

Something else to watch out for with crumble-ply - this piece is quietly delaminating and curling up, and it has ONLY been inside! Luckily it is only a fuselage alignment jig piece, and has done it's job, so is of no further value.
I think the pale brown stains are the glue!

I suspect at 25% my humidity is a little less than yours! However I am seriously thinking of painting the whole thing with Polly C. I'll do the inside of the tank bay first and see what the weight penalty is.
I downloaded a 3 view to get an approximate thrust line since the hole in the A1/GP former is certainly not on the thrust line. Then it occurred to me to look at the electric version, bingo! The hole in the extension box is right on line, so I've built up the box and put it in the A1/EP so I can measure the thrust line exactly.

The 3 view shows the thrust line just on a level with the upper edge of the flat fuselage side.


Then I measured the thrust line from this.


I'm even more confused since this measured line seems to be 3mm lower than the top of the flat fuselage side. I think I'm going to go with the upper edge of the flat fuselage side, comments please.


The lower line is by measurement, the upper is where I think it might be.

Providing the thrust line is parallel to the fuz line, I don't think 3mm vertical offset will be critical.
You might find that at full power, the model wants to pitch up a little more, on the lower mark, so leave access for getting a few washers behind the mount, and in front of the firewall, for just in case down-thrust fiddle room. (teaching granny?) but how often will you BE flying at full power, apart from take-off, and maybe an overshoot?
As you put, earlier, you aren't going for 100% scale, or aerobatics.