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08-03-2009 | 11:27 AM

#15

NM2K

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From: Ringgold, GA

RE: LT-40 porker

Quote:

ORIGINAL: SeamusG

Things that I have learned ...
LT-40 is actually a 60-sized plane
LT-40's are notoriously tail heavy
LT-40 ARF will balance pretty nicely with an OS61FX (that's 13.6 oz heavier than an OS46LA) - em, I'm off by 14.5 oz)
Some people assume that the author of a thread has used a 5 lb sledge hammer when a tack hammer was needed
SIG tech support doesn't share much info

What will I do to proceed to ''maiden'' flight status?
Replace the engine with an Evo 52
Install a new longer mount
Replace 4-40 mounting bolts / blind nuts with 6-32
Replace 8 oz tank with larger tank
Most importantly - add a partridge in a pear tree (with lead weights as needed).

Btw, RC suggested doing a ''precovering'' assembly. I did just that. Everything (including Spektrum Tx, Rx programming) was installed & tested. What I didn't do was to ensure that this turkey was extremely ''nose heavy'' before covering. Not sure my ''to-do'' list would be any different because the plane's structure had been established.

Also, I don't subscribe to the ''if a little glue is good, a whole lotta gobbed on glue is better'' theory. If there is a known weakness, I try to figure out how to reinforce the structure before any glue flies. Just ask RC, sometimes what I come up with doesn't work the first time

and he has to fix it. Yea, we have plenty of club members who subscribe to the ''Gorilla glue it until you run out of glue'' theory. I'm not one of them.

Well, it's off to the store ...

I wouldn't go too much larger with the fuel tank. You can end up with a tank so large that your carb settings won't cover the range of head pressure adequately.

What you need is an Enya 60 or 80-4C four-stroke engine in the nose. Both swing a 13x6 briskly and both are a bit weighty. Other good engine choices would be an OS/Magnum .70/.91 four-stroke engine. Weighty and powerful enough.

I saw an LT-40 ARF fly at our field that was using an ST GS-40 engine. It was making the rounds quite briskly. I can't see where any more power was needed for training purposes.

Oh, one more thing. Someone said that the forward CG was for sport flying and the rearward CG was for training. This is just backwards from the way it really is. Rearward CG's make an airplane more maneuverable, but less stable. Stability is what is needed in a trainer.

Ed Cregger

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