What to do? -- The Plane SIG LT-25 -- Engine choices?

TT GP .28 glow -10.4oz- MAS 10x5@ 10,200RPM

OS FX .25 diesel – 10.7oz- MAS 11x5@ 10,200RPM

OS FP .40 diesel – 10.5oz MAS 11x7 or 12x5 @10,200PRM

The TT .28 glow will have enough power for this 4.5lb airplane

The FX .25 diesel will have plenty of power

Will the FP .40 diesel beat up the all balsa fuselage?

If I had those to choose from my choice would be one of the OS .25s. I have an LT 25 a great deal using a Saito .30 with a 10.5x5 Graupner, its a perfect combination. The .25s would be perfect also.

But will the .40 beat up the airframe?

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Francis a 40 diesel turns the prop of a 60 glow ,stick with the 25 OS diesel it approchs a 40 glow you just do not need that much power in that plane martin

francis,

i built this plane from the kit, and it flies great! at first i had an old OS 25 FP on it, and it flew beautifully. 9x6 prop, and it was great. 9x4 even better for landings. i recently put a 32 sx ringed on it, and boy what a difference. i can almost hover it. so i suggest going with a small engine. like a .15 diesel even. this airframe has so much lift. then move up to a larger one for fun.

tom

Got a couple of flights this morning and it flys great. I ended up using a OS FX .25 with Davis Diesel head. Pleanty of power on the 11x5 @ 10K RPM and a sub 3K RPM idle lets the plane sit still on pavement at idle.


Francis

How would a PAW .15 work on this plane? I have the engine sitting around and my son is almost old enough for a trainer this year.

I do not think a PAW .15 will be quite enough. It would be tough to ballance as a PWA .15 weighs 7.3 oz and the OS FX.25 weighs 10.4 oz..



Francis

Good point. Maybe something like the old Goldberg Eaglet would be better. I built one of those about 22 years ago, was a very fun/simple build.

hey i just picked up an eaglet that's half built. a PAW wouldn't be a bad idea. i'll have to keep a lookout for PAW .15! i like the look that plane.