ORIGINAL: turnnburn
I have no down thrust on my Elan and it flies just fine. In fact if anything I have noticed at the bottom of high speed power on dives it feels almost like it wants to tuck a little bit and I seem to need an unusually high about of up elevator to make the pullout. having said that I initially flew it with a Wren Supersport (17lbs thrust engine) and never noticed this tendancy but I know have the equivilant of a P 120 sized ( 28-30 lbs) and it has only been with this engine on there that I have noticed this.
I recently shimmed my horizontal stab up about 1/8'' so the airplane no longer needs a bunch of up elev trim to fly level and I havnt noticed it tucking anymore, but I havnt really done much in the way of high power high speed dives and pullouts since shimming it.
Good you brought that up, on the Elan thread its been named the "Wooly elevator syndrome" lots of disscusion on why it happens, but no real conclusions, I suspect too much Expo and or C of G can possibly be the culprit in some circumstances.
Mike