Wing or elevator incidence problem?
 

I am having an incidence problem with my new 35% edge I think. This is a plane that I did not do the initial part of the construction on. I admit that this stuff is new to me. The plane requires 3/8" up elevator trim to fly straight. I'm not sure if it is the wing or elevator. Here are a few other facts: (1) In the landing pattern and inverted flight (no forward stick required) the plane seems to fly fine CG-wise; (2) The horiozntal stab is off square with the wing some (A good builder friend of mine says he can help me fix the stab); (3) On the first takeoff role, the plane nosed over when it approached flying speed (tail off ground). I saved it, but she definitely noosed over a good bit. Once airborne it required the 3/8" up trim for level flight. It seems to fly ok, with the required trim, at least at my skill level. Things not like they should be just bug me though.

I am thinking that the problem must be the elevator because I set the wing incidence using the manufacturers recommendation. the original owner built the elevator. thanks, Steve

RE: Wing or elevator incidence problem?
 

It sounds as if your horizontal stab has negative incidence relative to that of the wing. If the stab is glued in, this can be quite a job to fix, requiring cutting the stab loose and resetting the incidence. Correct stab incidence is very important, since you can't trim out an incidence error, except by the use of elevator trim tabs, something I am using increasingly on my own models. Otherwise, I avoid glueing in the stab, attaching it with bolts so that it can be shimmed a bit to correct those almost unavoidable small incidence errors. I have also warped the stab to get its average, effective incidence correct, which can only be determined by careful flight testing, but this can also be very tedious work.

RE: Wing or elevator incidence problem?
 

You may have to much downthrust in the engine, have you checked that?

RE: Wing or elevator incidence problem?
 

Normaly the horz. stabilizer is fixed to the fuselage and the wing incedence is adjusted to it. Yes excessive downthrust could cause this problem.

RE: Wing or elevator incidence problem?
 

The plane has removable horizontal stab (bolts), so it is easily adjustable. the easily adjust also, but since I set it I'm sure its correct. I should have checked the stab at the same time I did the wings, but can't think of everything. But I'm pretty sure its the stab. But now that I know how to check this stuff I am positive its the stab.

RE: Wing or elevator incidence problem?
 

Normaly,when you check the incidence of a wing you check it with the stab. Every thing on the plane is usually aligned from the stab, including downthrust, What did you adjust the wing incidence too?

RE: Wing or elevator incidence problem?
 

Probably you should prop the fuselage up on a level table to be what you would expect to be 'a flying condition', see if the front tip of the wing (front most part of the leading edge) and back of the trailing edge of the wing are 'pretty close' (within reason), check to see if the stab is horizontal and see if the prop is close to 90 degrees to the table. You might have an error in each of these areas so that each contributes to poor handling.

If the plane glides in for a landing with no problems (with the engine at idle or completely OFF and just a little up elevator) but with power it acts very odd then the engine thrust line probably needs adjusted.

Maybe you can update this thread when you have some observations and let us know what you finally changed.