I got to finally go flying Sun. I used a Hy-bred plane. See "Got my jones off" in the Glider and Sailplane forum. When I got the plane trimmed out I noticed that is was flying best with down elevator ( about 5 degrees of trim). I know this is not aerodynamically clean. Which way should I move the wings incidence and about how much? The elevator is 1 7/16" wide x 22" long.

If you needed down trim... you need to shim the TE of the wing up.

I use 1/32 inch increments mostly... the first shim I would use in your case would be 1/16, as I would expect it to need at least that much.

Many people use 1/16 as thier test incriments then do the 1/32 or even 1/64th to fine tune.

If you are shimming slowly... you have less chance of making thengs very bad very fast.

Thanks. As soon as I get out to the field again I'll give it a try. I'll make up some shims to take with.

Another thing to look at (if its adjustable)....

Sometimes you create less drag shimming the horiz stab than the wing. does the fuselage look lkie its flying straight with the airplane's flight path... or like the nose of the fuselage is up just a bit? If the fuselage looks like its level, then try to shim the tailplane if possible. (1/2 as much as the main wing... it has more effect because the chord is smaller... thus the same thickness makes a bigger angle change)

Just a little food for thouhgt...I had a similar problem with a sailplane and moving the CG forward corrected the problem...helped many issues.

Troll,
I worked hard to get the c/g to the point were I like it. The c/g is back quite a bit from the plans location, but the plane flies well and indicates lift nicely. With the c/g were it is the plane also has a good speed range and slows down well for landings. I hear what your saying about moving the c/g forward but in this case I'm going to adjust the wings incidence.

FHHuber,
Alsa the tail plane is fixed.