Originally posted by Diablo
Say Doug:
Could you explain why negative wing incidence will make a model pull to the belly in the downlines? Others claim positive incidence will make a model pull to the belly in the DLs. The explanation I read is that the + incidence requires some down elevator trim in the horizontal lines with the power on. When the plane flies the downlines with the power off, the down elevator trim makes the plan pull to the belly. What am I missing here?
Sure thing..
What's important to look at is the relation between the wing and stab.. Using hypothetical values.. let's say the Wing is at +2, and the stab is at 0. From a trim standpoint.. this is sort of an up elevator trimmed incidence because the stab is -2 relative to the wing..
Now if you remove 1 degree in the wing, moving it to +1, with the stab still at 0, you have effectively reduced the trimmed downforce (up elevator) generated by the stab as the stab now is -1 relative to the wing.
Proper trimming is a total balancing act.. Without a doubt.. the most important process in trimming is to do one thing at a time, and re-fly. Otherwise.. it's very hard to determine what change had a given effect.
-Doug Cronkhite
-Team JR