GP Ultimate wing incidence
#2
noahb: I have had 2 of these planes and they fly great. I set both up with the lower wing 0 incidence to the horz stab and .5 deg neg on the top wing. the cg is critical on these planes. set it as per plans. hope this helps.
#3
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Joined: Nov 2002
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From: Framingham,
MA
I have my GP Ultimate almost ready to cover. I'm currently working on the wing incidence adjustments. Browsing old posts, there are many ideas on how to adjust the wing incidence on a biplane. From what I gathered, a positive incidence on the top wing should give the plane a better stall (tip forward), but many people recomment a slightly negative incidence on the top wing instead. What is the theory behind the negative incidence on the top wing ?
From the GP plans, the recommended incidence is 0-0-0. Reading old posts on this matter, some peoples experience says that this would result in some pretty bad flight characteristics. But then on the other hand, from what I hear this GP Ultimate should fly pretty well. So I'm having a hard time collecting information on this matter in a consitent manner and I'm inclined to go with the recommended 0-0-0 angles for my model. But this is also the time to make these kinds oj adjustments... So, has anyone tried different wing incidence setting on their Ultimate ? What were the results ? Which one worked best ? The wings are staggered about 2" on this model, corresponding to about 25" of the root chord.
Also, I don't really have a feel for tolerances here. My bottom wing is currently -0.5 degrees. Is this worth adjusting to bring it back to 0 degrees ?
Thanks
Daniel
From the GP plans, the recommended incidence is 0-0-0. Reading old posts on this matter, some peoples experience says that this would result in some pretty bad flight characteristics. But then on the other hand, from what I hear this GP Ultimate should fly pretty well. So I'm having a hard time collecting information on this matter in a consitent manner and I'm inclined to go with the recommended 0-0-0 angles for my model. But this is also the time to make these kinds oj adjustments... So, has anyone tried different wing incidence setting on their Ultimate ? What were the results ? Which one worked best ? The wings are staggered about 2" on this model, corresponding to about 25" of the root chord.
Also, I don't really have a feel for tolerances here. My bottom wing is currently -0.5 degrees. Is this worth adjusting to bring it back to 0 degrees ?
Thanks
Daniel
#4
My experience with the ultimate is that even with a .46 FX on front (not the biggest engine), it seems to do nothing but climb with 0-0-0. I need to dial in alot of down elevator for it to fly straight, (Once having done that the airplane still flys great!) when i get some time i want to adjust the incidence to negative on the top wing. To change the incidence of a biplane is quite simple for the top wing atleast, just place washers in between the bolts and the wing. Hope this helps.
Adam
Adam





