I damaged a friends EAA Bipe so I ended up buying a kit. Damage mainly to lower wing so I copied parts and replaced his wing while doing a complete rebuild. The lower wing on the one I built has a lot more positive incidence than on the plans. I checked his and his lower wing had a lot of positive incidence on lower wing. He just has lower ailerons but I put both upper and lower on mine. It makes no sense to have a lot of incidence different than top wing especially on his. His lower wing will stall before upper with a loss of aileron control.

I was curious what other people have done with this.

BTW, I am putting a Stinger 20cc RE single cylinder 2 stroke on mine. I prefer the twin cylinders but the single is lighter.

BUSA usually does a good job of producing plans that you could scratch build from. That said, it would not be the first time that there were differences between the plans and the kit parts. According to the usual theory of such things you would lose aileron effectiveness while the top wing is still flying but in actual practice it might not make that much difference. I've also known people who swore that the lower wing needed more incidence and should stall first. It sounds like your buddie's plane was flying with the greater incidence on the lower wing before the crash. The bottom line would be how did it/does it fly? Was the damage due to a loss of aileron authority?

The damage was when I walked by and he said " fly this thing". I took off on runway when I should have done grass. It darted right then left off run way. Totally my fault.

You wouldn't be the first one.
What I was wondering is, did the plane fly okay prior to the damage or was your buddy asking you to fly it because it was giving him troubles?

Every bipe that I have built has had more incidence on the bottom wing then the top. Most have 4 ailerons but the last, an Aeromaster has ailerons on only the bottom wing. All have flown well. IMO having a situation where the bottom wing stalls but the top wing has not would be for a split second at most.

I know it flew but I couldn't tell you what the characteristics were. I have built 4 BSUSA Phaeton 90's. What is funny with the last one I built, the errors in the instruction manual were the same as they were in 1985.