ORIGINAL: flycatch
This is my second biplane. The first being the GP Stearman and it had no trim problems like the BH Pitts. The instruction manual for the Pitts provided no information on incidence angles nor did the manual supplied by GP. I assumed the engineers did their home work for the modeler. We all no what assumptions can and do make and ass out of you and me. The only modification I made to the Pitts was moved the CG back torward the TE of the top wing. I did this because their location would make the plane extremely nose heavy. I'll guess I'll live with this problem because there is no way you can reconfigure the mounting of the top wing assembly.
After re-reading all this....again....
Great Planes "normally" does a solid job engineering with themajor airframe build, construction and flight characteristics, but BH does not...period, so check everything. Besides, nose heavy is fine, the CG could be off the LE of the bottom wing and it wouldve flown fine. Now move it aft just a bit TOO far.....again no bueno. FWIW the top wing CAN be re-configured completley if you so choose. Its actually very simple depending on what kind of top wing incidence you are wanting to use youll only need to shim/adjust the wing a minor amount. To correct my top wing, I simply re-drilled the top wings fwd mount hole a bit deeper into the wing tab. This allowed the LE of top wing to drop, hence loosing some of the positive wing incidence I had. I went from +3.8* incidence to roughly +1.8* incidencemoving the hole less than 1/4".....
Get creative and simply take your time.....make it want you want....