Maybe some of you guys can help with some U-KEY( the Joe Just design) trimming problems. In reality, the guys solved the slightly O.B. wing high problem with a trim tab after first checking and adding some tip wt. That brought the O.B. WING INTO TRIM. The wing was checked carefully for any twist/warps/incidents and was dead-on and stab was straight, etc. The one thing we did notice was the lead-outs at the tip were not at the same height as the bell crank lead-outs-they were lower at the tip over (3/8").
We had another homemade stunter w/ exposed bellcrank similar to the U-KEY installation except the tip lead-outs were over 3/4 " below the bellcrank height. The O.B.wing flew very high level upright flight and very low level inverted flight. Tip wt. not the problem again. We did not put a tab on the O.B. WING.
We were wondering if the problem could be corrected by raising the lead-out guide to the same height as the bellcrank, if this is really causing the problem. I have looked at other U-kEYS ON THE Web and the leadouts look to be even w/the bellcrank. The wing on this plane is foam and it is straight and true. Both airplanes had aluminum landing gear ( 2 wheels). My question is does the lead-out exiting well below the centerline of the B.C. on an external bellcrank that is above the C.O.GR on top of the airfoil cause this problem, if you have a wing that is true in all regards and no misalignment problems, or is it some other problem such as the wt. of the landing gear below the the C.O.G. IN COMBINATION W/ THE TOP MOUNTED B.C?
We did not have the time or parts on hand at the field to resolve the problem at the field yesterday.
I have looked throughout this forum to see if others had similar problems with their U-KEYS or similar designs and have found no one mentioning these problems.
Thanks,
Doug