About 3 year ago I built this airplane using the R/C M plan called cloud 9er as a guide. It weighs 8.5 lbs. with a 71" span power is a Super Tigre 75. I estemate the top leval flight speed at 80mph and slow flight speed at under 20mph. It has split flaps that create a lot of drage. I operate the split flaps with the gear channel. Then it has flaperons controled with the flap and aleron channels mixed. The wing has a semisemetrical airfoil that is built flat then the tips turn to flat bottom with a hole lot of washout. I built thr fin and rudder larger than the plans show. It will do most aerobatic manuvers but it is unstable during inverted flight it is a real chalinge to fly an inverted figure 8 but it can be done. to see it go to http://greenbush.org/~mike.fisher/dad/yellowbird.html I realy enjoy flying it I think it could be saled up.