As planned I went ahead and test flew the UB this weekend. Had 5 incredible flights. I flew all flights with the drop tanks attached. I reckon thats the reason I needed about 1/8 inch up trim for straight and level flight. With take off flaps, the elevator is flat, and with full flaps and 5/16 crow, I needed 1/8 inch down trim. Obviously I have set up conditions to handle all this. Now the plane flies very well under all 3 conditions. I started with a 4 min timer and by the 5th flight put it up to 5 mins. I am sure it will handle 6 mins of fast flying with the small tanks. No more than 6 though. Will the elevator trim change without the tanks? Does it fly faster without the tanks? I dont like to see that UP trim How much aft can the CG go from here?
thanks guys for all the advice. Its a fantastic airplane.