With the nice (he says with tongue in cheek) square nose you have a great drag producer. A little yaw and you get much more drag than a nicely streamlined nose would produce and you slow down. Stick the square nose in the airflow and the dynamic pressure aft of it drops. Lower dynamic pressure from any of the causes means that at the tail the initial high speed trim is no longer working.

You end up with the airplane slowing down and pitching nose down. Make a nice streamlined nose and try the maneuver. It might make the rudder more effective.

------------------- I ask that because it's possible that you have some incidence that is being canceled out by the angle of the horizontal stabilizer, and that, in turn, is creating so much turbulence around the rudder that it's making it ineffective.

It's amazing how much the effectiveness of the tail can be affected by the wing. - Hence the fact that full size airliners have the stabilizer positioned as far out of the stream created by the wing as possible. ---------------

David, wrong concept. If you ignore the boxy front end (a really bad one I might add) and the bump of the headrest the lines are those of any classic pattern design as far as incidence goes. If I were making an airliner or competition glider I would get the tail high, it is a drag thing they are trying to minimize. The effectiveness of the tail to determine pitch is not really a position thing. Keep the speed up and it will work fine regardless of where it is.

As I have mentioned in other discussions I would offer in evidence the years of competition pattern airplanes most of which have the horizontal tail within inches of the wing horizontal line and all of which have great stabilizer/elevator effectiveness.