Hi Chaps
Very interested to read ShockWaves last post. If the sim (and prob therefore the aircraft) goes to 33 deg on a recovery and stops there, then it sure is thanks to the FBW rather than the aerodynamics. Aerodynamics could well make it recover but they would not stop at 33 deg.
As to the PA44 story, I think it is a very important lesson for aero eng studes. For the first two entries (and they were all entered the same way) I made sure that my last aileron input before releasing the controls was in to the turn and on the third my last input was out of the turn. Because of control circuit friction releasing the controls does not quite centre the ailerons. Thus the manoeuvres were not the result of just the spiral stability.
My bottom lines for these studes re spiral stability (since we seem well into the subject here) were
One. If you ask pilots whether the aircraft they fly are spirally stable they usually will look blank (which I cite as evidence that spiral stability is not a very important characteristic for pilots compared to many other handling related issues)
Two. If you ask pilots to check with a test on their next flight (put into turn, release and observe) they may well come up with the wrong answer
Three. If you are an FTE and need the answer from your pilot you must give him some sort of indicator that will enable him to check the ailerons are neutral for the test.
As to Keith’s point about ShockWaves second question how about:
In non FBW aircraft spiral stability works because the aerodynamic design of the aircraft is arranged so that (in a controls free turn) any disturbance that results in an increase in bank angle also results in a small sideslip angle being generated which slightly increases the angle of attack of the lower wing (and also reduces the angle of attack of the upper wing) thanks to something called the dihedral effect.
End of broadcast.
Good here init
Regards