Originally Posted by
MEMpilot
Yeah its very improbable, mostly of interest in understanding aerodynamics for why a cessna-type door, when cracked slightly and pushed against the wind resistance, would cause an airplane to yaw in the opposite direction. I just can't make entire sense of it.
I think twin wasp pretty much has it. Say your looking at the top of the aircraft, and the rudder is deflected left. This causes a high pressure area on the left side of the vertical stab, in turn causing it to move right towards the (relatively) lower pressure. Since this pressure differential is located BEHIND the centroidal vertical axis, the entire aircraft yaws left.
The same effect happens with the doors, although the pressure differential will take place FORWARD of the centroidal vertical axis. Say again you open the left door, higher pressure left side wants to move right. But this force is now applied infront of the vertical axis, and the aircraft yaws right.