Chris, Im new to posting, although ive been lurking for a while. I'm an aeronautical engineer, have my own interest in flight. Olecopter's (mid mounted prop systems). The simple questions are always the most difficult, how does the Arduino cope with translations through 90 degrees? is the frame of reference used a quarternion based or an euler frame of reference? If you have a look at my page the machine translates through the vertical take off axis, to a horizontal flight mode. I could only find 1 autopliot which used quarternions and did not incur a fudge through 89.5 degrees and 90.5 degrees which most do.
Hope you can help me as the alternative is 1) human controlled vtol, 2) angled take off to not incur an infinity at 90 degrees.
Regards Eddie Strickland