RE: Rutan Voyager 90 degree roll
I'd guess that is a right-side-up only airplane and that it's mission profile was designed to avoid any extreme manoevering. It was designed for very long range flights, and if you set it up on the proper course at the beginning of the flight, then it should need nothing more than very mild course corrections enroute. If you have to bank 90 degrees, then you were heading the wrong way, and wasting fuel (and range)..