Originally posted by BMatthews
Ollie, I'm not so sure I'm with you on this one. Full size airliners use basic barn door types to good effect for minor corrections with the ailerons only coming into play for the more meaningful requirements.
But I do agree that some experimentation is in order to determine the size and placement on the wing. I'm thinking that there is a reason why the roll control spoilers on the airliners I've flown on and the MU2 are placed far to the rear on the airfoil.
BM, not entirely correct on spoilers. Spoilers are an integral part of the flight control system on real aircraft. They are propotionally mixed in with aileron inputs, which allows much less flight control input. Spoilers used in roll control are mixed with aileron input and only deploy on the down-going wing, and will always start deploying from the most inboard position, gradually increasing displacement outwards. This is why airliners use multiple spoilers. In speedbrake use, they are deployed symmetrically in varying degrees. As ground spoilers, they are used after touchdown to spoil lift and increase braking effectiveness. You will almost always find the spoilers located directly in front of the flaps on a real aircraft. This adds stability on rollout, as lift is being dumped from the very areas of the wing where it is being created by the flaps.
A couple things to remember if using spoilers.
Use VERY LITTLE deflection!
Do not use spoilers and flaps at the same time, they will negate the purpose of having flaps deployed and greatly increase drag.