Originally posted by SIK1
The whole wing doesn't stall at once, it is progresive. I just can't remember if it's from tip to root or root to tip. The buffet is the turbulant air moving over the wing, and turbulant air is bad for aerodynamics
The stall should start closer to the root and progress outward. Most planes (all?) are designed so that happens. My factual knowledge regarding this is sparse, but IIRC the stall generally starts about 1/3 of the way out on the wing from the root. I believe twin-engine prop planes have their engines mounted here at least partially due to this, in an effort to delay the onset of the stall. I could be wrong though- maybe someone else will supply more facts.
I'll throw a basic explanation out that can be corrected by those who know better...
I know that what you really want to avoid is a stall out at the wingtips. Those are usually a pretty violent stall without much warning. The type where one wing drops rapidly, rather than the nose of the plane gently dropping or buffeting.
Those that build R/C planes may recall on the simpler rib and spar constucted wings that "washout" would be added to the wing by warping the leading edge of the wingtips down a tad to create a lower AoA near the wingtip. This forces the stall to occur closer in to the wingroot. More modern R/C sheeted wings are designed so that as you build them washout is added without any real input from the builder. It's still there if you look closely though.
I have no idea whether WW2 planes had washout built in or not. I'd be shocked if modern private planes didn't have washout, but I really don't know.
Dropping flaps would also seem to have the same effect, but to a much larger degree. It makes the inner portion of the wing have a higher AoA than the tips, again making the tips less likely to stall first. This is good since often when flaps are down you are low and slow where a violent wing-dropping stall would be bad.
When you use aileron you increase the angle of attack at the wingtip for one wing, while lowering it for the other. The tip with the elevated AoA is the one you are trying to make go upward (left wing for a right roll). This actually makes that wingtip more prone to a stall, which would cause your left wing to drop while applying more right aileron, which is bad. You'd likely correct instinctively with full right aileron to counter, and that would be very bad.
At high enough airspeed this isn't as apparent as at low speed, especially near stall.
Before that stall occurs you do see signs of "adverse yaw effect" which is caused by the lowered aileron creating more drag than the raised aileron. This gives you a left yaw for an application of right aileron. The left aileron creating more drag will cause the left wing to slow down and drop, while the right wing speeds up and raises. If allowed to continue this will eventually result in the left wing stalling and initiate a spin.
Of course you should be countering this adverse yaw effect by applying right rudder with right aileron, and left rudder with left aileron (coordinated turn). This helps to keep the higher drag wing at a higher airspeed to avoid those bad consequences.
MtnMan
