When we apply rudder (say left rudder) to a plane with dihedral, what happens?
(You can try this out if you don’t believe it: take a piece of paper and fold it slightly, like dihedral; then look at it end on, but slightly off-center, i.e. from the point of view of the approaching airflow. You will see that you can see more of the underside of one half than you can of the other.) And what does an increased angle of attack do? It increases the Cl and the lift generated by that half! So we now have the right wing generating more lift and the left less; the result is a roll to the left. With polyhedral we get the same effect, only to a larger extent. The Stall: If you try to fly slower and slower by pulling back on the stick (i.e. applying up-elevator) you will reach a point where the plane “falls out of the sky” or the stall. What happens is that an airfoil will only “work” up to a certain angle of attack. When that angle is exceeded, the airflow above the airfoil breaks up and the result is an increase in drag and a drastic decrease in lift, so that the wings can n
