Originally Posted by SilentPilot
If (like I assume they do) tailplanes create negative lift to balance the aircraft then why do aircraft designers not place them in such a way that as soon as a wing is set to stall the stab goes into the wing shadow, causing it to lose effectiveness and unstall the wing?
Basically, you use the CG to pull the nose back down and un-stall the wing. so as the wing stalls it produces less lift, meaning the force of gravity acting on the CG ahead of the Center of Lift will cause the nose to lower and then in turn the angle of attack of the wing to lower, which lets the wing start flying again.
The reason for doing this and not as you described is you'd never want to cause the loss of flow over the control surfaces. If for some reason the CG was incorrect (aft) and the elevator was blanked by the wing there would be no way to bring the nose down, thus the plane would fall, in a stall, all the way to the ground.
(the above is a very
simplified synopsis of the topic)