My ol' Cessna 150 had a mechanical stall warning system. It was a plastic party horn with the noise making reed reversed so that it would make noise when you sucked on it. It was attached to the stall port with a tube so when the angle of attack reached a certian point the horn would sound. I used to take it up and do what I called wheep stalls. You'd slow the plane as you increased A of A until the horn just began to wheep, then I'd pull and release the control yoke to make the horn go wheep wheep wheep. Ah to be that young and stupid again. I guess my point is(other than stroll down memory lane) that the stall port is near the wing root and while the root was approaching stall, washout allowed for good control at the ailerons.