Aesquire
Well-Known Member
N
In the teeter totter /see saw pitch stability Analogy, the Center of Gravity is in front of the Center of lift, ( on most "normal" airplanes w/out unstable fly by computer ) pulling the nose down. The tail pushes down ( or canard up ) to counter balance the offset. The pivot in that calculation is at the Center of Lift.
The important thing is that the pull of gravity doesn't ( noticeably ) change, while the tail force varies with airspeed.
One approach to making a "stall resistant" aircraft is to limit tail size so it can't hold the nose up at speeds and ( the related but not fixed ) angles of attack high enough to stall. ( in level flight ) This works, but has consequences. It makes for a lousy bush plane, since you can't slow down all the way to stall in unaccelerated flight. ( but can in a dynamic maneuver like a zoom climb ) Don't know any contemporary designs in production that use that "trick", but it was used in some 1920-30s "Safety Plane" competition designs.
Thank you. To clarify, the Center of gravity indeed is where the plane rotates around in flight.To add to Aesquire's post: the wings center of lift isn't the pivot point. The aircraft's center of gravity is the pivot point. But, other than that, his premise is quite correct.
In the teeter totter /see saw pitch stability Analogy, the Center of Gravity is in front of the Center of lift, ( on most "normal" airplanes w/out unstable fly by computer ) pulling the nose down. The tail pushes down ( or canard up ) to counter balance the offset. The pivot in that calculation is at the Center of Lift.
The important thing is that the pull of gravity doesn't ( noticeably ) change, while the tail force varies with airspeed.
One approach to making a "stall resistant" aircraft is to limit tail size so it can't hold the nose up at speeds and ( the related but not fixed ) angles of attack high enough to stall. ( in level flight ) This works, but has consequences. It makes for a lousy bush plane, since you can't slow down all the way to stall in unaccelerated flight. ( but can in a dynamic maneuver like a zoom climb ) Don't know any contemporary designs in production that use that "trick", but it was used in some 1920-30s "Safety Plane" competition designs.