|
Bicycle Bob-
On aircraft the center of pressure is generated on the wing. Cg is actually forward of Cp normally. The tail actually raises the nose constantly. Yes, this causes more drag, but otherwise the aircraft would be unstable in pitch(The Wright 1903 Flyer was not designed this way, and was consequently nearly impossible to fly. In the next few designs the Wrights figured this out.) This is why pilots usually calculate CG before every flight, because a too far aft CG could make the plane uncontrollable. Also, a technique to increase range on airplane is to load as close to the aft CG limit as possible to reduce the horizontal tails load, and thus the trim drag it produces. The original question was about a vertical fin, however, which along with the rudder acts in yaw to keep the plane pointed toward the relative wind and not slipping. It seems like adding one to a car would cause problems just for this reason. You don't really want a car that always wants to point itself into the relative wind.
|