I think you would find that a glider flying though air would stop moving
pretty quickly if you could turn off gravity! There would still be lift
and drag until it stopped, but nothing to drive it forward.

Derek Copeland


At 12:00 19 March 2009, Bob Cook wrote:

Gravity acts downward and no other direction.


Lift plus grivity act together and form a resultant force parallel to
the
direction of flight. Drag acts in the opposite direction at equal
magnitude.

Gravity (alone) is not the force that provides forward motion to a
glider.

A simple three vector diagram will show this.


Cook