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Old Sep 15, 2012, 02:58 PM
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Palmdale, CA
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There is one (1) force on a fixed plate in a moving airstream, or a moving plate in a fixed airstream.
We can resolve that force into the directions of interest. The resolution of the force up (or down) perpendicular to the direction of the airstream we call Lift.
The resolved force in the direction of the airstream we call Drag. With a good combination of air flowing over the plate and area of the plate, the object in question will move. Restrained, as in a wind tunnel, the forces on the supports for the model can be resolved into the desired directions.. Up(or down) is called Lift, and (restrained by the support) in the direction of the airflow we call Drag.
Flying machines can make Lift with motion forward into an air mass, using a propulsion system to "thrust" it forward. And by cleverly making the flying machine light and stiff, with lots of area that is also cleverly designed to permit the machine to rise off the ground with sufficient forward motion, provided by the propulsion system.
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