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It will be seen from the above that the lift coefficient Ky increases with the aspect ratio, and that it generally declines after an angle of 30 degrees. The center of pressure moves steadily back with an increase in angle.

Example for Lifts

Solution

Under the same conditions, but with an aspect ratio of 3, the lift will become: L = KyAV² = 0.0014 x 200 x(50 x 50) = 700 pounds. In this case the lift drag ratio is 5.1, so that the drag will be 137.8 pounds. Even with the same area, the aspect ratio makes a difference of 865–700 = 165 pounds. If we were compelled to carry the original 865 pounds with aspect 3 wing, we would also be compelled to increase the area, angle, or speed. If the speed were to be kept constant, we would be limited to a change in area or angle. In the latter case it would be preferable to increase the area, since a sufficient increase in the angle would greatly increase the drag. It will be noted that the lift-drag ratio decreases rapidly with an increase in the angle.