aerodynamic center


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aerodynamic center

[‚e·ro·dī′nam·ik ′sent·ər]
(aerospace engineering)
A point on a cross section of a wing or rotor blade through which the forces of drag and lift are acting and about which the pitching moment coefficient is practically constant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

aerodynamic center (AC)

aerodynamic center (AC)click for a larger image
Moment about the aerodynamic center is constant with angle of attack. Aerodynamic center does not move with angle of attack.
The aerodynamic center is a point on the wing chord that results in a constant moment when the wing angle of attack is changed. An AC lies approximately at the quarter-chord position at subsonic speeds and at approximately the half-chord position at supersonic speeds.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Here, CL' is the lift coefficient defined in the cell coordinate system; q is the dynamic pressure; S is the reference area of the cell; [[alpha].sub.zl] is the zero lift angle of attack; and f is the distance between the aerodynamic center and point B.
They suggested that for acceptable stability of a WIG craft, the centre of gravity should be close to the height of aerodynamic center ([X.sub.h]), and it should be between the height of aerodynamic center and pitch aerodynamic center ([X.sub.[alpha]]).
There e or a is dimensionless distance from the aerodynamic center to the pivot.