area rule

area rule

[′er·ē·ə ‚rül]

(aerospace engineering)

A prescribed method of design for obtaining minimum zero-lift drag for a given aerodynamic configuration, such as a wing-body configuration, at a given speed.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

area rule

A prescribed method of design for obtaining minimum zero-lift drag for a given aerodynamic configuration, such as a wing-body configuration, at a given speed. For a transonic body, the area rule is applied by subtracting from, or adding to, its cross-sectional area distribution normal to the airstream at various stations so as to make its cross-sectional area distribution approach that of an ideal body of minimum drag. For a supersonic body, the sectional areas are frontal projections of areas intercepted by planes inclined at the Mach angle. In an aircraft, the cross-sectional area along the length of an aircraft should be kept as uniform as possible and with no abrupt changes. The cross section of the fuselage is reduced in the neighborhood of the wing root junction to compensate for the cross-sectional area of wings, with the consequent reduction of wave drag.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved