• Version
• 194 Downloads
• 4.46 MB File Size
• 1 File Count
• September 1, 2016 Create Date
• September 1, 2016 Last Updated

National Advisory Committee for Aeronautics, Report - Formulas for the Supersonic Loading, Lift, and Drag of Flat Swept Back Wings with Leading Edges Behind the Mach Lines

The method of superposition of linearised conical flows has
been applied to the calculation of the aerodynamic properties, in
supersonic flight, of thin fiat, swept-hack wings at an angle of
attack. The wings are assumed to hate rectilinear plan forms,
with tips parallel to the stream, and to taper in the conventional
sense. The investigation carers the moderately supersonic speed
range where the M'ach lines from the leading-edge apes lie ahead
of the wing. The trailing edge may lie ahead of or behind- the
lld'ach lines from its apex. The case in which the Mach cone
from one tip intersects the other tip is not treated:

Formulas are obtained for the load distribution,_the total lift,
and the drag due to lift. For the cases in which the trailing edge
is outside the ZL-[ach cone from its apex (supersonic trailing edge),
the formulas are complete. For the wing with both leading and
trailing edges behind their respectice Jfach lines, a degree of
approximation is necessary. It has beenjou‘nd possible to give
practical formulas which permit the total lift and drag to be
calculated to within 2 or 3 percent of the accurate linearized-
theory ralue. The local lift can be determined accurately ocer
most of the wing, but the trailing-edge—tip region is treated only
approximately.

Charts of some of the junctions derired are included to facili-
tate computing, and several examples are worlced out in outline.

It is customary, in supersonic wing theory, to describe
any straight segment of the boundary of a wing plan form as
supersonic or subsonic accordingly as the segment lies out.-
side or is contained within its foremost Mach cone; that is,
as the component of the flight velocity normal to the edge is
greater than or less than the speed of sound. These two
circumstances result in flmdamentally different types of flow
over the surface. It is apparent that the real reference is
not to a property of the wing plan form, but to a combination
of plan—form geometry and the velocity of the wing relative
to the speed of sound.