Computer program computes zero lift wave drag of an entire aircraft including any combination of the wing, body, pods, fins, and carnard. The program computes the external volume of the wing and the axial area distribution of the wing equivalent body

Craidon, C. B.

Harris, R. V., Jr.

English

NASA Technical Reports Server

December 1967	 Brief 67-10530 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Program Computes Zero Lift Wave Drag of Entire Aircraft 
The problem: 
To develop a program to compute zero lift wave 
drag of an entire aircraft including any combination 
of the following components: wing, body, pods, fins, 
and canard. Two optimal aims of the program are to 
compute the external volume of the wing and to com-
pute the axial area distribution of the wing equivalent 
body. 
The solution: 
Since the rule was formulated, and verified experi-
mentally, that the transonic wave drag of an aircraft 
is essentially the same as the wave drag of an equiva-
lent body of revolution having the same cross-
sectional area distribution as the aircraft, attempts 
have been made to estimate aircraft wave drag by 
examining the equivalent-body area distribution. 
It has been found that reasonably good wave-drag 
estimates can be made near Mach I if slender-body 
theory is applied to the aircraft area distribution. 
This procedure can be extended to higher speeds with 
good results by using the supersonic area rule to de-
termine the equivalent-body area distributions. 
How it's done: 
A major problem in adapting this procedure to 
machine computation is that of describing a rather 
complex aircraft to the computer in sufficient detail. 
The location of all the aircraft components are re-
ferred to an X-Y-Z axis system with the origin at 
the nose of the fuselage. The variation in fuselage 
radius along the axis between stations is assumed to 
be linear. Pods are similarly described. The wing is 
described as a sequence of streamwise airfoils dis-
tributed along the span. The contour of the wing is 
assumed to be linear between successive ordinates. 
The horizontal and vertical tails are described in a 
manner similar to that of the wing.
Once the aircraft description has been stored in 
the memory unit of the computer, the equivalent-
body area distributions are determined by solving for 
the normal projection of the areas intercepted by a 
family of cutting planes tangent to the Mach cone. 
In addition to the aircraft wave drag, the program 
lists the wave drag of the aircraft equivalent bodies 
at each Mach number as well as selected equivalent-
body area distributions. This additional information 
is particularly useful in tailoring a configuration for 
minimum wave drag because, in order for a config-
uration to be optimized at some supersonic speed, it 
is necessary to examine the series of equivalent bodies 
corresponding to the particular Mach number. It 
should also be noted that the area distributions re-
quired in the computation of sonic-boom overpres-
sures are provided. 
Notes: 
I. The program is written in Fortran IV for use on 
the IBM 7094 computer. 
2. Inquiries concerning this program may be di-
rected to:
COSMIC 
Computer Center 
University of Georgia 
Athens, Georgia 30601 
Reference: B67-10530 
Patent status: 
No patent action is contemplated by NASA. 
Source: Charlotte B. Craidon 
and R. V. Harris, Jr. 
Langley Research Center 
(LA R- 10079) 
Category 06 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000529 2020-03-11T21:00:31+00:00Z


Program computes zero lift wave drag of entire aircraft

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server