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National Advisory Committee for Aeronautics, Report - Lift and Center of Pressure of Wing Body Combinations at Subsonic, Transonic, and Supersonic Speeds

A method is presented for calculating the lift and center-of-
pressure characteristics of circular-cylindrical bodies in com—
bination with triangular, rectangular, or trapezoidal wings or
tails through the subsonic, transonic, and supersonic speed
ranges. The method is restricted to wings which are unbanlced
and do not have sweptbaclc trailing edges or sweptfomoard leading
edges. The method is further restricted to small angles of at—
tack and small angles of wing and tail incidence. To obtain
the wing—body interference, certain factors are defined that are
the ratios of the lifi on the components in combination to the lift
on the wing alone.

These ratios are obtained primarily by slender-body
theory. The wing-tail interference is treated by assum-
ing one completely rolled-up cortex per wing panel and evaluating
the tail load by strip theory. A numerical example is included to
show that the computing form and design charts presented
reduce the calculations to routine operations. Comparison is
made between the estimated and experimental characteristics
for a large number of wing-body and wing-body—tail combind
tions. Generally speaking, the lifts were estimated to within
:I;IO percent and the centers of pressure were estimated to
within $0.02 of the body length.

The problems of the interference among the components
of airplanes or missiles have received much attention be-
cause of their great importance in high-speed aircraft
design. This importance is due to the interest in designs
employing large fuselage radii and tail spans relative to the
wing span. One of the notable methods for determining
wing-body interference at subsonic speeds is that of Len—
nertz, reference 1; data supporting the work of Lennertz
are presented in reference 2. Laborious methods are avail—
able (refs. 3, 4, and 5) for computing the interference load
distributions of wing-body (or tail-body) combinations at
supersonic speeds. A simple method is presented in refer—
ence 6 for estimating the effects of wing-body interference
on lift and pitching moment when the wing is triangular.
One of the notable methods for calculating wing-tail inter-
ference in subsonic aircraft design is that of Silverstein and
Katzoff in references 7 and 8. For supersonic speeds,
Morikawa (ref. 9) has examined the four limiting cases of
zero and infinite aspect ratio for wing and tail and has
found that the loss of lift due to interference can be as large
as the lift of the wing itself for equal wing and tail spans.