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National Advisory Committee for Aeronautics, Research Memorandum - Supersonic Tunnel Tests of Two Supersonic Airplane Model Configurations

Supersonic Wind Tunnel tests of two models of similar supersonic airplane
configurations were made at Mach numbers of 1.55, 1.90, and 2.32 to
determine values of the drag, lift, pitching moment, yawing moment, and
side force. The two models had bodies, wings, and horizontal tails of
similar geometry, the horizontal lifting surfaces having taper ratios
of 2, aspect ratios of about h, and leadingredge sweepback angles of
about R30. The principal difference between the models was the vertical
wing location relative to the body axis and horizontal tail -one model
had a high wing and one model had a low wing. The test results indicated
no difference in the lift characteristics of the-two models and small
differences in the drag characteristics. The most significant results
shown by the tests were the variation with Mach number of the differences
between pitchingsmoment values for the two models, indicating the proba—
bility of differences in the rates of change of downwash angle with angle
of attack for the two horizontalatail locations relative to the wing.

The increased attention to supersonic aircraft and missile design
over the past few years has greatly accelerated the need for basic super-
sonic aerodynamic information.

Theoretical work has increasingly provided methods for
calculating the basic aerodynamic characteristics of components
such as bodies and a variety of wing plan forms; however, very little
experimental data is available to check the theory or to predict the
effect on lifting surfaces of a disturbed stream such as that produced
by a supersonic airplane fuselage or by another lifting surface. Theo—
retical methods at present appear very awkward for calculating the charac—
teristics of complete supersonic airplane configurations; thus, tests are,
at the present time, the only adequate means for studying such cases. m
Because of the general interest in the information it might provide,
tests of two supersonic airplane model configurations were made in the
Langley 9-inch supersonic tunnel.

The configurations tested do not represent designs approximating
optimums from present—day considerations, since their basic lines were
conceived in the early part of 1916. The models represent two versions
of a supersonic research airplane which was intended to be carried to
high altitude by a "mother" ship, released, and accelerafid to supersonic
speeds by rocket meters of moderate duration. The two models had similar
bodies and 11-30 sweptback wings and tail surfaces, the wings having sharp—
edged circular-arc sections. The primary difference in the two models
was the vertical location of the wing.