A transonic wind-tunnel investigation of the effects of nacelle shape and position on the aerodynamic characteristics of two 47 degree sweptback wing-body configurations Page: 3 of 89
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NACA EM L52GO2
interference drag. Further chordwise and vertical movement did not
result in any appreciable drag reductions but had a favorable effect
on the drag-break Mach number. At Mach numbers up to about 0.80, the
strut and strut-end junctures of the pylon-suspended nacelles appeared &
to be responsible for a large interference drag.
Moderate thickening of the wing root was accomplished without
penalty in minimum drag or maximum lift-drag ratio when the nacelles
were submerged in the wing root aft of the maximum-thickness station.
At high Mach numbers the wing-tip nacelles had the lowest incremental
drag coefficients and the highest maximum lift-drag ratio values of the
various nacelles investigated on the 6-percent-thick wing-body
configuration.
In general, the various nacelle configurations caused small
reductions in the drag-break Mach number and produced small increases
in the lift-curve-slope characteristics of the basic models. The pylon-
suspended and underslung nacelles produced destabilizing moments, whereas
the submerged and wing-tip nacelles caused stabilizing moments of the
basic models.
INTRODUCTION
The NACA has been conducting a broad program of research to
determine the aerodynamic characteristics at supersonic speeds
(refs. 1 to 3) and at transonic speeds (refs. 4 and 5) of wings varying
in thickness ratio and in sweep for use on a high-speed bomber. The
present paper presents the results at high-subsonic and transonic
speeds of a nacelle investigation conducted on two wing-body combinations
of this series. The wings both had 47o sweepback based on the 0.25-chord
line, aspect ratio 3.5, and taper ratio 0.2, but differed in root-section
configuration. Underslung, pylon-suspended, and wing-tip nacelles were
investigated in conjunction with one of these wings which had 6-percent-
thick sections throughout. Nacelles submerged in the wing root also
were studied on this wing and on the second wing which had a root section
that varied linearly in thickness ratio from 12 percent at the plane of
symmetry to 6 percent of the 40-percent-semispan station. The underslung
and pylon-suspended nacelles investigated on the 6-percent-thick wing
formed:L a consistent family in which forward movement of the nacelles
was accomplished by proportional downward movement so that the trailing
edge of the wing always cleared a 300-included-angle conical surface
extending aft from the nacelle exit.
The results reported herein consist of lift, drag, and pitching-
moment measurements for a Mach number range of 0.50 to approximately 1.12.aC
2
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Bielat, Ralph P. & Harrison, Daniel E. A transonic wind-tunnel investigation of the effects of nacelle shape and position on the aerodynamic characteristics of two 47 degree sweptback wing-body configurations, report, September 2, 1952; (https://digital.library.unt.edu/ark:/67531/metadc64693/m1/3/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.