The effect of boundary-layer control by suction and several high-lift devices on the longitudinal aerodynamic characteristics of a 47.5 degree sweptback wing-fuselage combination Page: 2 of 45
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NACA RM No. LE18
NATIONAL AWIXSORY CcOMmTI FR AERONAUTICS
TEE EFFECT OF BODlARY-LAYER CONTROL BY SUCTION AND SEVERAL
RIGE-LIFT EVICES ON THE LONGITUDINAL AERODYNAMIC
CHARACTERISTICS OF A 47.50 SWEPTBACK
By Jerome Pasanmanick and Anthony J. Proterra
An investigation has been made in the Langley full-scale tunnel
of a 47 .50 sweptback wing-fuselage combination equippe ' r _boun -
layer control by suction. The wing section was NACA 641-All2 normal to
the quarter-chord line, the aspect ratio was 3.5, and the taper ratio
was 0.5. The wing configurations tested included the wing with various
combinations of extensible leading-edge and split flaps.
Increasing the Reynolds number from 2.1 X 106 to 7.1 X 106 an
2.1 )X 106 to 5.0 X 10o had no appreciable effect on the lift and drag
characteristics of the plain wing and the wing with semispan split
flaps, respectively. The increase in Reynolds number, however, caused
a destabilizing shift of the linear portion of the pitching-moment
curve and. progressively moved an unstable break in the curve near the
stall to higher lift coefficients.
Combinations of slots utilizing the O.20)-ercent-hord slot,
are the most effective for boundary-layer control as initial separation
occurred near the wing leading edge. Applying suction through the
0.70-chord slot was not effective in imprvngthe wing characteristics.
The maximum lift coefficient of the plain wing was 0.96, 1.07,
and 1.11 for suction flow coefficients of 0, 0.024, and 0.037, respectively
Boundary-layer control did not eliminate an Inlstable pitching-moment
break that occurred near maximum lift.
Semispan and full-span split-flap deflection resulted in maximum /
lift coefficients of 1.02"an 1.09, respectively. Applying a suction
flow coefficient of 0. 037 increased the corresonding-maximum lift
coefficients to i.14 and 1.23 . With and without boundary-layer control
the model was longitudinally unstable at the stall.
The application of boundary-layer suction with the 0.50-, 0.60-,
and 0 .71-semispan extensibe leading-edge flap configurations produced )
maximum liit cerr i ae ~rfi4TI-,1 , 1.7, a--I l.18, respectively. Without
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Pasamanick, Jerome & Proterra, Anthony J. The effect of boundary-layer control by suction and several high-lift devices on the longitudinal aerodynamic characteristics of a 47.5 degree sweptback wing-fuselage combination, report, November 4, 1948; (digital.library.unt.edu/ark:/67531/metadc57685/m1/2/: accessed November 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.