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• December 9, 2016 Create Date
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National Advisory Committee for Aeronautics, Technical Notes - Wind Tunnel Investigation at Low Speed of an Unswept Untapered Semispan Wing of Aspect Ratio 3.13 Equipped with Various 25% Chord Plain Flaps

Force and moment data were obtained at low speeds to determine the
aerodynamic characteristics of an unswept untapered semispan wing of
NACA 6hAOlO section and aspect ratio 3.13 equipped with 25-percent-chord
unsealed plain flaps having various spans and spanwise locations. Lift,
drag, pitching-moment, and flap hinge-moment data were obtained for the
wing with the various flaps deflected up to 60°.

In general, changes in angle of attack, flap deflection, or flap
span and spanwise location produced trends in lift, drag, pitching
moment, and flap hinge moment that were similar to but of different mag-
nitudes from those for unswept wings of higher aspect ratio. The incre-
ment of lift coefficient due to 300 of flap deflection was relativexy
unaffected by the spanwise location of the flaps and increased nearly
linearly with flap span. Because of the increase in the drag coeffi-
cients and the associated decrease in the values of the lift—drag ratio
with increasing'flap deflection, an advantage may be gained by limiting
the flap deflection to moderate angles (about 300), even though the lift
coefficients increase with further increases in flap deflection.

The National Advisory Committee for Aeronautics is conducting an
extensive investigation of the lift and control effectiveness of
various flaps and control surfaces on wings having plan forms suitable
for transonic and supersonic airplanes. The ultimate objective is to
obtain flap.and aileron design criterions similar to those available
for wings of conventional low—speed plan forms (references 1 to 6).

As part of this broad study, the lift and lateral control character—
istics of an untapered low—aspect-ratio semispan wing having various
amounts of sweep and equipped with 25-percent-chord unsealed plain
flaps or ailerons having various spans and spanwise locations are being
investigated in the Langley 300 MPH 7- by 10-foot tunnel.