Effects of sweep on the damping-in-roll characteristics of three sweptback wings having an aspect ratio of 4 at transonic speeds Page: 2 of 24
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UNCLASSFI ED
NACA RM L50J19
NATIONAL ADVISORY COMMITrlE FIR AER~IAUTICS
RESEARCH MEMORANDUM
EFFECTS OF SWEEP ON TEE DAMPING-IN-ROLL CHARACTERISTICS
OF THREE SWEPTBACK WINGS HAVING AN ASPECT RATIO
OF 4 AT TRANSONIC SPEEDS
By Vernard E. Lockwood
SUMMARY
The damping-in-roll characteristics of three wings having an aspect
ratio of 4, a taper ratio of o.6, an NACA 65A006 airfoil section, and
sweep angles of 00, 350, and 450 have been determined through a Mach
number range from 0.6 to 1.15 and an angle-of-attack range from 00 to
approximately 70. The data were obtained from the Langley 7- by 10-foot
tunnel transonic bump by utilizing the twisted-wing technique.
The damping in roll showed a variation with Mach number similar to
that of the lift-curve slope; that is, an increase in magnitude of the
damping with increase in Mach number in the subsonic range was followed
by an appreciable loss through a Mach number of 1.0. Positive damping
(negative damping coefficient) was evident for all conditions investi-
gated. At all Mach numbers the damping decreased with increase in sweep
angle and at subsonic Mach numbers the variation with sweep was similar
to that predicted by theory. The results of the present investigation
agreed quantitatively with the results of a free-roll investigation at
subsonic Mach numbers on a series of similar wings.
INTRODUCTION
One phase of the National Advisory Committee for Aeronautics tran-
sonic research program has been the determination of the control
characteristics of flap-type controls throughout the transonic-speed
range. The basic control data-for a series of wings of aspect ratio 4
are reported in references 1 to 4. In order to determine the rolling
effectiveness of these controls, knowledge of the damping in roll of
the wings throughout the speed range is necessary. There have been
theoretical approaches made to the problem at subsonic speeds (refer-
ence 5) and at supersonic speeds (reference 6). These theories do not
UNCLASSIFIED
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Lockwood, Vernard E. Effects of sweep on the damping-in-roll characteristics of three sweptback wings having an aspect ratio of 4 at transonic speeds, report, December 14, 1950; (https://digital.library.unt.edu/ark:/67531/metadc58833/m1/2/: accessed March 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.