<DOC>
<DOCNO>
1339
</DOCNO>
<TITLE>
calculation of flutter characteristics for finite-span swept or unswept
wings at subsonic and supersonic speeds by a modified strip analysis .
</TITLE>
<AUTHOR>
yates, e.c.
</AUTHOR>
<BIBLIO>
naca rm l57l10, 1958 .
</BIBLIO>
<TEXT>
a method has been developed for calculating flutter characteristics of
finite-span swept or unswept wings at subsonic and supersonic speeds .
the method is basically a rayleigh type analysis and is illustrated with
 uncoupled vibration modes although coupled modes can be used . the
aerodynamic loadings are based on distributions of section lift-curve
slope and local aerodynamic center calculated from three-dimensional
steady-flow theory . these distributions are used in conjunction with
the /effective/ angle-of-attack distribution resulting from each of the
assumed vibration modes in order to obtain values of section lift and
pitching moment . circulation functions modified on the basis of loadings
for two-dimensional airfoils oscillating in a compressible flow are
 employed to account for the effects of oscillatory motion on the magnitudes
and phase angles of the lift and moment vectors .
flutter characteristics have been calculated by this method for 12 wings
 of varying sweep angle, aspect ratio, taper ratio, and center-ofgravity
position at mach numbers from 0 to as high as 1.75 . comparisons
 of the results with experimental flutter data indicate that this method
 gives generally good flutter results for a broad range of wings .
</TEXT>
</DOC>
