<DOC>
<DOCNO>
815
</DOCNO>
<TITLE>
investigation of several blunt bodies to determine
trans- onic aerodynamic characteristics including effects
of spinning and of extendible afterbody flaps and some
measurements of unsteady base pressures .
</TITLE>
<AUTHOR>
fisher,l.r. and dicamillo,j.r.
</AUTHOR>
<BIBLIO>
nasa memo 1-21-59l, 1959.
</BIBLIO>
<TEXT>
  several blunt bodies having shapes that may be suitable for atmospheric
reentry vehicles were tested to determine the aerodynamic characteristics
of such shapes for angles of attack up to 34 .  the tests
were conducted through the transonic mach number range and at reynolds
numbers from 1.74 x 10 to 2.78 x 10, based on body diameter .
  a full-skirted rather than a short-skirted type of shape developed
the greatest amount of static stability and the largest lift-curve
slopes .  the angle of attack for maximum lift for such bodies appears
to be subject to mach number effects .  spinning a full-skirted body
about its longitudinal axis generally increased the lift and reduced the
pitching moment at angles of attack and reduced the aerodynamic static
stability parameter through the transonic mach number range .  the extension
of segmented clamshell-shaped flaps from the afterbody of a
short-skirted model served to increase the lift and static stability
only if the flaps extended into the airstream .
  some evidence was found of oscillatory base pressures on two dissimilar
shapes at certain high angles of attack and the highest mach
number in these tests .  there is doubt, however, that these pressures
can induce any significant oscillatory motion for a reentry vehicle
because of their small amplitude and phasing .
</TEXT>
</DOC>
