Observation of laminar flow on an air-launched 15 degree cone-cylinder at local Reynolds numbers to 50 x 10(exp 6) at peak Mach number of 6.75 Page: 4 of 34
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NACA RM E56L03 3
Figure 3 shows the booster assembly, which consisted of a thin-wall
(1/16-in.) aluminum tube with cruciform aluminum fins mounted at the
rear. The fins were 1/4 inch thick, with the leading edges tapered and
rounded to a 1/16-inch radius. The booster rocket (T-40), which was
housed within the aluminum shell, was maintained at a temperature of
1000 F before firing by wrapping it with an electric blanket. The sus-
tainer rocket was not heated before launching.
The booster assembly was rigidly connected to the final stage with
a coupling that was destroyed by the ignition of the final-stage rocket.
4 The coupling was developed by the NACA Langley laboratory and is de-
scribed in reference 5. Table I gives some physical information on the
two-stage test body. Table II.presents data on the two rockets used.
The test body was carried aloft by the F2H-2B airplane shown in
figure 4. The model was launched 270 downward at an altitude of 43,360
feet. Time-delay squibs were used to ignite both rockets, and the test
o body was tracked by ground radar and phototheodolite equipment.
H The calculation procedure used in these flight tests is detailed in
references 2 and 4. The free-stream velocity was determined from radar
measurements and by integrating the acceleration data. The altitude was
obtained from radar measurements and the static-pressure measurement at
station 29.88. The variation of ambient pressure and temperature with
altitude was determined from a radiosonde survey made immediately fol-
lowing the flight.
The local flow conditions for this test body were computed for two
cases. Case I assumed that the nose of the model was sharply pointed
and that the flow along the cone-cylinder was represented by the calcu-
lations of references 6 and 7 as applied to the specific configuration
of this test. The flow properties of case I are designated "sharp-tip"
The local flow properties computed for case II are designated
"blunt-tip" conditions. Case II attempts to account for tip bluntness
effects by using the method of reference 8. This assumes that the sur-
face static pressure along the body, downstream of the blunted tip, is
the same as for a sharply pointed body. By assuming a normal-shock total-
pressure loss at the nose, the air in a small annular area about the body
is at a much lower Mach number than that of the sharply pointed body.
This layer of low Mach number air blankets the boundary layer. The
amount of tip blunting, of course, determines the length of boundary
layer that may be affected. Approximate calculations based on reference
8 indicate that the tip bluntness of the present test vehicle was insuf-
ficient to completely cover the boundary layer over the entire body.
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Rabb, Leonard & Krasnican, Milan J. Observation of laminar flow on an air-launched 15 degree cone-cylinder at local Reynolds numbers to 50 x 10(exp 6) at peak Mach number of 6.75, report, March 4, 1957; (digital.library.unt.edu/ark:/67531/metadc63393/m1/4/: accessed December 10, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.