The zero-lift drag of a slender body of revolution (NACA RM-10 research model) as determined from tests in several wind tunnels and in flight at supersonic speeds Page: 4 of 14

                                
REPORT 1160--NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

(a)

Support

shield

Strain-gage

Model

(b)                                        Floating

Flexure wire
supports

(a) Internal strain-gage balance; 4- by 4-foot tunnel (representative of arrangement in 8- by 6-foot tunnel).
(b) Strain-gage balance external to model; 9-inch tunnel (representative of arrangement in 1- by 3-foot tunne:).
FIGURE 4.--Sketch of model mounting and internal and external balance systems.

grains located X inch back from the model nose and about
Y inch wide in the direction of flow.
The ratio of the sting to base diameter for the 50-inch
model was 0.579. This ratio for the 42.05-inch force and
pressure models was 0.36 and 0.60, respectively.
Range of tests.-Total drag of the body, base drag, and
the body skin friction drag were measured on the 50-inch
model at a Mach number of 1.6 for a range of Reynolds
number from 2X101 to 40X10". The tests were made at
zero angle of attack with natural and fixed transition without
tail fins attached.
The tests with the 42.05-inch body consisted of measure-
ment of the forebody pressure distribution at a Mach number
of 1.59 for Reynolds numbers between 1.8X100 and 4.5X106.
The 42.05-inch model was also tested with tail fins attached.
8- BY 6-FOOT SUPERSONIC TUNNEL AND MODEL
The Lewis 8- by 6-foot tunnel is a rectangular, closed-
throat, nonreturn-type wind tunnel. The results reported
herein were obtained on two models which had body lengths
of 73 inches. One model was used to obtain strain-gage
measurements of total drag and was instrumented to obtain
base pressure measurements with and without the stabilizing
fins attached. The second model was used to obtain the
forebody pressure drag and slkin friction drag.
Model construction.-The model bodies were spun from
aluminum sheet and the noses of the bodies were blunted by
removing Y3 inch from the pointed tip. There was some
deviation of the actual pressure-model contour from the
calculated dimensions of the model. The deviation was
relatively large (0.032 inch undersize) at a station 20 inches

behind the model nose and was of the order of 0.01 inch over
the remainder of the body except for a small portion near
the base which was 0.02 inch undersize. No surface rough-
ness measurements are available for these models.
Model instrumentation.--One model was rigidly connected
to a three-component strain-gage balance located inside the
body and the balance was attached to the tunnel sting-strut
combination (fig. 4 (a)). T he strain-gage balance measwmed
the total drag of the model.
Base pressure was measured at orifices on the model base
located at -450 to each of the rows of body surface pressure
orifices and at a radius of 1.624 inches as shown in figure 2 (b).
The pressure model was sting mounted on an internal cam
mechanism which allowed the model to be remotely rotated
to determine the circumferential variation of the pressure
distribution.
The forebody pressure drag was determined from   the
pressure distribution measured by two diametrically opposite
rows of pressure orifices consisting of 23 orifices each.
Boundary-layer profiles were determined by diametrically
opposite rakes extending 1% inches into the stream in the
plane of the model base.
The ratio of sting to base diameter was 0.66.
Range of tests.-The tests were conducted at values of
Reynolds number of 29.1, 29.2, 29.5, and 31.1X106 for
Mach numbers of 1.49, 1.59, 1.78, and 1.98, respectively.
9-INCH SUPERSONIC TUNNEL AND MODEL
The Langley 9-inch tunnel is a rectangular, closed-throat,
closed-circuit-type, variable-density  wind  tunnel. The

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