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National Advisory Committee for Aeronautics, Research Memorandum - Effect of Windshield Shape of a Pilot's Canopy on the Drag of an NACA RM-2 Drag Research Model in Flight at Transonic Speeds

Results of flight tests of an RACA RM—2 drag research model equipped
with a pilot's canopy having a vee windshield are presented for. a Mach
number range from 0.75 to 1.1L3. Comparison is made with test results of
a similar canopy having a flat windshield. The vee—windshield canopy
produced lower drag—coefficient values than the flat-windshield canopy
for Mach numbers from 0.85 to about 1.2. From M = 1.2 to 1.11- both
canopies produced the same drag coefficient.

Flight tests have been conducted at the NASA Pilotless Aircraft
Research Test Station, Wallops Island, Va. , to determine the drag of
KACA RM—2 drag research models equipped. with a pilot's canopy having a
vee—type windshield. Data have been obtained from previous tests of
" similar models having flat windshields. These canopies ware similar to
those used .on present—day, high—speed aircraft and. had a fineness ratio
of about 7.0, based on maximml width, and added about 10 percent to the
maximum frontal area of the basic RM—2 body. Results of tests of the
flat—windshield—canopy arrangement have been reported in reference 1.
There are herein presented data obtained fiom tests of two models of
the vee—windshield—canopy arrangement for a Mach number range from 0.75
to 1.43 which corresponds to a range of Reynolds number, based on over—
all body length (61I- 111.), from 22 to 50 million. Details of the basic
body and the flat—windshield canopy have been presented in reference 1.
A general—arrangement drawing of the basic body equipped with the vee—
type—windshield canopy is presented in figure 1. A comparison of the
two canopy types is presented in figure 2.

For comparison the faired curve of figure 3 is replotted in figure A
together with the curves presented in referenced. Since the drag coeffi—
cients are based on a constant area, figure It is fundamentally a comparison
of the drag forces experienced. by each of the three models.