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• August 25, 2016 Create Date
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National Advisory Committee for Aeronautics, Report - Full Scale Wind Tunnel Tests with a Series of Propellers of Different Diameters on a Single Fuselage

Aerodynamic tests were made with four geometrically
simdar metal propellers of diferent diameters, on G
Wright “ Whirlwind ” Jab’ engine in an open cockpit
fuselage. The tests mre made in the Twenty-Foot
Propeller Research Tunnel "of the National Advisory
Committee for Aeronautics. The results show little
diference in the characteristics of the various propellers,
the only one of any importance being an increase of
efioiency of the order of I per cent for a 5 per cent
increase of diameter, within the range of the tests.

This investigation was made in order to obtain
practical information regarding one phase of the
problem of the mutual interference between aircraft
propellers and the bodies on which they are mounted,
i. e., the efiect of the size of the propeller with respect
to the body.

Many model tests have been made involving pro-
peller-body interference but in nearly all cases ideal-
ized bodies of simple shape have been used, and so,
while the results are interesting in that they indicate
general tendencies, they have little quantitative value
when applied directly to actual aircraft. In the pres-
ent tests a full-sized open cockpit fuselage with a. 200
horsepower radial air-cooled engine was used along
with four metal propellers varying in diameter from
8 feet 11 inches to 10 feet 5 inches. The results are
therefore considered directly applicable to aircraft
conditions in which similar bodies and propellers are
used.

The tests were made in the Twenty-Foot Propeller
Research Tunnel of the National Advisory Committee
for Aeronautics.

The propeller blades and hub used in this investi—
gation were furnished by the Navy Department. The
blades were made of aluminum alloy, according to the
drawings in Figures 1, 2,3, and 4. The blades were all
geometrically similar except that they were all made to
fit the same hub.