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National Advisory Committee for Aeronautics, Technical Notes - Navy Propeller Section Characteristics as Used in Propeller Design

This report contains artificial aerodynamic characteristics
of a set of propeller sections to be used in designing prepel—
lers by means of the blade element theory. Characteristics com-
puted from model propeller tests for a single section are ex—
tended to cover sections of all thicknesses by means of model
wing tests on a series of Navy propeller sections at high Rey—
nolds Number in the variable density tunnel of the National
Advisory Cmnnittee for Aeronautics.

Designing prepellers by means of the blade element theory .
requires the knowledge of aerodynamic characteristics which tru—
ly represent the airfoil sections. Airfoil characteristics ob—
}tained from wind tunnel model wing tests are often used for
lack of better information. These, however, are not directly
applicable to segments of revolving propeller blades. Better
results are obtained by using characteristics that have been
calculated from model prepcller tests. Such characteristics have
been determined for a limited number of sections (Reference 3).

They are extended to cover sections of all practicable
thicknesses by means of model wing tests on a series of Navy
pr0peller sections {Reference 1).

These tests were made in the variable density wind tunnel
of the National Advisory Committee for Aeronautics. The sec—
tions were tested at two tank pressures, one atmosphere and
twenty atmOSpheres, the Reynolds Number at the latter pressure
corresponding to about the maximum found in propellers. The
shapes of all the sections are derived from a standard curve
(Fig. 5) in such a manner that the ratio of correSponding ordi—
nates to the maximum ordinate remains the same. The cambers or
maximum ordinates in terms of the chord of the six sections
tested were, .04, .08, .10, .13, .16 and .20. These cover the
range of flat faced sections usually found in propellers. A
camber of .04 is slightly less than is used in the thinnest
metal propellers at the present time, and .20 is about the cam—
ber usually found at half.the radius in wooden propellers.