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National Advisory Committee for Aeronautics, Technical Notes - Propeller Design Extension of Test Data on a Family of Model Propellers by Means of the Modified Blade Element Theory - II

This report is the second of a series of four on propeller
design, and describes the method used to extend the data ob—
tained from tests on a family of thirteen model propellers to
include all propellers of the same form likely to be met in
practice. This necessitates the deve10pment of a method of
propeller analysis which when used to calculate the powers and
efficiencies gives results which check the tests throughout
thei range. Airfoil characteristics are derived from the
mode:Xpropeller tests themselves and used in the single section
method of analysis (given in the first of this series? N.A.G.A.
Technical Note Not 255) to calculate the powers and efficieny
else for prepellers outside of the test range.

N.A.C.A- Technical Report No. 237, entitled "Tests on Thir—
teen Navy Type Model Propellers," by W. F. Durand, gives the
test data on a family of thirteen Navy model wood prOpcllers.

These tests are the basis of the Navy design system.
The terms used in describing propellers of Navy form are
given in Table I.

In the family of models tested the basic series consisted
of seven prepellers, each having an aspect ratio of 8 and a
camber ratio of l, but with pitchediameter ratios varying from
.5 to 1.1. Variations of aSpect ratio and camber ratio were
made at a pitehrdiameter ratio of .7 only. The aspect ratios ,
tested were 5, 6, 8.5, and 7.5, each with a camber ratio of.l.
The camber ratios were 1, 1.1, 1.8, and 1.3, each with an es~
pect ratio of 6.