Propeller blade element momentum theory is a first-order method commonly used to analyze propeller performance. Blade element theory discretizes the rotor, analyzes aerodynamic forces acting on each element, and requires only a rudimentary description of the blade geometry. Blade element theory alone lacks the ability of predicting the propeller-induced inflow velocity needed to complete the flowfield description. The flow model is completed using concepts from momentum theory, which assumes a single continuous axisymmetric flow-through rotor disk. The traditional method used to solve the blade element momentum equations assumes a small local angle of attack at all sections along the blade and that local induced drag negligibly reduces the local propeller thrust coefficient. These assumptions, while allowing a closed form solution to be obtained, are known to be inaccurate at high advance ratios and along the inner half-span of the blade. An alternative nonlinear, numerical solution method thatavoidstheseinaccuratesimplifyingassumptionsispresented.Solutionmethodsarecomparedformultiplepitch anglesandadvanceratios.Solutionsarecomparedwiththrustandpowercoefficientdatacollectedfromwind-tunnel testsofsmallradio-controlaircraftpropellers.Thenonlineartheorycorrectionsbetterrepresentmeasuredpropeller performance, especially at high advance ratios.
[1]
Michael S. Selig,et al.
Propeller Performance Data at Low Reynolds Numbers
,
2011
.
[2]
A. M. Kuethe,et al.
Foundations of aerodynamics: bases of aerodynamic design
,
1986
.
[3]
S. Goldstein.
On the Vortex Theory of Screw Propellers
,
1929
.
[4]
Barnes W. McCormick,et al.
Aerodynamics of V/STOL flight
,
1967
.
[5]
S. C. M. Yu,et al.
Unsteady Aerodynamic Investigation of the Propeller-Wing Interaction for a Rocket Launched Unmanned Air Vehicle
,
2013
.
[6]
Warren F. Phillips,et al.
Mechanics of Flight
,
2004
.
[7]
C. L. Tibery,et al.
TABLES OF THE GOLDSTEIN FACTOR
,
1964
.