The Functional Application of the Propeller Load Curve for Fixed Pitch Propellers

This thesis attempts to help the flight test community by using the propeller load curve (also known as prop load) to find brake horsepower (BHP) easily with only a propeller tachometer. This thesis also covers the equation for the propeller load curve.

The flight test was done using a Piper Cherokee 180 equipped with a Lycoming 0-360-A3A engine. The flight test data were collected at University of Tennessee Space Institute (UTSI). This data were then compared to the prop load from the engine manufacturer.

Based on the result of this flight test, using the prop load equation from the Lycoming will result in BHP that is within 96% agreement to the flight test BHP. The result of the test will also show that the equation for the propeller load curve at sea level is HP = K × (RPM³) where K = constant (Aircraft 1949). This thesis will also prove that if you are not at sea level, the equation then becomes HP = (√σ × K × RPM³) where σ = the atmospheric density ratio.

Recommendations include additional tests with multiple engines on a test stand.