ESDU PERF ED1/1
Approximate estimation of drag of windmilling propellers.
Abstract:ESDU Perf ED1/1 gives graphs of power and thrust coefficient for propellers with activity factors of 350 and zero-lift angle at 0.7 radius of 3.1 degrees; guidance is given on estimating those parameters for any propeller and on adjusting values read from the curves so that they apply in that case. To use the curves the blade angle at 0.7 radius is required and for piston engines that will be defined by the flight fine pitch stop; another graph provides a means of estimating that. For turbine engines additional protection may be necessary. The motoring power of the engine is required to determine the windmilling speed for equilibrium and the drag is then obtained for that speed from the thrust curves.
|Data Item ESDU PERF ED1/1|