stallfreepropellers.comFlow separation and turbulence over a blade shall be kept within limits for excellent performance.
A propeller working at its design speed produces optimal (maximal) efficiency. In this regime each blade-section (airfoil) of the propeller has one particular flow-pattern around it, which allows the best performance.
The ideal regulation system is expected to maintain this flow-pattern everywhere (around each section of each blade of the propeller), against changing flight conditions.
Smartness of a blade equals its ability to adopt to changing flight conditions. Different values of the axial speed are the main factors effecting flight conditions.
Today’s variable pitch propellers too have a degree of smartness. That means these propellers are capable to adopt to the new regime, when flight conditions (mainly axial speed) change – but only within a narrow margin.
Simultaneous Stall and Windmilling on The Same Blade – Happens Frequently, Undiscovered
Stallfree propellers have sophisticated blades. Both stall and windmilling regimes can be avoided – along the whole working radius, in a very wide range of axial speed.
