Why does the thrust available in the fixed pitch propeller thrust graph increasing and then decreasing?
assuming the other aixs of the graph is the RPM of engine/propeller, to the left of the optimal thrust the pitch is too steep (the propeller is too “heavy”) and to the right (into the increasing rpm) the propeller passed its efficiency peak. that’s why automatic propellers lower the pitch at low RPM (to make it easier for the engine to accelerate) and increase the pitch once RPM increase to keep the propeller (and engine, too) in the most efficient RPM.
