Math / Physics
Stits Playboy Proj
The propeller's pitch has a significant effect on the required engine power! As the propeller (with high-pitch) rotates faster it begins to stall. This causes higher drag from turbulence which consumes engine power and reduces thrust. In the real world the engine cannot rotate a stalled prop as fast as a lower-pitch prop. The program compensates for this by increasing the required power (or vice versa)!
The static thrust will always be less on the ground then while flying. This is because there is about a 20% loss of efficiency due to air stream slippage. Once in the air and forward motion is attained, the propeller becomes more efficient. The tip speed of the propeller blades is also very important! It should never be higher than the standard supersonic limit (approx. 320 m/s). The supersonic speed causes the blades to take a very high load due to the special airflow waves generated by the subsonic and supersonic changes!
The goal is to find the optimal propeller configuration that uses the maximum engine power AND the tip speed is not faster than 230 m/s AND gives enough thrust AND produces enough flying speed.
The calculator can not check the reliability of the entered data therefore all inputs need to be real world value ranges. Testing is always needed that the real engine propeller combination are realistic.