Rotorcraft Tip Mach Numbers

The tip Mach number has been computed from the rotor’s speed and the maximum speed at sea level, except for the Boeing-Sikorsky RAH-66 Comanche, for which the maximum absolute speed was used (data at S/L not available). This change is partially reflected by the fact that the operation point of this vehicle is somewhat shifted toward the highest performances.

The operation point for the Bell-Boeing V-22 Osprey has been computed for the helicopter mode (u = 185 km/h).

The dashed line is a linear fit of all the available data.