Tip Speed

The choice of tip speed for the tail rotor is usually based on just two conflicting considerations: a low tip speed minimizes noise, and a high tip speed minimizes weight. Aerodynamic factors are less important than they are on the main rotor. High tip speeds are not so likely to generate serious Mach tuck problems because the blades are stubbier and thus torsionally stiffer; and low tip speeds are not likely to produce retreating tip stall problems because the tail rotor operates in a nonpropulsive mode with a more benign angle of attack distribution. How designers have decided in the past is indicated by the tail rotor tip speeds used on contemporary helicopters as listed in Appendix B.