Nr Fairy, if there is upwards flow through the rotor system, then the angle of attack of flat pitch blades is positive. Negative blade pitch would help reduce the blade angle of attack. . .. .I fly an H46 and just recently oversped the rotor in an auto because I had collective was in the spring loaded detent. Won't bother going into the way, lets just say I fouled up with a little help from my friends.. .. .As to the original question, yes. Types are all different, but unrecoverably low Nr is a possible outcome.. . . . <small>[ 22 March 2002, 00:51: Message edited by: heedm ]</small>