Nick,. .. .Thanks for the clear and elaborate coverage of 'Hub Springs', plus the concerns you brought up. . .. .The Ultralight craft must weigh 254 lbs or less, therefore it will be impossible to add the additional strength (and related weight) required to give any reasonable amount of 'hub spring' induced control moment to the fuselage. The weight of the rotor disk is a small portion of a craft's gross weight. I wonder if it might be possible to add just a small amount of 'hub spring', thereby at least controlling the moments of an unloaded rotor disk and providing a degree of safety? . .__________________. .. .Heedm,. .. .Perhaps the aerodynamic load that you mention might be a positive, since it is the force that is providing the faster response to the control input. We all three seem to be in agreement, that the weight penalty will be humongous for any significant amount of 'forced rotation'.. .. .The initial thinking was directed at an operational rotor. The elimination of the droop stops was sort of a freebie, just like Sprocket's idea regarding the elimination of tie-downs.. .. .Best that we leave Robinson out of this thread <img border="0" title="" alt="[Smile]" src="smile.gif" /> ; but your idea would make for an interesting discussion on a separate thread.. . . . <small>[ 11 March 2002, 22:38: Message edited by: Dave Jackson ]</small>