Comments

I'm an aeronautical Engineer by trade, in the rotary wing business. A couple of comments: The replacement of hydraulics with electric motors is probably in response to the V-22 lost when a hydraulic failure poured hydraulic fluid into the engine nacelle of the aircraft. A man I'd done some work with over the years died in that accident. Electric motors will remove the flammable fluid, but will be no less vulnerable to failure - you still have to have wiring to get power and control commands to the motors, and those are just as subject to damage as hydraulic lines. The hover rotor speed is no big secret. Any rotorcraft does this about the same way - calculate the drag-rise mach number for the blade (propeller) tips under the range of operating conditions, and keep the tip a certain percentage under that number. If you choose any higher tip speed, you lose efficiency to drag rise. Any lower, and you're not getting all the lift available from the rotor. It's this hover condition that sizes the rotor, not the tilted-forward, level-flight condition. Dan Schrage is one of the most respected minds in this business. If he's onboard, the concept is worth listening to.