Patent ID: 8469306

Claim:
A vertical takeoff and landing (VTOL), electrically-powered, winged aircraft, comprising: first and second tiltable nacelles disposed on a left wing and a right wing of the aircraft, respectively, each of the first and second nacelles configured to tilt with respect to the left and right wing, respectively; first and second sets of electric motors disposed in the respective first and second nacelles; first and second rotors mounted on the first and second nacelles, respectively, the first and second electric rotors configured to collectively produce a thrust force counter to a weight of the aircraft; at least one electrical energy store coupled simultaneously and separably to each motor of the first and second sets; wherein the at least one electrical energy store is configured to provide sufficient energy such that the aircraft is capable of achieving hover-out-of-ground-effect (HOGE) for a period of at least four minutes while one of the motors of the left or right set is inoperative, and while the aircraft carries a payload of at least 300 pounds; wherein the first rotor has a maximum tip speed of less than Mach 0.7 M at sea level in a standard atmosphere; and wherein the aircraft lacks a cross shaft coupling the electric motor set or rotor of the first or second nacelle to the electric motor set or rotor of the other nacelle, wherein the aircraft lacks a shifting gearbox between each of the first and second electric motor sets and its respective rotor, and wherein the aircraft has a maximum disk loading of less than 15 lbs/sq ft.