Purebred and Hybrid Electric VTOL Tilt Rotor Aircraft

Abstract

Electrically powered Vertical Takeoff and Landing (VTOL) aircraft are presented. Contemplated VTOL aircraft can include one or more electrical energy stores capable of delivering electrical power to one or more electric motors disposed within one or more rotor housings, where the motors can drive the rotors. The VTOL aircraft can also include one or more sustainer energy/power sources (e.g., batteries, engines, generators, fuel-cells, semi-cells, etc.) capable of driving the motors should the energy stores fail or deplete. Various VTOL configurations are presented including an all-battery purebred design, a light hybrid design, and a heavy hybrid design. The contemplated configurations address safety, noise, and outwash concerns to allow such designs to operate in built-up areas while retaining competitive performance relative to existing aircraft.

What is claimed is: 
     
         1 . A vertical takeoff and landing (VTOL) heavier than air aircraft, comprising:
 at least a first electric motor coupled to a first rotor configured to produce a thrust force counter to a weight of the aircraft;   at least one electrical energy store coupled to at least the first electric motor; and   wherein the aircraft is capable achieving hover-out-of-ground-effect (HOGE) for a period of at least four minutes while the first electric motor drives the first rotor to produce the thrust, and while the aircraft carries a payload of at least 50 pounds.   
     
     
         2 . The aircraft of  claim 1 , wherein the electrical energy store comprises a rechargeable battery. 
     
     
         3 . The aircraft of  claim 2 , wherein the rechargeable battery is repositionable within the aircraft for center of gravity adjustment. 
     
     
         4 . The aircraft of  claim 1 , further comprising at least one sustainer energy source configured to generate electricity to power the first electric motor to drive the rotor. 
     
     
         5 . The aircraft of  claim 4 , wherein the sustainer energy/power source comprises at least one of the following: a fuel driven engine with a generator, a fuel cell, and a semi-cell. 
     
     
         6 . The aircraft of  claim 4 , wherein the at least one energy store is configured to be recharged from the sustainer energy/power source. 
     
     
         7 . The aircraft of  claim 1 , wherein the at least one electrical energy store is configured to deliver at least 100 W-hrs/kg. 
     
     
         8 . The aircraft of  claim 1 , wherein the aircraft is capable of flight to a range of at least 200 nautical miles without requiring non-stored electrical sustainer power. 
     
     
         9 . The aircraft of  claim 1 , wherein the payload is at least 3,500 pounds. 
     
     
         10 . The aircraft of  claim 1 , wherein the first rotor has a maximum tip speed of less than Mach 0.7 M at sea level in a standard atmosphere. 
     
     
         11 . The aircraft of  claim 1 , wherein aircraft has a maximum disk loading of less than about 15 lbs/sq ft. 
     
     
         12 . The aircraft of  claim 1 , wherein the aircraft is unmanned. 
     
     
         13 . The aircraft of  claim 1 , wherein the first rotor is tiltable. 
     
     
         14 . The aircraft of  claim 13 , further comprising a sustainer energy/power source configured to retain a preferred orientation relative to a main body of the aircraft as the rotor tilts. 
     
     
         15 . The aircraft of  claim 1 , further comprising a second electric motor coupled to the at least one electrical energy store, where the second electric motor is coupled to a second rotor. 
     
     
         16 . The aircraft of  claim 15 , wherein the first electric motor is coupled to the second rotor and is configured to drive the second rotor upon failure of the second electric motor. 
     
     
         17 . The aircraft of  claim 16 , wherein the aircraft is capable of achieving HOGE where one of the first and second electric motors is inoperative. 
     
     
         18 . The aircraft of  claim 15 , wherein the first and the second electric motors are housed in respective first and second nacelles, where the first and second nacelles each house a plurality of electric motors, and where each motor of the nacelle is sized and configured to allow the aircraft to sustain HOGE after failure of the first or the second electric motors. 
     
     
         19 . The aircraft of  claim 15 , wherein the aircraft lacks a cross shaft coupling the motors to the rotors. 
     
     
         20 . The aircraft of  claim 15 , wherein the aircraft lacks a shifting gearbox. 
     
     
         21 . The aircraft of  claim 1 , wherein the aircraft is capable of achieving HOGE while generating less than 40 dB of sound as measure by an observer on the ground 1,500 feet away from the aircraft. 
     
     
         22 . The aircraft of  claim 1 , wherein the at least one electrical energy store is field replaceable.