Purebred and hybrid electric VTOL tilt rotor aircraft

• US 8,469,306 B2
• Filed: 01/26/2010
• Issued: 06/25/2013
• Est. Priority Date: 01/27/2009
• Status: Active Grant

• Current Assignee: Overair, Inc.
• Original Assignee: Ira F. Kuhn Jr
• Inventors: Kuhn, Ira F. Jr.
• Primary Examiner(s): Sanderson, Joseph W
• Application Number:
  US12/693,657
• Publication Number:
  US 20110024555A1
• Time in Patent Office: 1,246 Days
• Field of Search: 244/7.R, 244/7.C, 244/12.4, 244/17.11, 244/17.19, 244/17.23, 244/23.B, 244/53.R, 244/58, 244/60, 446/34, 446/36
• US Class Current: 244/12.4
• CPC Class Codes: B64C 29/0016 the lift during taking-off being created by free or ducted propellers or by blowers
• CPC Class Codes: B64C 29/0033 the propellers being tiltable relative to the fuselage
• CPC Class Codes: B64D 27/026 comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine Hybrid electric aircraft B64D27/33
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for 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.

Claims

1. 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.

2. The aircraft of claim 1, wherein the at least electrical energy store comprises a rechargeable battery having at least 2 KW/Kg power density and at least 100 W-hrs/kg usable energy density.

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, wherein the at least one electrical energy store is field replaceable.

5. The aircraft of claim 1, further comprising at least one sustainer energy source configured to generate sufficient electricity to (a) power the first and second sets of electric motors to drive the first and second rotors, respectively, such that the aircraft can climb above 4500 ft in altitude and have a cruise speed of at least 165 kts, and (b) at least partially recharge the at least one electrical energy store.

6. The aircraft of claim 5, wherein the at least one sustainer energy source is selected from the group consisting of (1) a second rechargeable battery having a usable energy density of at least 400 W-hrs/kg, (2) a second rechargeable battery and a fuel driven electric generator that sequentially supply power, where the second rechargeable battery has a usable energy density of at least 200 W-hrs/kg, and (3) a fuel driven engine with a generator.

7. The aircraft of claim 5, wherein the at least one sustainer energy source comprises a second rechargeable battery having a usable energy density of at least 400 W-hrs/kg, such that the aircraft is configured to fly at least 200 nautical miles at the cruise speed of 165 kts and at a altitude of at least 6,000 feet using only the second rechargeable battery.

8. The aircraft of claim 5, wherein the at least one sustainer energy source comprises a second rechargeable battery and a fuel driven electric generator that sequentially supply power, where the rechargeable battery has a usable energy density of at least 200 W-hrs/kg, such that the aircraft is configured to fly (a) at least 50 nautical miles at the cruise speed of 165 kts and at a altitude of at least 6,000 feet using only the second rechargeable battery, and (b) at least 650 nautical miles at the cruise speed of 210 knots and at an altitude of 18,000 feet using the fuel driven electric generator.

9. The aircraft of claim 5, wherein the at least one sustainer energy source comprises a fuel driven engine with a generator, such that the aircraft is configured to fly at least 1,200 nautical miles at the cruise speed of 300 kts and at a altitude of 37,000 feet using only the fuel driven engine with the generator.

10. The aircraft of claim 5, wherein the at least one electrical energy store is configured to be recharged from the at least one sustainer energy source.

11. The aircraft of claim 1, wherein the payload is 3,500 pounds.

12. The aircraft of claim 1, wherein the at least one sustainer energy source is further configured to retain a preferred orientation relative to gravity as the first and second nacelles tilt.

13. The aircraft of claim 1, wherein the aircraft is capable of achieving HOGE while generating less than 40 dB of sound as measured by an observer on the ground 1,500 feet away from the aircraft.