Granted Patent B2

US 8,998,127 · App. 13/334,261 · Granted Apr 7, 2015

Inventor: Walter Gerd Oskar Sonneborn (Colleyville, TX)

Assignee: Groen Brothers Aviation, Inc.

B64C27/025B64C27/18B64C27/26

Abstract

Claims (50)

1. A method for reducing the ground roll of a rotorcraft landing in autorotation, the method comprising:

selecting a rotorcraft comprising at least one engine and a rotor;

executing, by the rotorcraft, a flight comprising a first portion, second portion, and third portion, the first portion immediately preceding the second portion, the second portion immediately preceding the third portion;

flying, during the first portion, the rotorcraft with the rotor exclusively in autorotation;

flying, during the second portion, the rotorcraft with rotation of the rotor being powered at least partially by the at least one engine;

flying, during the third portion, the rotorcraft with the rotor exclusively in autorotation;

terminating simultaneously the flight and the third portion with a touchdown of the rotorcraft; and

increasing, during the second portion, the rotational speed of the rotor.

2. The method of claim 1 , wherein the rotorcraft further comprises a prerotation system.

3. The method of claim 2 , further comprising prerotating, by the at least one engine via the prerotation system, the rotor prior to the executing of the flight.

4. The method of claim 3 , wherein the flying during the second portion comprises powering, by the at least one engine via the prerotation system, rotation of the rotor.

5. The method of claim 4 , further comprising increasing, during the second portion, the rotational speed of the rotor.

6. The method of claim 5 , wherein the increasing comprises increasing the rotational speed of the rotor to substantially the maximum value permitted for safe operation of the rotorcraft.

7. The method of claim 1 , wherein the flying during the third portion comprises:

approaching a landing site corresponding to the touchdown; and

bringing to substantially zero the ground speed of the rotorcraft with respect to the landing site.

8. The method of claim 7 , wherein the bringing comprises flaring the rotor.

9. The method of claim 8 , wherein:

the rotor comprises a plurality of rotor blades; and

the bringing further comprises increasing the angle of attack of each rotor blade of the plurality of rotor blades.

10. A method for reducing the ground roll of a rotorcraft landing in autorotation, the method comprising:

selecting a rotorcraft comprising at least one engine and a rotor;

executing, by the rotorcraft, a flight comprising a first portion, second portion, and third portion, the first portion immediately preceding the second portion, the second portion immediately preceding the third portion;

flying, during the first portion, the rotorcraft with the rotor exclusively in autorotation;

increasing, during the second portion, the rotational speed of the rotor to a value of substantially the maximum value permitted for safe operation of the rotorcraft;

flying, during the third portion, the rotorcraft with the rotor exclusively in autorotation;

and terminating simultaneously the flight and the third portion with a touchdown of the rotorcraft.

11. The method of claim 10 , wherein the rotorcraft further comprises a prerotation system.

12. The method of claim 11 , further comprising prerotating, by the at least one engine via the prerotation system, the rotor prior to the executing of the flight.

13. The method of claim 12 , wherein the increasing comprises urging, by the at least one engine, via the prerotation system, rotation of the rotor.

14. The method of claim 10 , wherein the increasing comprises increasing blade loading on the rotor.

15. The method of claim 10 , wherein the flying during the third portion comprises:

approaching a landing site corresponding to the touchdown; and

bringing to substantially zero the ground speed of the rotorcraft with respect to the landing site.

16. The method of claim 15 , wherein the bringing comprises flaring the rotor.

17. The method of claim 16 , wherein:

the rotor comprises a plurality of rotor blades; and

the bringing further comprises increasing the angle of attack of each rotor blade of the plurality of rotor blades.

18. The method of claim 10 , wherein the terminating comprises landing the rotorcraft with substantially no forward roll.

19. A method comprising:

selecting a rotorcraft comprising at least one engine, a prerotation system, and a rotor;

prerotating, by the at least one engine, via the prerotation system, the rotor;

executing, by the rotorcraft, after the prerotating, a flight comprising a first portion, second portion, and third portion, the first portion immediately preceding the second portion, the second portion immediately preceding the third portion;

flying, during the first portion, the rotorcraft with the rotor operating exclusively in autorotation;

flying, during the second portion, the rotorcraft with rotation of the rotor being powered at least partially by the at least one engine via the prerotation system;

increasing, during the second portion by the at least one engine via the prerotation system, the rotation speed of the rotor;

flying, during the third portion, the rotorcraft with the rotor exclusively in autorotation;

approaching, during the third portion, a landing site; and

bringing, during the third portion, to substantially zero, the ground speed of the rotorcraft with respect to the landing site; and

terminating simultaneously the flight and the third portion by landing the rotorcraft on the landing site with substantially no forward roll.

Assignments (12)

Continuity (100)