SYSTEM AND METHOD FOR IMPROVING TRANSITION LIFT-FAN PERFORMANCE

• US 20130140404A1
• Filed: 12/05/2011
• Published: 06/06/2013
• Est. Priority Date: 12/05/2011
• Status: Active Grant

• Current Assignee: Aurora Flight Sciences Corporation (The Boeing Co.)
• Original Assignee: Aurora Flight Sciences Corporation (The Boeing Co.)
• Inventors: Parks, Robert
• Granted Patent: US 10,427,784 B2
• Time in Patent Office: Days
• US Class Current: 244/23.A
• CPC Class Codes: B64C 11/30 Blade pitch-changing mechanisms
• 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 29/0025 the propellers being fixed relative to the fuselage
• CPC Class Codes: B64C 29/0083 the lift during taking-off being created by several motors of different type
• CPC Class Codes: B64C 29/0091 Accessories not provided for elsewhere
• CPC Class Codes: B64D 27/24 using steam or spring force jet aircraft B64D27/16
• CPC Class Codes: G05D 1/102 specially adapted for vertical take-off of aircraft

Abstract

A system and method enabled to increase efficiency during a VTOL aircraft'"'"'s transition. A VTOL aircraft enabled to operate multiple lift fans arranged into separately controllable groups, wherein the VTOL aircraft initially has vertical flight but transitions to horizontal flight. A first group of lift fans may be kept at full throttle, a second group of lift fans may be throttled to balance thrust and/or weight, and a third group of lift fans may be shut off.

Claims

1. A propulsion system for increasing efficiency during a vertical take off and landing (VTOL) aircraft'"'"'s transition, comprising:

a plurality of lift fans arranged into three or more separately controlled groups, wherein the plurality of lift fans are used to transition a VTOL aircraft between vertical flight and horizontal flight;

wherein a first group of lift fans is kept at full throttle during transition;

wherein a second group of lift fans is throttled to balance thrust during transition; and

wherein a third group of lift fans is shut off during transition.

2. The system of claim 1, wherein at least one of the plurality of lift fans is throttled using one of the following throttling techniques:

(i) varying the fan'"'"'s RPM;

(ii) varying fan'"'"'s pitch;

or (iii) combinations thereof.

3. The system of claim 1, wherein the aircraft'"'"'s pitch and roll are trimmed by throttling the second group of lift fans.

4. The system of claim 1, wherein the aircraft has a disc loading of 50 lbs per square foot or less.

5. The system of claim 1, wherein the shut-off lift-fans are covered after being shut down to decrease aerodynamic drag on the VTOL aircraft.

6. The system of claim 1, wherein at least one of the plurality of lift fans has adjustable vanes to direct the fan exhaust flow aft, thereby providing thrust and reducing drag.

7. The system of claim 1, wherein the plurality of lift fans comprises six or more lift fans.

8. The system of claim 1, wherein the VTOL aircraft uses a hybrid of turbine and electric thrusting.

9. A method for increasing efficiency during a vertical take off and landing (VTOL) aircraft'"'"'s transition comprising:

providing a VTOL aircraft enabled to operate a plurality of lift fans arranged into three or more separately controlled groups, wherein the plurality of lift fans are used to transition a VTOL aircraft between vertical flight and horizontal flight;

maintaining a first group of lift fans at full throttle during transition;

throttling a second group of lift fans to balance thrust during transition; and

shutting off a third group of lift fans during transition.

10. The method of claim 9, wherein at least one of the plurality of lift fans is throttled using one of the following throttling techniques:

(i) varying the fan'"'"'s RPM;

(ii) varying fan'"'"'s pitch;

or (iii) combinations thereof.

11. The method of claim 9, wherein the aircraft'"'"'s pitch and roll are trimmed by throttling the second group of lift-fans.

12. The method of claim 9, wherein the aircraft has a disc loading of 50 lbs per square foot or less.

13. The method of claim 9, further comprising the step of covering a lift-fan after it has been shut down to decrease aerodynamic drag on the VTOL aircraft.

14. The method of claim 9, further comprising the step of placing adjustable vanes under one or more of the plurality of lift fans to direct the fan exhaust flow aft, thereby providing thrust and reducing drag.

15. The method of claim 9, wherein the plurality of lift fans includes six or more lift fans.

16. The method of claim 9, wherein the VTOL aircraft uses a hybrid of turbine and electric thrusting.

17. A vertical take off and landing (VTOL) aircraft having an increased efficiency during vertical takeoff and landing transitions, comprising:

a plurality of lift fans arranged into three or more separately controlled groups, wherein the plurality of lift fans are used to transition the VTOL aircraft between vertical flight and horizontal flight;

wherein a first group of lift fans is kept at full throttle during transition;

wherein a second group of lift fans is throttled to balance thrust during transition; and

wherein a third group of lift fans is shut off during transition.

18. The aircraft of claim 17, wherein at least one of the plurality of lift fans is throttled using one of the following throttling techniques:

(i) varying the fan'"'"'s RPM;

(ii) varying fan'"'"'s pitch;

or (iii) combinations thereof.

19. The aircraft of claim 17, wherein the aircraft'"'"'s pitch and roll are trimmed by throttling the second group of lift fans.

20. The aircraft of claim 17, wherein the disc loading value is 50 lbs per square foot or less.

21. The aircraft of claim 17, wherein the shut-off lift-fans are covered after being shut down to decrease aerodynamic drag on the VTOL aircraft.

22. The aircraft of claim 17, wherein at least one of the plurality of lift fans has adjustable vanes to direct the fan exhaust flow aft, thereby providing thrust and reducing drag.

23. The aircraft of claim 17, wherein the plurality of lift fans comprises six or more lift fans.

24. The aircraft of claim 17, wherein the VTOL aircraft uses a hybrid of turbine and electric thrusting.

25. A vertical take off and landing (VTOL) aircraft having an increased efficiency during vertical takeoff and landing transitions, comprising:

a plurality of lift fans arranged into three or more separately controlled groups, wherein the plurality of lift fans are used to transition the VTOL aircraft between vertical flight and horizontal flight, each group having a different throttle setting during transition.

26. The aircraft of claim 25, wherein, during transition, a first group of lift fans is kept at full throttle;

a second group of lift fans is throttled to balance thrust; and

a third group of lift fans is shut off.

27. The aircraft of claim 25, wherein at least one of the plurality of lift fans is throttled using one of the following throttling techniques:

(i) varying the fan'"'"'s RPM;

(ii) varying fan'"'"'s pitch;

or (iii) combinations thereof.

28. The aircraft of claim 25, wherein the aircraft'"'"'s pitch and roll are trimmed by throttling the second group of lift fans.

29. The aircraft of claim 25, wherein the shut-off lift fans are covered after being shut down to decrease aerodynamic drag on the VTOL aircraft.

30. The aircraft of claim 25, wherein the disc loading value is 50 lbs per square foot or less.

31. The aircraft of claim 25, wherein at least one of the plurality of lift fans has adjustable vanes to direct the fan exhaust flow aft, thereby providing thrust and reducing drag.

32. The aircraft of claim 25, wherein the plurality of lift fans comprises six or more lift-fans.

33. The aircraft of claim 25, wherein the VTOL aircraft uses a hybrid of turbine and electric thrusting.