Aircraft landing gear prerotation system

• US 5,104,063 A
• Filed: 04/27/1990
• Issued: 04/14/1992
• Est. Priority Date: 04/27/1990
• Status: Expired due to Fees

• Current Assignee: James M. Hartley
• Original Assignee: James M. Hartley
• Inventors: Hartley, James M.
• Primary Examiner(s): Peters, Jr., Joseph F.
• Assistant Examiner(s): Ellis, Christopher P.
• Application Number:
  US07/515,410
• Time in Patent Office: 718 Days
• Field of Search: 244/103 R, 244/103 S
• US Class Current: 244/103.00S
• CPC Class Codes: B64C 25/40 the elements being rotated before touch-down

Abstract

A device to induce rotation of aircraft landing wheels is disclosed, using only the force of oncoming air to bring them up to synchronous ground (landing) speed during approach to landing. A complete, independently operating system with its own sensors, microcontroller, motors and control linkages, which does not interface with any of the aircraft'"'"'s instumentation or systems, continually measures the actual ground speed of the aircraft during final approach, transmitting this flow of data to a microcontroller for continuous translation into required RPM for each tire diameter and monitors the precise RPM of each landing wheel through non-contact photo-tachometers whose outputs are multiplexed into the microcontroller. The system provides continuous control over the RPM of each landing wheel through air intake ducts with servo motor driven inlet vanes gating incoming air to the wheel-mounted impellers. An independent servo control loop for each wheel have their error signal and null point derived, through comparator logic and multiplexing, from the difference between instantaneous wheel RPM and ground-speed-based target RPM.

Claims

1. A system for prerotating an aircraft'"'"'s landing gear wheel prior to landing wherein the aircraft has at least one landing gear wheel attached to the aircraft by a support, comprising:

means for measuring the true ground speed of the aircraft independently from the aircraft'"'"'s airspeed;

means for rotating said wheel at selective revolutional speeds while the aircraft is airborn;

means for measuring said revolutional speeds of said wheel; and

control means for operating said means for rotating said wheel, said control means being responsive to said means for measuring the true ground speed and responsive to said means for measuring said revolutional speeds of said wheel, wherein said control means operates said means for rotating to selectively increased and decreased revolutional speeds of said wheel to correspond to the true ground speed, wherein said wheel has an impeller attached thereto, and wherein said means for rotating said wheel comprises a duct having a forward air intake and an air outlet, said outlet being directed towards said impeller to rotate said wheel, said duct having a variable gate therein to regulate airflow through said duct onto said impeller, said gate being openable by power means responsive to said control means, wherein said airflow through said duct and the rotational speed of said wheel is proportionally increased and decreased by respective opening and closing of said variable gate in response to said control means in relation to the true groud speed of the aircraft.

2. The system of claim 1 wherein said means for measuring said revolutional speeds of said wheel comprises a photoreflector on said wheel and a non-contact photosensor mounted apart from said wheel to generate an r.p.m. signal.

10. The system of claim 1 wherein said control means comprises a microprocessor operable to read ground speed signals from said means for measuring the true ground speed and r.p.m. signals from said means for measuring revolutional speeds, and wherein said microprocessor is programmed to send a control signal to said means for rotating said wheel responsive to said r.p.m. signal and to said ground speed signal.

11. The system of claim 1 wherein said support shortens under weight of landing the aircraft, and further comprising means for enabling the engaging and disengaging of a wheel brake connected to said support, wherein said wheel brake is engagable when said support is shortened under said weight, and wherein said wheel brake is not engagable when said support is not shortened by said weight.

12. The system of claim 11 wherein said variable gate comprises a pair of oppositely disposed hinged doors at said air intake and wherein said power means comprises an electric motor coupled to move gear means, said pair of doors being coupled to said gear means for opening and closing said pair of doors.

13. The system of claim 12 and further comprising a second, auxiliary means for measuring wheel revolutional speed for providing an independent, second r.p.m. signal.

14. The system of claim 1 wherein said means for measuring rotational speed of said wheel is coupled to a tachometer readout in the aircraft wherein the pilot may verify wheel rotation.

15. The system of claim 1 and further comprising a readout display for the aircraft pilot coupled to said control means having readouts for true ground speed readout, a target wheel r.p.m. readout as a function of said true ground speed, and a tachometer readout for actual wheel r.p.m.

9. A system for prerotating an aircraft'"'"'s landing gear wheel prior to landing, comprising:

at least one landing gear wheel attached to the aircraft by a support;

means for measuring the true ground speed of the aircraft independently from the aircraft'"'"'s airspeed;

means for rotating said wheel at selective revolutional speeds while the aircraft is airborn;

means for measuring said revolutional speeds of said wheel;

control means for operating said means for rotating said wheel, said control means being responsive to said means for measuring the true ground speed and responsive to said means for measuring said revolutional speeds of said wheel, wherein said control means operates said means for rotating to selectively increased and decreased revolutional speeds of said wheel to correspond to the true ground speed, wherein said wheel has an impeller attached thereto, and wherein said means for rotating said wheel comprises a duct having a forward air intake and an air outlet, said outlet being directed towards said impeller to rotate said wheel, said duct having a variable gate therein to regulate airflow through said duct onto said impeller, said gate being openable by power means responsive to said control means, wherein said airflow through said duct and the rotational speed of said wheel is increased by increased opening of said gate;

wherein said means for measuring the true ground speed comprises a Doppler radar unit on the aircraft.

3. The system of claim 9 wherein said means for measuring said revolutional speeds of said wheel comprises a photoreflector on said wheel and a non-contact photosensor mounted apart from said wheel to generate an r.p.m. signal.

4. The system of claim 3 wherein said control means comprises a microprocessor operable to read ground speed signals from said means for measuring the true ground speed and r.p.m. signals from said means for measuring revolutional speeds, and wherein said microprocessor is programmed to send a control signal to said means for rotating said wheel responsive to said r.p.m. signal and to said ground speed signal.

5. The system of claim 4 wherein said support shortens under weight of landing the aircraft, and further comprising means for enabling the engaging and disengaging of a wheel brake connected to said support, wherein said wheel brake is engagable when said support is shortened under said weight, and wherein said wheel brake is not engagable when said support is not shortened by said weight.

6. The system of claim 5 wherein said variable gate comprises a pair of oppositely disposed hinged doors at said air intake and wherein said power means comprises an electric motor coupled to move gear means, said pair of doors being coupled to said gear means for opening and closing said pair of doors.

7. The system of claim 6 wherein said means for measuring rotational speed of said wheel is coupled to a tachometer readout in the aircraft wherein the pilot may verify wheel rotation.

8. The system of claim 6 and further comprising a readout display for the aircraft pilot coupled to said control means having readouts for true ground speed readout, a target wheel r.p.m. readout as a function of said true ground speed, and a tachometer readout for actual wheel r.p.m.

16. A system for prerotating an aircraft'"'"'s landing gear wheel prior to landing wherein the aircraft has at least one landing gear wheel attached to the aircraft by a support, comprising:

means for rotating said wheel at selective revolutional speeds while the aircraft is airborn, wherein said wheel has an impeller attached thereto, and wherein said means for rotating said wheel comprises a duct having a forward air intake and an air outlet, said outlet being directed towards said impeller to rotate said wheel, said duct having a variable gate therein to regulate airflow through said duct onto said impeller, said gate being openable by power means responsive to control means for operating said means for rotating said wheel, wherein said airflow through said duct and the rotational speed of said wheel is increased by increased opening of said variable gate to selectively increase and decrease revolutional speeds of said wheel, wherein said variable gate comprises a pair of oppositely disposed hinged doors at said air intake and wherein said power means comprises an electric motor coupled to move gear means, said pair of doors being coupled to said gear means for opening and closing said pair of doors.

17. The system of claim 16 wherein said support shortens under weight of landing the aircraft, and further comprising means for enabling the engaging and disengaging of a wheel brake connected to said support, wherein said wheel brake is engageable when said support is shortened under said weight, and wherein said wheel brake is not engageable when said support is not shortened by said weight.

18. The system of claim 16 and further comprising means for measuring said revolutional speeds of said wheel comprising a light reflector on said wheel and a photo-receptive device to generate an r.p.m. signal based on light reflected from said reflector, said control means responsive to said r.p.m. signal.

20. The system of claim 16 wherein said gear means comprise a worm gear shafted to said motor and a second gear engaging said worm gear, wherein said second gear is coupled to a first sector gear secured to a first of said hinged doors, said first sector gear engaging a second sector gear secured to a second of said hinged doors, wherein rotation of said worm gear causes said first and second sector gears to move said pair of hinged doors.

21. The system of claim 16 wherein said air outlet of said duct covers a number of blades of said impeller which is less than one half of the total number of blades of said impeller, with the remainder of said total blades being exposed to allow free removal of air discharged from said air exhaust.

19. A system for prerotating an aircraft'"'"'s landing gear wheel prior to landing, comprising:

at least one landing gear wheel attached to the aircraft by a support;

means for rotating said wheel at selective revolutional speeds while the aircraft is airborn, wherein said wheel has an impeller attached thereto, and wherein said means for rotating said wheel comprises a duct having a forward air intake and an air outlet, said outlet being directed towards said impeller to rotate said wheel, said duct having a variable gate therein to regulate airflow through said duct onto said impeller, said gate being openable by power means responsive to control means for operating said means for rotating said wheel, wherein said airflow through said duct and the rotational speed of said wheel is increased by increased opening of said variable gate to selectively increase and decrease revolutional speeds of said wheel, wherein said variable gate comprises a pair of oppositely disposed hinged doors at said air intake and wherein said power means comprises an electric motor coupled to move gear means, said pair of doors being coupled to said gear means for opening and closing said pair of doors; and

means for measuring the true ground speed comprising a Doppler radar unit in the aircraft to generate ground speed signals, said control means responsive to said ground speed signals.

22. A system for prerotating an aircraft'"'"'s landing gear wheel prior to landing, comprising:

at least one landing gear wheel attached to the aircraft by a support;

non-contact means for rotating said wheel at revolutional speeds while the aircraft is airborn, wherein said means for rotating is in close proximity to said wheel and is not in contact with said wheel to allow said wheel to rotate independently from said means for rotating; and

means for measuring said revolutional speeds of said wheel comprising photoreflector on said wheel and a non-contact photosensor mounted apart from said wheel to generate an r.p.m. signal based on sensing the passing of said photoreflector; and

control means including a microprocessor operable to read r.p.m. signals from said non-contact photosensor and wherein said microprocessor is programmed to send a control signal to said means for rotating said wheel to increase and decrease rotational speed of the wheel responsive to said r.p.m. signal wherein upon an excessively high r.p.m. signal said control signal causes a decrease in rotational speed of the wheel, and inversely upon an excessively low r.p.m. signal said control signal causes an increase in rotational speed of the wheel.

23. A fully automatic closed-loop control system for prerotating the landing gear wheels of an aircraft during approach and landing, retrofitable upon existing and operational aircraft, comprising:

means for causing wheel assembly rotation, wherein wheel rotation is induced solely by force of high velocity air resistance experienced by the aircraft moving fast through the air, such high velocity air being controllably ducted and directed through variable air-intake actuating mechanisms against blades of impellers affixed to each wheel assembly;

means for continuously measuring and transmitting the instantaneous true ground speed of the aircraft throughout approach and landing;

means for independently and continuously sensing and transmitting the instantaneous rotational speed of each landing wheel assembly;

means for independently and continuously controlling the amount of high-velocity air directed against each impeller of each landing wheel assembly, thereby independently increasing, sustaining or decreasing the instantaneous rotational velocity of each wheel assembly to achieve and maintain a peripheral velocity of each tire synchronous with instantaneous ground speed upon wheel touch-down;

means for processing electrical signals from said means for transmitting ground speed and from said means for transmitting rotational speed of each landing wheel assembly, said means for processing and distributing appropriate electrical power of correct polarity and amplitude to all air-intake actuating mechanisms to each operate independently in true closed-loop servo mode.