Compact gyroplane employing torque compensated main rotor and hybrid power train.

Abstract

A compact, compound gyroplane employing torque compensated main rotor and hybrid power train is disclosed. The invention incorporates a torque-compensated main rotor system with a common Collective pitch control but no Cyclic function, which can be driven transiently during flight to allow vertical take-off, landing and hovering flight operations; torque compensation is via a coaxial counter-rotating (CACR) rotor system, or alternatively using one or more electronically-controlled, fixed-pitch, thruster motors. A mechanical or electro-mechanical hybrid power system allows a single engine to power vertical lift and forward propulsion; the use of electric motors for lift and torque compensation facilitates electronic (and potentially autonomous) control of critical phases of flight.

Claims

1. A compact personal aircraft based on a gyroplane, with capabilities for vertical takeoff and landing, and hovering, thereby providing much of the functionality associated with a conventional helicopter, which is safer, simpler to operate, less expensive, and mechanically less complex than existing helicopters. Said gyroplane comprising: an airframe which carries and connects all major components, a fuselage or pod which carries passenger(s) and fuel or power cells and provides attachment points for landing gear, an engine to provide horizontal thrust, a tail assembly for directional stability and control, and a mast to carry a main rotor.

2. to this gyroplane, is added a torque-compensated main rotor system consisting of two or more rotor blades, with a common Collective pitch control to allow modulation of lift, but no Cyclic function, with equivalent function provided by a gimballed rotor head. The torque compensated rotor system can be driven transiently during flight to allow vertical takeoff, landing, and hovering (VTOLH) flight operations.

3. The gyroplane of claim 2 in which torque compensation is via a coaxial counter-rotating (CACR) rotor system.

4. The gyroplane of claim 2 in which torque compensation is achieved using a single rotor in conjunction with one or more electronically-controlled thruster motors.

5. The gyroplane of claim 3 in which a hybrid mechanical, hydraulic or electro-mechanical power system allows use of a single engine or multiple power sources to power vertical lift and forward propulsion.

6. The gyroplane of claim 4 in which a hybrid mechanical, hydraulic or electro-mechanical power system allows use of a single engine or multiple power sources to power vertical lift and forward propulsion.

7. The gyroplane of claim 5 in which the use of electric motors for lift and torque compensation facilitates electronic (and potentially autonomous) control of critical phases of flight.

8. The gyroplane of claim 6 in which the use of electric motors for lift and torque compensation facilitates electronic (and potentially autonomous) control of critical phases of flight.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Drawing 1:

[0037] General Configuration of VTOL Gyroplane.

[0038] The subject invention incorporates key components of a conventional gyroplane including airframe and fuselage, landing gear, an engine and propeller to provide forward thrust, and a main rotor system operating in autorotation, employing a teetering rotor head for directional control. To this platform is added a torque compensated main rotor system and a hybrid power train incorporating hydraulic or electric motors for independent operation and control during vertical phases of flight. This drawing depicts a Coaxial, counter-rotating (CACR) main rotor that can provide torque compensation in the absence of a separate tail rotor or independent thrusters. System components include the following: [0039] 1. Coaxial, Counter-Rotating (CACR) Rotor System (depicted tilted toward viewer for clarity) [0040] 2. Teetering Rotor Head [0041] 3. Electric Drive Motor [0042] 4. Y Tail Control Assembly (see Drawing 2) [0043] 5. Internal Combustion Engine [0044] 6. Propeller [0045] 7. Electric Power System [0046] 8. Landing Gear [0047] 9. Fuselage

[0048] Drawing 2:

[0049] Alternative Tail Configurations of VTOL Gyroplane

[0050] In a conventional gyroplane, the tail functions in a manner analogous to a fixed wing aircraft, providing vertical and horizontal stabilization, and directional control via a rudder. This drawing depicts two alternative realizations of the required functionality while adding additional capabilities employed during vertical flight. Upper left (1-4): a Y tail assembly with downwash deflector tabs, suitable for use with a CACR main rotor. Lower right (5-13) a conventional cruciform tail assembly, incorporating a ducted fan for torque compensation. System components include the following: [0051] 1. Y Tail Control Assembly (used with CACR Rotor System) [0052] 2. Stabilizers [0053] 3. Ruddervators [0054] 4. Rotor Down-wash Deflector Tabs [0055] 5. Cruciform Tail Control Assembly (used with Conventional Rotor System) [0056] 6. Vertical Stabilizer [0057] 7. Rudder [0058] 8. Horizontal Stabilizer [0059] 9. Ducted Fan (for Torque Compensation) [0060] 10. Gyroscopic Sensor [0061] 11. Torque Compensation Controller [0062] 12. Electric Power Supply (Battery) [0063] 13. Electric Power Supply Controller

[0064] Drawing 3:

[0065] CACR Rotor System and Hybrid Power System Detail

[0066] A CACR rotor system is a preferred embodiment of the subject invention, due to the relative simplicity of the mechanism of torque compensation. Although it is possible and potentially useful to drive counter-rotating rotors independently, the use of rotors that are mechanically synchronized allows use of a simpler powertrain and facilitates operation in autorotation.

[0067] System components include the following: [0068] 1. Upper Rotor Assembly of CACR Rotor System [0069] 2. Upper Rotor Head Disk Plate [0070] 3. Upper Rotor Head Drive Shaft [0071] 4. Adjustable Pitch Rotor Spindles (4 or more) [0072] 5. Rotor Blades (4 or more) [0073] 6. Collective Rotor Pitch Adjustment Spool [0074] 7. Collective Rotor Pitch Adjustment Shaft [0075] 8. Lower Rotor Head Disk Plate [0076] 9. Lower Rotor Head Drive Shaft [0077] 10. Collective Rotor Pitch Adjustment Actuator (Electric, Hydraulic, or Mechanical) [0078] 11. Bevel (or Planetary) Gearbox [0079] 12. Universal (or Constant Velocity) Joint [0080] 13. Lower Drive Shaft [0081] 14. 90 Degree Gear Drive [0082] 15. Over-running Clutch [0083] 16. Ring Gear [0084] 17. Power Take-off Drive Shaft [0085] 18. Propeller [0086] 19. Internal Combustion Engine [0087] 20. Electric Motor [0088] 21. Electric Power Controller [0089] 22. Electric Power Supply

DETAILED DESCRIPTION OF THE INVENTION

[0090] We describe a compact personal aircraft with capabilities for vertical takeoff and landing, and hovering, that is safer, simpler, and mechanically less complex than existing helicopters. The invention claimed here solves this problem.

[0091] We propose a compact, compound aircraft based on the general configuration of a gyroplane, with a propeller for propulsion, and a transiently driven, torque-compensated main rotor system which incorporates degrees of freedom to allow the system to self-adjust for aerodynamic forces. Collective adjustment of pitch is employed to allow control of lift, with a teetering main rotor for directional control, instead of the more complex Cyclic control function used by helicopters. Torque compensation is by a coaxial counter-rotating (CACR) rotor system, or alternatively using a conventional rotor paired with one or more electronically controlled thruster motors. The aircraft employs a hybrid power train to enable long range, continuous operation. An internal combustion (IC) engine can be employed to drive the propeller for horizontal propulsion in cruise; during takeoff and landing the main rotor system is driven transiently by the engine via mechanical or hydraulic linkage, or alternatively by one or more electric motor(s). The electric drive system incorporates a battery and power supply system sufficient for full power operation throughout transient phases of flight (vertical take-off, landing and hovering (VTOLH)), recharging the battery during cruise flight using excess power of the IC engine. The use of electric motors facilitates electronic control of function during critical phases of flight. Although some embodiments of this invention would require application of residual power to the main rotor system throughout flight as in conventional helicopters, other designs enable VTOLH gyroplanes with the inherent safety advantages due to cruise operation in autorotation. Derivative designs may produce aircraft with capabilities for relatively seamless transition to high-performance operations on and off-road, on skis, and/or service as an amphibious, fan-driven hydroplane.

[0092] The claimed invention differs from and is an improvement on what currently exists. The invention combines the key functional capabilities of a conventional helicopter for vertical take-off, landing, and hovering, with the advantages of a modern gyroplane, including reduced mechanical complexity, reduced costs of acquisition and maintenance, lower demands on pilot skill and workload, and enhanced safety.

[0093] The mechanical complexity of conventional helicopters contributes to their substantial acquisition and maintenance costs, and introduces multiple potential sources of single point failures. The requirement for proper and coordinated control responses during normal operation, and especially during emergencies contributes to overall operational complexity and required high levels of pilot skill. Conventional gyroplanes are much simpler and less demanding, but are comparatively limited in capability for vertical flight; jump gyroplanes can achieve vertical liftoff but introduce additional mechanical and operational complexity.

[0094] A mechanical or electro-mechanical hybrid power system allows a single engine to power vertical lift and forward propulsion; the use of electric motors for lift and torque compensation facilitates electronic (and potentially autonomous) control of critical phases of flight, and provides a redundant fail-safe power system.

[0095] A Preferred Embodiment of the Invention Discussed Here Includes: [0096] 1. 1: Torque compensating main rotor system [0097] 2. 1a: Coaxial, counter-rotating rotor system [0098] 3. 1b: or, conventional variable pitch rotor with torque compensation [0099] 4. 1c: with common Collective pitch adjustment mechanism [0100] 5. 2: Teetering main rotor head [0101] 6. 3: Power train for transient drive of main rotor system [0102] 7. 3a: via, Mechanical or hydraulic systems coupled to prime mover [0103] 8. 3b: or, One or more electric motors to drive the main rotor [0104] 9. 4: Prime mover, internal combustion engine or turbine. [0105] 10. 5. Propeller for forward flight, driven by prime mover [0106] 11. 6. Generator and charge control system, driven by prime mover [0107] 12. 7. Electric thruster(s) for torque compensation and/or forward thrust [0108] 13. 8. Battery system for transiently driving electric motors

[0109] Relationship Between the Components:

[0110] The torque compensated main rotor system (1) transiently applies power during vertical flight operations (3), while operating in autorotation during cruise. Torque compensation is achieved by the use of a coaxial counter-rotating rotor system (1a) or by use of a simple variable pitch rotor in conjunction with one or more fixed pitch electric thrusters (1b, 7), positioned to compensate for torque (1b). Fan speed is regulated by electronic sensors and feedback systems (7). The main rotor provides Collective control of pitch (1c) for precise regulation of lift, and a teetering head for directional control. Hybrid power systems allow precise and potentially automatic control of critical phases of flight including VTOLH (3). A prime mover driving a propeller meets all power requirements for cruise flight (4,5), while minimizing battery weight (6,8), and providing long range endurance with simple refueling.

[0111] How the Invention Works:

[0112] The operational principles, capabilities, advantages and limitations of the helicopter and of the gyroplane are well understood. The objective of this invention is to combine the principal capabilities and advantages of these two aircraft by employing novel solutions for required functional systems.

[0113] A torque-compensated main rotor system is designed to be transiently powered for liftoff, landing and hovering (as in a helicopter), while allowing the aircraft to operate in autorotation during cruise, in order to achieve the efficiency, and simplicity of operational and emergency procedures associated with gyroplanes.

[0114] In most helicopters, the prime mover (e.g. a piston or turbine engine), directly drives the main rotor in all phases of flight. Torque compensation is by a variable pitch tail rotor mechanically coupled to the main rotor. In a gyroplane the main rotor is not driven in flight, so the aircraft does not require a tail rotor, instead relying on a rudder for yaw control during a rolling takeoff or in cruise flight.

[0115] A Co-Axial, Counter-Rotating (CACR) rotor system provides an alternative solution for a main rotor system, eliminating the need for other systems for torque compensation. It has previously been used in helicopters and has been proposed (but not demonstrated) for use in gyroplanes. Although the advantages of the CACR design are significant, the mechanical design required to implement a helicopter-like Cyclic control function is complex. By eliminating cyclic control in favor of a teetering rotor head design, it is possible to achieve a simpler system suitable for a light helicopter or gyroplane.

[0116] An alternative is to use a conventional variable pitch main rotor, coupled with one or more electrically-driven, fixed-pitch fans. A manual or semi-autonomous controller varies fan speed to modulate torque compensation when the rotor is powered.

[0117] Either of these designs provides a solution for torque compensation necessary for powered vertical flight. In the proposed design, Collective pitch adjustment of the main rotor (as in a helicopter) allows fine control of lift for vertical flight without requiring major excursions in engine speed.

[0118] A teetering rotor head provides directional thrust, analogous to the Cyclic function of a helicopter, but is simpler and much easier to adapt for a CACR rotor system.

[0119] The use of a hybrid power system is useful to optimize the overall performance of the power system given the variation of requirements across a typical flight profile. Application of power to the main rotor system is required for a small fraction of a typical mission: take off, landing and hovering; but requires a substantial fraction of available power. This can be achieved by mechanical or hydraulic pre-rotation systems but is a natural role for transient electrical power. Such a system also provides a back-up power system for controlled descent in the event of a failure of the prime mover.

[0120] The core claims of this patent are 1) to provide a main rotor system that on its own, or in concert with affiliated subsystems, compensates for torque to allow powered vertical flight, and 2) a hybrid power system that allows the rotor system to be transiently driven to power vertical takeoff, landing and hovering.

[0121] How to Make the Invention:

[0122] The invention shares a number of components and subsystems with a helicopter, but is most closely related to a gyroplane.

[0123] The invention incorporates an airframe which carries and connects all major components, a fuselage or pod which carries passenger(s) and fuel and provides attachment points for landing gear, an engine to provide horizontal thrust, a tail assembly for directional stability and control, and a mast to carry a main rotor. Most modern gyroplanes also incorporate a pre-rotation system, allowing the rotor to be driven (while on the ground) to a significant fraction of the rotational speed required for liftoff. Because there is no mechanism to compensate for torque associated with the driven rotor, the pre-rotation system must be disengaged before flight.

[0124] In order to achieve the objectives of the invention, it is necessary to provide a rotor design or system to compensate for torque, to allow the rotor to be powered during vertical flight or hovering, and a power system to allow the main rotor to be transiently powered during vertical phases of flight. In addition, a system for Collective control of pitch is useful for practical designs.

[0125] Replacing a conventional gyroplane rotor (typically 2 blades of fixed pitch) with a variable pitch, co-axial, counter-rotating (CACR) rotor system (consisting of 4 or more blades) is a simple strategy to achieve the objectives of this invention, requiring no other significant alterations to the aircraft. A CACR rotor system satisfying these requirements is described herein.

[0126] Alternatively, it is possible to employ a conventional gyroplane rotor, modified for collective control of pitch, and adding an electrically powered torque compensating tail fan or muiltiple peripheral thrusters to achieve the objectives of this invention.

[0127] In addition, a system for transiently applying power to the main rotor system during vertical phases of flight is required. This might be a high-performance pre-rotation system driven mechanically or hydraulically by the prime mover, or an independent, electrically powered system.

[0128] Essential elements include: 1) the variable-pitch, torque-compensating rotor system, and 2) the hybrid drive system to allow the rotor system to be powered during vertical phases of flight.

[0129] Multiple implementations of each of these essential functional systems are possible and require different subsystems. For example, a CACR main rotor may employ a system of beveled or planetary gears to produce correlated revolution of the counter-rotating blades and to allow the system to be driven from a single source. A single rotor system does not require such a gear system, but does require a sensor-controlled fan for torque compensation.

[0130] Other components or subsystems can be used to enhance the performance of the invention, including a centrifugal clutch and/or variable pitch propeller for the primary propulsion system, an over-running (e.g. sprag) clutch for the main rotor, electronic control and stabilization systems for liftoff and landing or automated flight, and systems to allow regeneration of batteries during cruise flight.

[0131] Other systems such as folding rotors, hydraulically controlled landing gear, winglets, alternative fuselage designs, or systems to apply power to drive one or more wheels, may have utility for specific applications, for example enabling a vehicle capable of land or amphibious operations.

[0132] The invention is described in terms of functional components or subsystems and similar functions may be achieved with various geometrical configurations, power systems, and auxiliary systems.

[0133] How to Use the Invention:

[0134] In order to achieve vertical takeoff in the subject invention typical steps include the following:

1) Verify collective position is full down (low or negative main rotor pitch) to reduce power requirements and prevent unintended liftoff.
2) Start prime mover engine and ensure that horizontal drive propeller is disengaged or in low thrust pitch setting.
3) Apply power to main rotor system and spin-up to the RPM range required for flight.
4) Insure that supplemental torque compensation subsystem is operational (if required)
5) Transition main rotor collective pitch to achieve liftoff, while maintaining desired rotor RPM.
6) Hover as desired within constraints of main rotor power.
7) Transition to forward flight by increasing speed and/or pitch of prime mover propeller.
8) Transition to autorotation by adjusting rotor pitch to normal flight position and disk tilt as required
9) Remove power to main rotor system.
10) Disengage torque compensation system if utilized.

[0135] A similar sequence of steps in reverse order is required for vertical descent and landing:

1) Engage torque compensation system if utilized.
2) Apply power to main rotor system.
3) Adjust disk tilt and reduce forward thrust to achieve desired rate of descent.
4) Increase main rotor power and/or rotor blade pitch to arrest descent and achieve hover.
5) Hover as desired within constraints of main rotor power.
6) Transition main rotor collective pitch to achieve desired descent to landing, while maintaining desired rotor RPM.
7) Verify collective position is full down (low or negative main rotor pitch) to prevent unintended liftoff.
8) Remove main rotor power.
9) Turn off prime mover power.
10) Disengage supplemental torque compensation subsystem (if used).

[0136] Note that many of the steps associated with vertical flight can be automated, especially if power requirements are satisfied by electrical systems.

[0137] Also note that an emergency descent from cruise flight does not require immediate operator intervention, since a gyroplane normally operates in autorotation. The availability of alternative power systems for landing in the event of a prime-mover failure enhances safety and enables automatic procedures.