STOL AIRCRAFT
20200102068 ยท 2020-04-02
Inventors
Cpc classification
B64C2025/008
PERFORMING OPERATIONS; TRANSPORTING
B64C25/001
PERFORMING OPERATIONS; TRANSPORTING
B64C25/405
PERFORMING OPERATIONS; TRANSPORTING
B64C25/26
PERFORMING OPERATIONS; TRANSPORTING
B64D35/02
PERFORMING OPERATIONS; TRANSPORTING
B64D41/00
PERFORMING OPERATIONS; TRANSPORTING
B64C29/00
PERFORMING OPERATIONS; TRANSPORTING
Y02T50/80
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
B64C1/06
PERFORMING OPERATIONS; TRANSPORTING
B64C25/40
PERFORMING OPERATIONS; TRANSPORTING
B64D41/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An electrically powered STOL aircraft having dedicated motors energized to deploy movable landing gear driven to propel short takeoffs and to actively rotate downwardly to engage the runway surface as the aircraft approaches touchdown on landing. The front and rear landing gear, or both, may be powered and actuated in the landing process with braking to shorten the landing distance, each driven landing gear wheel having a dedicated electric motor and coaxial brake. The landing gear modules are configured and controllable to differentially deploy downwardly so as to enable countersteering during taxi maneuvers and turns.
Claims
1. An aircraft comprising: a fuselage having a pivotally attached nosecone/windscreen which pivots to open a passenger and cargo compartment; a pair of opposing fixed wings coupled to opposite sides of said fuselage and extending laterally therefrom; one or more propellers coupled to at least one of said wings or said fuselage to provide axially directed thrust to propel said aircraft forwardly; one or more motors to drive said propellers; at least one power source coupled to said one or more motors to supply energy to said one or more motors; and two fore and one after retractable and deployable landing gear modules coupled to one or more of said fuselage and said wings and operative to rotate during landing to absorb vertical sink energy of said aircraft and to reduce shock to aircraft occupants, said landing gear modules including a proximal and a distal landing gear module; wherein said fore landing gear modules are configured and controllable to differentially deploy downwardly so as to enable countersteering during taxi maneuvers and turns.
2. The aircraft of claim 1, further comprising a landing gear control system operative to lower landing gear on approach to landing such that the reactive vertical force of landing is primarily absorbed by said landing gear.
3. The aircraft of claim 1, wherein at least one landing gear module comprises a linear strut member coupled to said fuselage by a rotary joint at a proximal end with the distal end supporting at least one wheel in rotary engagement.
4. The aircraft of claim 3, wherein said linear strut member is operative to rotate during takeoff to provide rotation and lift of said fuselage.
5. The aircraft of claim 4, wherein said linear strut member has a motor driven wheel to accelerate the aircraft on the ground during takeoff.
6. An STOL aircraft, comprising: a fuselage having a port and a starboard side; at least one fixed wing coupled to said fuselage and extending laterally from each of said port and said starboard side; at least one propeller coupled to either said fuselage or said at least one fixed wing to provide thrust; a power plant to power said at least one propeller; front and rear landing gear modules operatively coupled to said fuselage, each of said front and rear landing gear modules including at least one rotatable landing gear strut with a wheel disposed on its distal end, wherein said front landing gear modules are configured and controllable to differentially deploy downwardly so as to enable countersteering during taxi maneuvers and turns; landing gear motors for driving said front and said rear landing gear struts independently; and a control system for controlling said landing gear motors to deploy and retract said front and rear landing gear struts; wherein said control system is configured to rotate one or more of said landing gear struts in response to aircraft flight condition and position data, including airspeed, groundspeed, and position in relation to a runway.
7. The STOL of claim 6, wherein at least one of said wheels of said front landing gear strut or said rear landing gear strut is motor driven.
8. The STOL of claim 7, wherein each of said wheels of said at least one front landing gear strut or said rear landing gear strut is motor driven.
9. The STOL of claim 6, wherein said front landing gear includes a port landing gear strut and a starboard landing gear strut, each rotatingly coupled to said fuselage.
10. The STOL of claim 9, wherein said front landing gear struts are independently controlled and can be deployed and retracted independently of one another.
11. The STOL of claim 9, wherein said control system is programmed to drive said at least one front landing gear strut downwardly during takeoff to increase the aircraft angle of attack.
12. The STOL of claim 9, wherein said control system is configured to drive said at least one front landing gear strut downwardly during landing to expedite ground contact by said front landing gear strut wheel.
13. The STOL of claim 9, wherein said control system is configured to drive said front and rear landing gear struts downwardly during landing to expedite ground contact by said front and rear landing gear strut wheels.
14. The STOL of claim 9, wherein said control system is configured to drive said front and rear landing gear struts downwardly during landing to expedite ground contact by said front and rear landing gear strut wheels.
15. The STOL of claim 14, wherein said control system is configured to rotate said landing gear after touchdown on landing to absorb the energy.
16. The STOL of claim 6, wherein said at least one power plant is an electric power plant.
17. An electrically powered STOL aircraft, comprising: a fuselage; fixed wings coupled to said fuselage; at least three electrically powered landing gear modules operatively coupled to said fuselage, each of said landing gear modules including a rotatable strut having a wheel disposed on an outer end, wherein said landing gear modules are configured and controllable to differentially deploy downwardly so as to enable countersteering during taxi maneuvers and turns; an electric power supply disposed in said fuselage; at least one propeller mounted on said fuselage or on said wings; at least one power plant electrically coupled to said electric power supply to provide power to said at least one propeller; an avionics control system for selectively deploying said at least three landing gear modules, including deploying said front landing gear downward to induce rotation on takeoff and actively deploying one or more of said landing gear modules downwardly to close the distance to the runway on landing and retract after touchdown to absorb energy.
18. The aircraft of claim 17, wherein at least one of said landing gear struts includes a driven wheel disposed on an outer end.
19. The aircraft of claim 18, wherein at least one wheel of each of said front and rear landing gear modules includes a driven wheel.
20. The aircraft of claim 17, wherein said avionics control system lowers at least one module of said landing gear modules on landing in response to aircraft flight conditions and position in relation to a runway.
Description
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0025] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
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DETAILED DESCRIPTION OF THE INVENTION
[0049] Referring first to
[0050] Preferred embodiments of the aircraft 100 achieve short takeoffs and landings whether piloted or unpiloted, as in remotely controlled drone flight. In the preferred embodiments having the shortest takeoff and landing distance, the avionic systems control critical landing gear movements and the overall landing gear configuration to coordinate gear positions with one or more of the following conditions, including height, airspeed, ground speed, and runway position.
[0051] In accordance with the present invention the STOL aircraft 100 comprises a central fuselage 110 that supports left and right wings 120 and 120. Empennage (tail wing assembly) 190 includes elevators 191. The empennage may be any of a high-wing, low-wing, or mid-wing design.
[0052] Fuselage 110 in preferred embodiments deploys a globular cockpit (passenger and cargo compartment) 115 and can provide or be extended to provide a cargo bay. The fuselage includes an axially disposed aft frame member 111 that supports the tail assembly at the distal end 111b, with the proximal end 111a joined at the common wing junction above the globular cockpit.
[0053] In preferred embodiments the front landing gear 150 is deployed in the landing process to absorb energy, and both the front and rear landing gear configurations and operation enable short takeoff distances.
[0054] The front landing gear 150 preferably comprises a pair of struts 151/151 on opposing right and left sides of the fuselage 110, each with the drive mechanism shown in
[0055] The preferred modes of takeoff and landing are further enabled by the configuration of the fuselage and other heavy components that position the center of gravity (COG) between the front and rear landing gear.
[0056] The two front landing gear struts 151, 151 and the rear landing gear strut 156 are each driven by a separate motor, preferably electric.
[0057] Front landing gear 150 and rear landing gear 155 are connected to the globular cockpit 115. As shown in
[0058] The rear landing gear 155 deploys a linear strut 156 and includes a wheel 162 at a distal end, and a pivotal connection to the fuselage 110 or cockpit 115 using a rotary joint or coupling 157. Wheel 162 is driven by an in-line motor (not shown) to accelerate the aircraft for takeoff. It is preferably operatively coordinated with the movement of the front landing gear 150 by a Ground-Air-Made-Short (GAMS) landing gear 1500.
[0059] Successful short runway landings require that the aircraft wheels touch down in a narrow range in the landing zone. The requirements may be on the order of a tenth of a second for the minimum potential runway length. The means to achieve such exactitude is to have the landing gear reach for the ground at the exact moment needed, which means that the landing gear is actively rotated downwardly in relation to landing conditions data relating to height over the runway, position in the landing zone, ground speed, vertical speed, and so forth. As the aircraft nears the runway, the avionics control system rotates the landing gear down to engage the ground before the gear would otherwise contact the ground on a glide path for decelerating the plane.
[0060] The other part of the solution is to eliminate wing loading and transfer weight onto the landing gear to maintain high deceleration through wheel braking. As speed drops, high deceleration is difficult to achieve aerodynamically. It is a key requirement, therefore, to initiate and produce as much forward horizontal deceleration in the air and maintain that deceleration during landing.
[0061] The GAMS landing gear 1500 employs a motor 1520 to position the front landing gear 150 and rear landing gear 155. The same assembly includes a disc brake 1530 to dissipate the vertical sink energy. The elongate and relatively long landing arms or struts 151/151 and 156 are dimensioned to accommodate a wide variety of approach conditions and to ensure that the aircraft does not bounce or porpoise on touchdown and rollout.
[0062] The front landing gear 150 deploys the wheel supporting struts 151 downwardly when they are in a range of distance from the ground that they will touch the ground as they descend. The contact is sensed so that the wings can then be actively and rapidly unloaded of lift (using, for instance, spoilers), so vertical deceleration is absorbed by the forward landing gear brakes as well as the wheel brakes that absorb horizontal deceleration.
[0063] A long wheelbase (the distance between front wheels 161 and rear wheel 162) when the gear is deployed may be advantageous for acceleration on takeoff, but it is disadvantageous for rotation on takeoff. Wheeled vehicle acceleration and deceleration requires a long wheelbase with the center of gravity near the midline. The need for easy and quick embarkation introduces further challenges. An aircraft with a long wheelbase cannot take off without powered assistance. Thus, the same GAMS power unit is employed to force the aircraft to rotate for takeoff.
[0064] In a preferred embodiment, a plurality of electric motors provide land and flight propulsion.
[0065] In another preferred embodiment, at least one landing gear wheel drives the plane on the ground to the lift off speed. The strut portion of the gear is then driven to provide upward thrust at lift off. The upward thrust from the landing gear adds to the lift provided by wings. The GAMS mechanism of
[0066] The preferred embodiments of the aircraft 100 are expected to have a runway length requirement of 60 meters or less.
[0067] The GAMS power unit 1500 is illustrated in detail in
[0068] On landing, shaft 1540 moves in the reverse direction, counter rotating the motor to absorb the energy of landing as the strut 156 moves upwardly, with the energy also absorbed by the disc brake 1530. Landing energy can also be absorbed by one or more conventional shock absorbers, such as various forms of springs, as well as active suspension systems that may deploy electromagnetic actuators, as well as combinations thereof. Such energy absorbing systems can have any combination of linear and non-linear energy absorption.
[0069] The GAMS power unit also operates to lift and deploy the forward wheels 161/161 by rotating struts 151/151. The forward wheel struts 151/151 each have a lateral shaft 153/153 coupling to rotate as the hinged coupling 1560 is rotated by the ball screw actuator arm 1580 that couples in turn to the ball joint 1550 that receives the threaded shaft 1540 connecting to the motor 1520. Other motors drive the propellers, landing gear, control surfaces, and wheels for ground propulsion, and are powered by a modular battery 140 capable of fast interchange for quick turnaround.
[0070] An energy or power source 140 provides energy to power the motors 135/135. One or more primary motors which drive one or more propellers 130/130, which may be two motors 135 and 135 mounted on the left 120 and right 120 wings. A modular battery 140 is a preferred power source. The modular battery 140 may be mounted to the fuselage 110 or aircraft so that it can be jettisoned rapidly in the event of fire or any other impending hazardous state or condition. The power source 140 can be a sort of solid state battery as well as a fuel cell and a source of hydrogen for the fuel cell. Alternatively, the power source can be liquid fuel that drives an internal combustion motor, which in turn generates electricity by driving an electric dynamo-machine, i.e., a generator.
[0071] It should also be appreciated that it is preferable that the COG is disposed between the front landing gear 150 and rear landing gear 155 by the central placement of the passenger seats and the power supply.
[0072] The battery is preferably supported by translating it longitudinally within the airframe to adjust the COG with respect to the load from passengers or freight. Placement of battery, cargo containment means (and other heavy components) within the fuselage 110 and cockpit 115 properly positions the COG.
[0073] An optional cargo bay is preferably a module that forms part of the outer skin on the fuselage behind the cockpit.
[0074] Looking next at
[0075] Referring now to
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[0077] The front landing gear module includes port and starboard struts or legs 252, 254, respectively. Each leg includes, at a distal end, a fetlock 256, 258, pivotally connected to the leg at a fetlock pivot 260, 262; a front cradle 264, 266 (latter not showing) pivotally coupled to the fetlock at a cradle pivot 268, 270 (latter not shown); a cowling 272, 274 pivotally connected to the front cradle at a cowling pivot 276, 278; and terminating in driven wheels 280, 282, rotatingly disposed on axles 284, 286 (port side not visible). Drive systems/motors 288, 290 are provided for each wheel (again, port side not visible). Clamshell doors 292, 294 may be provided to enclose the wheels in flight.
[0078] Each front landing gear strut 252, 254 (port and starboard) terminates as an inboard rotatable deployment/retraction axle 300, 302, each axle disposed through an airframe socket, port and starboard, 206, 208, respectively. Each axle is driven by a lead screw 304, 306 pivotally connected to the axle with a pintle/gudgeon coupling 308, 310. The coupling and axle form bell cranks 312, 314.
[0079] Electric motors 316, 318 are mounted to the airframe interior side 202 with a trunnion/bracket mount 320, 322, which extend their respective lead screws to retract the corresponding strut or retract their respective lead screws to deploy or extend the respective strut. Motor trunnions pivot at pivot points 324, 326 (latter not clearly visible). Motor control for both the deployment/retraction of the landing gear struts and for their respective drive wheels resides in system avionics described more fully below.
[0080] In the embodiment shown in
[0081] The rear landing gear, like the front landing gear, is driven by a strut drive system, 370, which in embodiments is an electric motor. It is mounted on the airframe inner side with a motor trunnion 372 pivotally mounted on a trunnion bracket 374. The motor drives a lead screw 376 that engages a rear strut clevis 378 to pivot the strut on a rear strut shaft 380 disposed in a trunnion carriage 382. Motor control again resides in avionics control systems, described more fully below.
[0082] Operation of the landing gear modules just described may be seen by referring now to
[0083] Thus, and looking first at
[0084] Looking next at
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[0087] In preferred embodiments, the avionics system controls the landing gear deployment in coordination with the propeller and wheel drives for the precise movement with respect to location and speed to fully enable the STOL advantages. Such an avionics control system may be capable of remote or drone control, as well as autonomous or semi-autonomous control. More pertinently, the landing gear system control may be pilot controlled or, in a pilotless/autonomously controlled embodiment, controlled with on-board system avionics or remotely controlled from a centralized control system.
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[0090] Referring next to
[0091] Loading and unloading is further facilitated by pivoting nosecone/cockpit windshield 115a upwardly so as to open the interior cockpit and cargo areas 115b to passengers. Kneeling also tilts the passenger seat forward, making getting in and out the seat less awkward and more pleasant. Kneeling is accomplished using the versatile GAMS landing gear, in this case by having both front legs 151, 151 smoothly and gently lower the nose of the plane down. Multiple sensors ensure that no obstacles impede the nose down movement before the aircraft kneels. Note that in this configuration, wings 120, 120 are folded up for compactness and parking at the passenger gate or on the flight deck.
[0092] The banking or tilt configuration 750, shown in
[0093] A principal objective of the banking/tilting system is to reduce turnaround time by moving faster, eliminating steps, or lessening the risk of interruptions. To maintain passenger comfort and safety, the system imposes strict limits on jerk forces during takeoff, landing, and maneuvering on the flight deck and decks below the flight deck. Jerk is the change in rate of acceleration. It can be typically experienced on a motorcycle or in a car when peeling out fast or coming to an abrupt stop. The units for jerk are g/sec or m/sec.sup.3. Jerk is a measure of that abruptness.
[0094] One of the ways of limiting side forces while taxiing on the ground is to tilt or bank the plane into the turns (i.e., to countersteer), much as in the manner of a motorcycle. This offsets centrifugal forces, which tend to move passengers laterally in their seats, and thus keeps the passengers comfortably seated with their bodily centers of mass generally pushed down and into the centers of their seats. It also eliminates the feeling of dawdling along to get to the gate.
[0095] Banking is accomplished by forcing the appropriate landing gear arm (in this instance, left/port arm 151) to retract upwardly from its forward ground-engaging position which tilts the plane into the turn (here shown as a left hand turn). Although a simple inclinometer would be the only necessary instrument needed to regulate the proper bank angle, the suite of instruments already on board is more than adequate to determine the needed bank angle as a function of turning radius and forward speed.
[0096] From the foregoing, it will be seen that in its most essential aspects, the present invention is an STOL aircraft that includes a fuselage having a port and a starboard side; at least one fixed wing coupled to the fuselage and extending laterally from each of the port and the starboard side; at least one propeller coupled to either the fuselage or the at least one fixed wing to provide thrust; a power plant to power the at least one propeller; front and rear landing gear modules operatively coupled to the fuselage, each of the front and rear landing gear modules including at least one rotatable landing gear strut with a wheel disposed on its distal end; landing gear motors for driving the front and the rear landing gear struts independently; and a control system for controlling the landing gear motors to deploy and retract the front and rear landing gear struts; wherein the control system is programmed to rotate one or more of the landing gear struts in response to aircraft flight condition and position data, including airspeed, ground speed, and position in relation to a runway.
[0097] Advantages of embodiments of the invention arise from the preferred exclusive use of electric motors for all the drive mechanisms to improve reliability and to decrease maintenance, as this eliminates fuel and hydraulic lines, which are prone to leaks and failure over time. Such leaks can create slip hazards on airstrips and reduce an aircraft's ability to decelerate safely in a limited space.
[0098] The foregoing disclosure is sufficient to enable those with skill in the relevant art to practice the invention without undue experimentation.
[0099] While the particular aircraft herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages stated herein, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims. For instance, those with skill will appreciate that the advantageous feature of the landing gearthat of reaching for the runway surface close to touchdowncould be accomplished with alternative mechanical structures, such as telescoping landing gear struts or struts that articulate at a point along the length of the struts distal to the connections at the fuselage. Accordingly, the proper scope of the present invention should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications as well as all relationships equivalent to those illustrated in the drawings and described in the specification.