GB2582133A - Tail sitter helicraft - Google Patents

Abstract

A VTOL aircraft comprises a detachable cabin body 1 with a forward cockpit section and a rearward tail section 6. Fixed wigs are joined to the main body 2a, 2b, and two counter rotating electric prop-rotors 3a, 3b are mounted on one axis along the longitudinal axis and forward of the centre of gravity of the aircraft. These rotors are main rotors at all flight conditions, VTOL, hover and cruise, with capability to be tilted along its mounting axis both backward and forward. A power generator (not shown) simultaneously powers the prop-rotors and charges the batteries. The detachable and rotatable cabin provides sitting in upright position for passengers at all flight conditions. It also can be used as the cabin for a road vehicle. The aircraft may be remotely controlled.

Description

Patent for the Snitch Tail-sitter concept VTOL tail-sitter Air Taxi The present invention relates to a vertical take-off and landing VTOL aircraft and electric car, e.g. an aeroplane capable of vertical take-off and landing and also capable of horizontal flight and also road self-driving capability as a car.

BACKGROUND

VTOL aircraft offer the prospect of eliminating the need for a runway that is otherwise required by those aircraft only capable of achieving high speed horizontal flight. Due to the restriction of requiring a runway, helicopters are often chosen for short range flights as they can be landed on a relatively small, flat surface; such as the roof of a building. However, due to the aerodynamic limitations of the lift generated by a helicopter rotor, they cannot travel as quickly as a fixed wing aircraft and also they don't have wing.

The increasing congestion in the cities and urban areas is the main cause of time wastage for road travellers. VTOL aircraft (Air Taxi) can potentially offer the advantages of aircraft with the ease of vertical take-off and landing of a helicopter.

It is particularly noteworthy that the technology in the aviation and automotive industry has matured without any major innovation for many decades. Although many efforts have been made for enhancing the comfort in the cabin and increasing range and other specifications and even move to electric cars or electric plane, these vehicles still need airports/runways, for the case of aircraft, to takeoff and land and in the case of cars, are limited to the roads and traffic, requiring the time-consuming practice of airport security plus the taxes and expenses of airports.

Some premium travellers and organisations have taken the route of using helicopters because of their flexibility at take-off and landing, but helicopters fall short on measures of emission, speed and comfort.

Furthermore, the high cost of these vehicles has limited their market to large corporations, and very wealthy individuals. In addition, no major environmental achievements have been demonstrated in this industry.

By way of background, VTOL aircraft are well known and now particularly popular, e.g.in the form of radio-controlled drones. An example of a vertical takeoff and landing aircraft is disclosed in US2007/0246601 Al. In this document the vehicle incorporates multiple vertical facing ducted fans for vertical motion and means for achieving conventional horizontal flight.

Another example of VTOL aircraft is provided by US10040547 B wherein an unmanned aircraft is provided with front and rear vertical and horizontal air discharge pathways to facilitate vertical lift and horizontal flight.

In other word, helicopters are good for their VTOL capability but they fall short of speed, comfort and range. Also conventional aircraft are good for their speed, ranges and comfort but they fall short of VTOL capability and they need runways.

A tail-sitter aircraft is proposed to resolve the above primary problem. The concept of a tail-sitting aircraft was included in a patent by Nikola Tesla in 1928 Nikola Tesla U.S. Patent 1,655,114 -Apparatus for Aerial Transportation].

The Focke-Wulf Triebtliigel (wing-driven) fighter was a German tail-sitter project during the Second World War. Three wings were mounted radially as a rotor on a rotating section of the fuselage and driven by small jet engines on the wingtips. The aircraft was to be propelled by this wing rotation. For take-off and landing it would fly vertically as a helicopter, then tilt over horizontally to fly as a self-propelled wing generating both lift and thrust. The contemporary Heinkel Lerche project had an annular wing forming a duct around a conventional propeller, and in the transition from vertical to forward flight the lift would have transferred to the wing. The SNECMA Coleoptere was a postwar French development of the annular wing concept, but powered by a turbojet. It flew in both vertical and horizontal flight modes but never achieved the transition between the two. Meanwhile, the USA was experimenting with propeller-driven design configurations with relatively conventional fixed wings. The Convair XFY Pogo had a delta wing with cruciform tail and successfully demonstrated the full transition between flight modes, while the Lockheed XFV Salmon had a straight wing with X tail but never achieved the flight transition.

A later jet-powered design, the Ryan X-13 Vertijet, first flew in 1955. Two prototypes were made, both flew, made successful transitions to and from horizontal flight, and landed. The final test flight was near Washington DC in 1957. An inherent problem with all these tail-sitter designs was poor pilot visibility, especially of the ground, during vertical descent and landing. This led to the concept being abandoned once a more practical form of VTOL appeared, in the form of thrust vectoring.

SUMMARY OF THE INVENTION

A need has been identified for a small electric cargo or passenger aircraft, that incorporates both VTOL features and comfort, speed and range of conventional aircraft. The prior art comprises VTOL aircraft, e.g. with two counter rotating prop-rotors, providing vertical lift; which allows for a fail-safe operation where auto rotation becomes possible if motors fail. The prior art also features aircraft with two fans embedded in the wings, in order to provide reaction control and balance for moments of prop-rotors at take-off, hover and landing condition allowing full authority. The present invention seeks to address the need for economy of design and greater consideration of occupant safety.

According to a first aspect of the present invention, an aircraft is provided according to claim 1. Particularly, the aircraft includes a main variable angle and detachable cabin having fixed wings extending from a main detachable structure. One of the key advantages of having a set of large counter rotating prop-rotors is the low disk loading that significantly reduces the noise compared to small propellers that often used in other VTOL aircraft at take-off, hover and landing. The low disk loading leads to lower power consumption which is a significant factor for the electric vehicles. An advantage of a winged configuration is high aerodynamic quality and, consequently, less energy consumption for forward flight, this is the feature that helicopter don't have. This prior art is combination of a helicopter at VTOL/ hover mode and an extremely efficient aircraft at forward flight.

The main body further has a detachable cockpit/cabin section and a tail section. The cabin can rotate via different mechanism, i e hinged from the back or in a gimbal design, to give passengers and payload a normal sitting with good horizontal line of sight.

The counter rotating prop-rotors are the selected propulsion for VTOL, transition and cruise modes. However, other means of propulsion that provides similar performance in similar disk area can also so be used. For example a multiple prop-rotors on a disk similar to that of Volocopter 2X (https://www. )copt er.comlen/producti) or a simple quadcopter set can also be used. For the sake of simplicity a counter rotating prop-rotors has been proposed. The main two prop-rotors on top of the aircraft structure is linked to motors with a central rotation mechanism that allows the rotor disk to he at a balancing angle from the structure in order to provide a stable and controllable VTOL and hover mode.

The prior art also comprises a canard behind the main two counter rotating prop-rotors to allow centre of gravity of the aircraft to be in front of the wing at forward flight. The cabin has a hinge that connects it to the fixed wing structure, whilst allowing rotation to the cabin for transition mode from VTOL to forward flight.

The cabin can be of different designs to fit the mission of the vehicle. But it is detachable and it can be attached to a platform of a car without cabin. The key feature here is that a passenger will be able to start his/her journey by using the detachable cabin in the car mode, go to the nearest verti-port, the cabin is detached from the car and gets attached to the tail-sitting VTOL aircraft. Then the aircraft takes off like a helicopter with two counter rotating prop-rotors. As the aircraft has fixed wing and there are always moving air, from prop-rotors flowing over the surfaces of the wings, the aircraft primary control surfaces like, flaps, ailerons and rudder provide necessary lift and control to allow the aircraft to go through transition.

Both prop-rotors are along the centre line of the aircraft. The unique feature of this aircraft is its tilting cabin that allows passengers to always sit comfortable with a clear horizontal line of sight. When the cabin is designed with a spherical or oval shape, along the wing span, its tilting mechanism comes from the gimbal effect along the lateral axis of the wing. But if the cabin is designed to be more aerodynamic it has to move forward along the longitudinal axis and therefore aircraft would need to have canard to compensate the forward centre of gravity. Advantageously, the present invention effectively provides a fail safe operation in the case of loss of power via auto rotation of the prop-rotors similar to that of helicopters. The detachable cabin also allows parachuting of the cabin in the extreme case of loss of rotors and wing.

In some embodiments hybrid propulsion system can be used to increase the range of the aircraft. Hybrid systems are advantageous in that they produce less harmful emissions than gas engines while providing higher power and speed than electric engines thereby providing greater range than an aircraft that is only electric powered. As noted herein, the exemplary form of the VTOL prop-rotors are electrically powered, but alternative/equivalent energy systems may be possible, either known in the art or to be developed in the future.

In some embodiments the aircraft comprises a turbo-generator and a battery or set of batteries, wherein the turbo-generator is configured to charge the electric batteries while simultaneously providing power to the prop-rotors during flight. The skin of the aircraft may be further modified with a solar cell or comparative energy capture device.

In some embodiments the aircraft includes a control system which, among other functions, is capable of automatically varying the thrust created by each electric prop-rotors. Selective/automatic variation of thrust combined with the aircraft primary control surfaces provides the advantage of levelling the aircraft during vertical motion, especially in the case of a wind updraft or other weather phenomena.

The aircraft body and wings are made from a rigid, lightweight structure.

In some embodiments the aircraft interior cabin is designed for the purpose of comfortable human transportation. Particularly, the interior design of the aircraft cabin determines its potential use.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following description presents embodiments of the present invention and, together with the drawings, serves to explain principles of the present invention. However, the scope of the invention is not intended to be limited to the precise details of the embodiments, with variations apparent to a skilled person deemed also to be covered by the description of this invention. Terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features. Descriptive terms should also be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner Directional terms such as "vertical", "horizontal", "up", "down", "upper" and "lower" are used for convenience of explanation usually with reference to the illustrations and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and/or direction.

The present description refers to embodiments with particular combinations of features, however, it is envisaged that further combinations and cross-combinations of compatible features between embodiments will be possible. Indeed, isolated features may function independently from other features and not necessarily be implemented as a complete combination.

The aircraft shown in Figures I to 5 is one embodiment of the present invention. This aircraft comprises a body I with a centre line C and wings 2a and 2b extending outwardly therefrom. At the rear of the body I is a tail section 6. It will be apparent that the wings 2a and 2b, together with the body I, are of a tail-sitter aircraft design as is known in the art.

In front of the body 1 are two variable angle electric counter rotating prop-rotors 3a and 3b are designed to provide the lift at VTOL and hover mode, transition to thrust mode where the lift element is transferred to the wings 2a and 2b and canards 4a and 4b.

At a position to the front of the wings 2a and 2b, adjacent the body lat the tail end, are two rotatable electric prop-rotors 3a and 3b. The rotatable electric prop-rotors 3a and 3b are mounted on a lateral pivot axle to be rotatable through at least 15° and up to 45°.

A particular aspect of the invention is that the aircraft is a "convertiplane" which means that it converts from one mode of flight to another. Helicopters, quadcopters and conventional aircraft all rely on just one form of lift/propulsion, whereas a convertiplane has two: lift force(s)overcome the aircraft weight and this comes from powered prop-rotors in the hover and aerodynamic lift off the wing in "conventional" flight. This means that the aircraft has to "convert" from one mode to the other as it transitions from hover to conventional flight and back again.

Two prop-rotors provide the hover lift capability when air is moving vertically downward on the wings. The wing becomes progressively more effective as forward speed is gained via tilting of the prop-rotors accelerating the aircraft to a point where wing lift is sufficient to carry the weight of the aircraft and payload. It is noteworthy that the transition happens both by prop-rotors tilting and lift created by wings perpendicular to the surface of the wings. The process is reversed for landing.

The aircraft preferably includes a control system that can assist and/or automate some or all inflight functions. For example, the thrust of each of the electric prop-rotors may be selectively varied. A computer that is operable, e.g.by a pilot, may be located within the aircraft body to provide a method of selectively varying the thrust of each of the electric prop-rotors. Control over the thrust of the individual prop-rotors reaction control fans and primary wing and tail control surfaces provides greater stability to the aircraft by enabling control over yaw, pitch and roll.

When sufficient vertical motion has been achieved, i.e. following take-off, the two rotatable electric prop-rotors 3a, 3b tilt about their respective mounting axes to a horizontal thrust position and the wing flaps will be turn down on the wing in order to create lift and help to put the aircraft to the forward motion. Canard also can help adjust the pitch angle, making transitions faster and more efficient. The body I and wings 2a and 2b should be made from any sufficiently rigid and lightweight materials and construction techniques. Furthermore, a suitable landing gear can be incorporated according to requirements, e.g. wheels or skids. Access to the cabin can be provided by conventional car-style doors.

As noted above, the two motors at the rear of the aircraft have thrust vectoring downward during the VTOL operation and then the thrust vectors re-orient to a horizontal positon to push the thrust backward allowing the aircraft to move forward.

According to the state of the art, long haul electric air travel is not presently possible. This problem is addressed in the present context by use of a hybrid system in a form of a power generator positioned at the tail of the aircraft. However, for the city travel, this tail-sitting vertiplane can provide full electric range of 100 miles using state-of-the-art batteries.

Claims (9)

1. Claims: 1. An aircraft comprising: a detachable cabin body, with a forward cockpit section and a rearward tail section, and fixed wings adjoined to the main body; two variable angle and tilting prop-rotors. The main airframe can sit on the tail upward with a rotatable cabin on the lateral axis along the wing.
2. 2. The aircraft according to claim 1, wherein a rotatable and detachable cabin provide sitting upright position for the passengers with horizontal line of sight at all of the flight conditions including VTOL, transition and forward flight.
3. 3. The aircraft according to claim 2, wherein the cabin is rotated either via a gimbal technique or hinged from the end of the cabin whilst it is detachable from the aircraft and can be utilised as the cabin of a road vehicle.
4. 4. The aircraft according to claim 2 or 3, including an electric battery or set of batteries wherein a power generator configured to charge the electric battery while simultaneously electrically powering the prop-rotors.
5. 5. The aircraft according to any of the preceding claims, including an autonomous or remotely piloted controller for automatically varying the lift/thrust created by each rotor, control surfaces and fan.
6. 6. The aircraft according to claim 5, wherein the controller adjusts power to the prop-rotors in a transition mode when, in use, the aircraft is moving forward.
7. 7. The aircraft according to any of the preceding claims, wherein a detachable cabin can be attached to a road vehicle to continue it autonomously journey.
8. 8. The aircraft according to any preceding claim, wherein the body and wings are made from a rigid, lightweight material and/or construction.
9. 9. The aircraft according to any preceding claim, wherein the prop-rotors can be rotated along their mounting axis to tilt in hover for control and stability and tilt forward for the transition mode.