FIELD OF THE INVENTION

[0001] The invention relates to an aerial vehicle. In particular, the invention relates to, but is not limited to, an aerial vehicle configured to allow for lift to be supplied by rotors in one configuration or by wings/aerofoils in a second configuration, and the use of such vehicles in fighting forest fires and/or in search and rescue.

BACKGROUND TO THE INVENTION

[0002] Reference to background art herein is not to be construed as an adm ission that such art constitutes common general knowledge in Australia or elsewhere.

[0003] Aerial vehicles typically fall into four broad categories based on their method of achieving lift:

• Aerostats such as balloons, dirigibles, and blimps;

• Rotorcraft such as helicopters, autogyros and gyrodynes;

• Fixed wing craft such as aeroplanes; and

• Rockets.

[0004] In the field of firefighting, for example, both fixed wing craft and rotor craft are utilised, typically by lifting or pumping water into a hold and releasing the water above the fire to extinguish the fire. Flowever, fixed wing craft lack the fine and precise mobility of rotorcraft, and the ability to hover. Thus, any firefighting by fixed wing craft is generally less targeted than when achieved by a rotorcraft. Conversely, rotorcraft lack the top speed and efficiency of fixed wing craft. Thus, the response times to reach a fire are larger for rotorcraft, and typically use more resources, such as fuel, in use, e.g. to carry water.

[0005] There have been attempts previously to provide a vehicle with some of the advantageous features of both a rotorcraft and a fixed wing craft, often described as convertiplanes such as tiltrotor, tiltwing or stopped rotor craft. However, these craft typically have design trade-offs which means they are unsuitable for fighting fires.

[0006] There is therefore a need for an improved aerial vehicle design.

OBJECT OF THE INVENTION

[0007] It is a preferred object of this invention to provide an aerial vehicle which overcomes or ameliorates one or more of the disadvantages or problems with existing aerial vehicles.

[0008] Other preferred objects of the present invention will become apparent from the following description.

SUMMARY OF INVENTION

[0009] In one form, although not the only form, the invention resides in an aerial vehicle, comprising: an airframe; a drive shaft defining a longitudinal axis of the aerial vehicle; a rotor connected to the drive shaft and comprising blades arranged to rotate about the longitudinal axis, the blades being connected by mechanical linkages that allow the angle of pitch of each of the blades to be varied; a power transmission connected to airframe and drive shaft; a jet turbine connected to the airframe; a wing connected to the air frame defining a wing surface substantially parallel to the longitudinal axis, the wing comprising one or more of control surfaces and flaps configured to direct airflow across the wing surface; wherein the aerial vehicle is convertible between a vertical flight configuration and a horizontal flight configuration, wherein in the vertical flight configuration the rotor provide lift by rotating the blades relative to the airframe, and wherein in the horizontal flight configuration, the rotor is substantially stationary relative to the airframe, and the wing and blades of the rotor both generate vertical lift and both control pitch, yaw, and/or roll of the aerial vehicle as the jet turbine provides horizontal thrust.

[0010] Preferably, the jet turbine is configured to expel a high volume of low oxygen exhaust thrust for extinguishing fires when in the vertical flight configuration.

[0011] In one embodiment, the jet turbine is connected to the drive shaft to provide power to rotate the rotor about the longitudinal axis.

[0012] Suitably, a drive shaft may be provided. The drive shaft may connect the jet turbine to the rotor. A planetary reduction gearbox may be operationally connected to the drive shaft. A clutch for when the rotors are substantially stationary may be provided. The planetary reduction gearbox may be located between the jet turbine and the rotor drive shaft.

[0013] In another form, an electric motor is connected to the drive shaft to provide power to rotate the rotor about the longitudinal axis.

[0014] In another form, a hybrid motor is connected to the drive shaft to provide power to rotate the rotor about the longitudinal axis.

[0015] Preferably, the aerial vehicle further comprises a fuel cell configured to provide fuel to the jet turbine. The fuel cell may be refillable. The fuel cell may be rechargeable. The fuel cell may be replaceable. [0016] Preferably, the fuel cell is modular and configured to be installed or removed in its entirety, allowing for the fuel cell to be replaced in the field. [0017] Preferably, the wing comprises at least one flap for controlling flow of fluid across the wing.

[0018] Preferably, the aerial vehicle comprises control surfaces for navigation or navigation systems such as autopilot.

[0019] Preferably, the aerial vehicle comprises a battery for providing electrical power to the navigation lights and/or the electric motor.

[0020] Preferably, the aerial vehicle comprises a battery recharge system with power generated by the jet turbine to provide electrical power.

[0021 ] Preferably the battery recharge system provides power to run the electric motor.

[0022] Preferably, the aerial vehicle further comprises landing gear for landing on solid surfaces such as runways.

[0023] Preferably the aerial vehicle has landing gear configured to allow the aerial vehicle to take off and land in the vertical flight configuration.

[0024] In another form, the aerial vehicle has landing gear configured to allow the aerial vehicle to take off and land in the horizontal flight configuration.

[0025] Preferably, the landing gear further comprises floatation for landing on water for water rescue.

[0026] Suitably, the floatation landing gear is inflatable.

[0027] Preferably, the floatation landing gear comprises a detachable portion.

[0028] Preferably, the aerial vehicle has alternating pivoting rotors providing upwards or downwards thrust. [0029] Preferably, the aerial vehicle jet turbine has thrust augmentation adapted to an exhaust nozzle.

[0030] Suitably, the aerial vehicle may be manned or unmanned.

[0031] In another form, the invention may reside in a method of fighting a fire. The method preferably utilises an aerial vehicle as hereinbefore described. The method may comprise the steps of: taking off in a vertical flight configuration from a first location; converting to a horizontal flight configuration; travelling to the fire at a second location; converting back to a vertical flight configuration; fighting the fire using exhaust gases of the jet turbine; converting to a horizontal flight configuration when the fire is extinguished or refuelling is required; returning to the first location; converting to a vertical flight configuration; and landing at the first location.

[0032] Preferably the method further comprises the step of replacing a fuel cell of the aerial vehicle at the first location before and/or after flight.

[0033] Further features and advantages of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] By way of example only, preferred embodiments of the invention will be described more fully hereinafter with reference to the accompanying figures, wherein: [0035] Figure 1 illustrates a front view of the aerial vehicle, according to an embodiment of the invention;

[0036] Figure 2 illustrates a front view of the aerial vehicle, according to another embodiment of the invention;

[0037] Figure 3 illustrates a front view of the aerial vehicle, according to another embodiment of the invention;

[0038] Figure 4 illustrates a front view, according to the embodiment shown in Figure 1 ;

[0039] Figure 5 illustrates a front view of the aerial vehicle, according to a further embodiment of the invention;

[0040] Figure 6 illustrates a front view of the aerial vehicle, with wing and flotation attached, according to the embodiment shown in Figure 5;

[0041 ] Figures 7-10 illustrate side views of the aerial vehicle with several different blade configurations;

[0042] Figure 11 illustrates a side view of an aerial vehicle in the horizontal flight configuration.

[0043] Figure 12 illustrates a bottom view of the aerial vehicle, in a horizontal flight configuration;

[0044] Figure 13 illustrates a top view of the aerial vehicle, in a vertical flight configuration;

[0045] Figure 14 illustrates a flight sequence between a vertical and horizontal flight configuration.

DETAILED DESCRIPTION OF THE DRAWINGS

[0046] In this specification, adjectives such as first and second, forward and backward, upward and downward, upper and lower, top and bottom and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or steps, but rather could be one or more of that integer, component, or step etc.

[0047] In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely but may well include other elements not listed.

[0048] With reference to the embodiment shown in Figures 1 and 4, the aerial vehicle is shown in the vertical flight configuration, wherein blades 1 form a rotor which is configured to be rotated via a drive shaft 4. The blades 1 extend substantially perpendicularly from the drive shaft 4. In a preferred form, the blades 1 extend radially from the drive shaft 4. The blades 1 are connected by mechanical linkages 2 that allow the angle of pitch of each of the blades to be varied (as illustrated in figures 7 to 10).

[0049] The drive shaft may be provided power by an electric motor 6. The drive shaft 4 defines a general longitudinal axis of the vehicle, extending through the centre of the vehicle along the drive shaft 4 from a bottom to a top of Figure 4. The electric motor 6 is provided electrical energy from batteries 8, or from a generator within or operatively connected to the jet turbine 12.

[0050] In the vertical flight configuration, lift is provided to the aerial vehicle via the jet turbine and/or rotation of the rotor blades 1 , and the interaction between the air and the profile and angle of the blades 1 . The blades 1 also provide gyroscopic stability for the aerial vehicle in the vertical flight configuration. The vertical flight configuration allows for vertical take off and landing, and hovering. Reaction force to resist rotation of the aerial vehicle can be provided by the control surfaces 5, flaps 14, or via vanes in the jet turbine 12 and/or vanes inside a thrust vector nozzle attached to the exhaust.

[0051] In the horizontal flight configuration, thrust is provided by the jet turbine 12, and lift is provided by the wing 7 and the blades 1 . The angle of pitch of each of the blades 1 can be varied via mechanical linkages 2. This can allow the blades to be oriented with their leading edge substantially in the direction of flight in the horizontal flight configuration.

[0052] In changing from the vertical flight configuration to the horizontal flight configuration, the rotor stops rotating and each blade 1 is oriented with its leading edge in the direction of flight. Thus in the horizontal flight configuration the blades 1 act as wings to provide lift, to reduce in drag on the vehicle, and to provide some fine control such as pitch, yaw, and/or roll of the aerial vehicle.

[0053] The landing gear 11 is formed of four legs, which may be telescopically retractable to reduce drag, and which are configured to contact the ground on take-off and landing in the vertical flight configuration. However, it is envisioned that alternative landing gear could be provided with more or fewer legs or landing gear that is configured to contact the ground in the horizontal flight position. The landing gear may also comprise wheels to allow for taxiing or runway take-off and landing. The landing gear may also comprise flotation attached for on water landing and rescue.

[0054] The fuel cells 9 carry a suitable fuel for powering the jet turbine 12 such as hydrocarbons including aviation turbine fuel, kerosene, octane, iso paraffins biofuels, hydrogen and/ora hybrid of these including batteries. Each fuel cell 9 is attached to the aerial vehicle such that the cells 9 can be removed and replaced in the field, thus allowing for faster refuelling times as opposed to pumping fuel into fixed onboard tanks.

[0055] The jet turbine 12 provides thrust in both the vertical and horizontal flight configurations and can produce an exhaust of low oxygen. Consequently, the aerial vehicle can hover above at a desired altitude and in front at a distance relative to a fire to extinguish it by both starvation of oxygen, with exhaust Co2 and fuel load by blowing the fire front back onto the already burned fire zone.

[0056] The jet turbine 12 is shown as being fixed in relation to the wing 7 and the drive shaft 4, however, it is envisioned that the jet turbine 12 also can be articulated to provide finer control over the direction of thrust, and the direction of the Co2 exhaust gas expulsion.

[0057] The wing 7 comprises several control surfaces 5 and flaps 13 for directing the flow of fluid (e.g. airflow) across its surface. These control surfaces 5 and flaps 13 provide control of the aerial vehicle while in the air in either flight configurations and assist in the stabilisation of the aerial vehicle.

[0058] The Navigation lights 3 provide the aircrafts with direction orientation, port and starboard, and the image sensors 10 can be standard video, infra-red, lidar or radar. The navigation lights 3 may also provide a source of light for the aerial vehicle when flying in the dark.

[0059] The image sensors 10 can be utilised to operate the aerial vehicle remotely, providing visual information to an operator. Both the navigation lights 3 and the image sensors 10 are powered electrically by the battery 8.

[0060] The embodiment shown in Figure 2 differs from the embodiment shown in Figure 1 as the electric motor 6 is replaced with a planetary reduction gearbox and a further shaft that connects the jet turbine 12 to the gearbox 6. This allows for the jet turbine 12 to provide power to the rotor blades 1 mechanically.

[0061 ] Another preferred embodiment of the invention shown in Figures 5- 10 comprises two counter-rotating rotors each with two blades 1. Counter rotating rotors provide equal and opposite rotational forces to the aerial vehicle and work together to stabilise the aerial vehicle. [0062] As can be seen in Figures 7-10 each blade 1 can be rotated to change its angle of attack, allowing control or pitch, yaw, and/or roll of the vehicle for stabilisation and control of the aerial vehicle in conjunction with the wing 7. Figure 11 illustrates the aerial vehicle in the horizontal flight configuration, with each blade 1 positioned to be parallel to the wing 7.

[0063] Figure 11 illustrates the profile of each of the battery 8 and fuel cell 9 which may have a slim shape to provide minimal aerodynamic drag on the aerial vehicle.

[0064] Figure 12 illustrates a bottom view of the aerial vehicle, in a horizontal flight configuration in according to the embodiment shown in Figure 11.

[0065] Figure 13 illustrates a top view of the aerial vehicle, in a vertical flight configuration according to the embodiment shown in Figure 1 ,4, 5, 7. Figure 14 illustrates a flight sequence from a vertical flight configuration (position 1 ) to a vertical flight configuration (position 4) and back again (position 7). Position 1 illustrates a front view stationary on the ground. Position 2 illustrates a front view ascending in a vertical flight configuration. Position 3 Illustrates a side view with sufficient altitude for the rotors to reduce speed. Position 4 Illustrates a side view in a horizontal flight configuration in which the rotors are substantially stationary, preferably providing pitch, roll, yaw, and lift. Position 5 Illustrates a side view commencing decent with the rotors speeding up in preparation for the vertical flight configuration. Position 6 Illustrates a front view in which the rotors and thrust provide controlled descent. Position 7 Illustrates a side view stationary on the ground again.

[0066] In use the aerial vehicle can be manned or unmanned. Typically, the aerial vehicle would: take off in the vertical flight configuration; convert to the horizontal flight configuration once a sufficient altitude has been reached to allow for greater speed; travel to a destination; convert back to the vertical flight configuration to allow for hovering above a point of interest or to fight a fire using the jet turbine; convert to the horizontal flight configuration to return; convert back to the vertical flight configuration for landing. Then, to redeploy the aerial vehicle, the fuel cells would be removed and replaced in their entirety. This allows for minimum downtime for the aerial vehicle and consequently maximum efficiency for fighting fires.

[0067] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above-described invention.