Patent Description:
Rotorcraft can comprise an array of lift devices, such as rotary fans driven by electric motors, supported in fixed relation to one another on a rigid frame structure. Typically such rotorcraft have the lift devices arranged in the same horizontal plane.

Where the lift devices are rotary fans, some lift devices spin clockwise and others spin anticlockwise.

By varying the rate of spin between the clockwise group and the anti clockwise group, yaw can be controlled.

Further, such rotorcraft can control pitch and roll by varying the air displaced by backward devices relative to forward devices, and varying the air displaced by port devices relative to starboard device.

<CIT> relates to a vertical take-off and landing aircraft including an airframe with a central cockpit and two peripheral arrays of ducted rotors driven by electrical engines, wherein said peripheral sections can be folded up or down for storage purpose.

<CIT> relates to control and stabilization of a flight vehicle from a detected perturbation by tilt and rotation.

<CIT> relates to a vertical take-off and landing aircraft for transporting people or loads, has signal processing unit performing position control such that aircraft is horizontally located in space without pilot's control inputs or remote control.

<CIT> relates to a variable-geometry vertical take-off and landing (VTOL) aircraft system.

According to the present invention there is provided an apparatus as set forth in the appended claims.

Referring to <FIG> there is shown a rotorcraft <NUM>, in top view and side view respectively.

The rotorcraft <NUM> comprises an array <NUM> of eighteen lift devices <NUM> supported at a frame structure <NUM>. Further, rotorcraft <NUM> comprises a generator engine unit <NUM> and a flight control system <NUM>.

Lift devices <NUM> are in the form of an electrically driven fan and as such comprise an electrical motor <NUM> about the spindle of which are mounted equally spaced fan blades <NUM>. A protective shroud <NUM> surrounds the periphery of the blades, beyond the swept volume. Each lift device defines a main thrust axis T. Each lift device <NUM> is operable to output the same maximum thrust (i.e. maximum fan speed) but their thrust can be varied independently of other lift devices.

The generator engine unit <NUM> is a fuel burning engine which is in fluid communication with an onboard fuel tank <NUM>. The generator engine unit <NUM> comprises an exhaust section <NUM> which is arranged to exhaust combustion by products along an axis which is generally perpendicular to the main thrust axis T, and can thereby propel the rotorcraft forwards, or leftwards with respect to the Figures page.

The frame structure <NUM> supports the eighteen lift devices <NUM> such that they are in a <NUM> x <NUM> matrix and in a substantially coplanar condition. Thus the lift devices can create a thrust in a common direction, along their respective T axes.

The frame structure <NUM> defines interstitial structure <NUM> between lift devices. These can be used to house or locate components such as the flight control system <NUM>.

The frame structure <NUM> further comprises a main portion <NUM> that houses the back two rows of lift devices (i.e. a <NUM> x <NUM> matrix). Thus a first group <NUM> of lift devices is defined.

Further, the frame structure <NUM> comprises a tiltable portion <NUM> that houses the front row of lift devices (i.e. a <NUM> x <NUM> matrix). Thus a second group <NUM> of lift devices is defined.

Thus with all lift devices <NUM> in the array <NUM> operating with the same fan velocity, the thrust from the first group will be double that of the second group. In practice the first group may generate <NUM>% to <NUM>% of the thrust of the second group when cruising or when all fans in the array are at their maximum output. There may be variations between the port side and starboard side thrust of the first group to control direction and for trim.

The main portion <NUM> and the tiltable portion <NUM> are pivotally coupled by a hinge <NUM> that, for rotorcraft <NUM>, runs across the lower side of the structure <NUM> from port side to starboard side.

The hinge <NUM> permits the rotation or tilt of the tiltable section <NUM> such that the condition of rotorcraft <NUM> can vary from the condition of <FIG> where all lift devices are substantially coplanar. An onboard actuator <NUM> (see <FIG>) is provided for driving the rotation.

A further condition in which the rotorcraft <NUM> can exist is shown in <FIG>. Here, the onboard tilt actuator <NUM> has driven the tiltable portion <NUM> to rotate about the hinge <NUM> by approximately <NUM> degrees. Thus the second group of lift devices have been tilted in concert.

As such, the tiltable portion <NUM> can generate thrust in a second common direction, where a component of the thrust generated by the second group of lift devices <NUM> will tend to accelerate the rotorcraft in a forward direction, or leftwards as shown on the Figures page.

Accordingly, in operation the rotorcraft <NUM> can vary the amount of tilt of the tiltable portion relative to the main portion and thereby move forward.

As the tiltable portion tilts and a component of the thrust provides increasing forward effect, the overall lift of the rotorcraft will tend to be reduced. As such, the flight control system <NUM> is configured to vary the fan velocity of the array of lift devices to maintain a constant lift force as the tiltable portion rotates.

A second rotorcraft <NUM> is shown in <FIG> that, like rotorcraft <NUM>, has an array of lift devices <NUM> in a <NUM> x <NUM> matrix. In second rotorcraft <NUM>, only a portion of the front row of the array is configured as the tiltable portion <NUM>. Accordingly, the hinge <NUM> runs across a portion of the structure but not all the way across. Further, discontinuities <NUM> are provided to permit the lift devices <NUM> in the tiltable portion <NUM> to move relative the lift devices <NUM> of the main portion <NUM>.

A third rotorcraft <NUM> is shown in <FIG>. Here the tiltable portion comprises a first tiltable portion 424a and a second tiltable portion 424b, each thereby defining a first sub-group and a second sub-group of lift devices. Each is provided with its own hinge (426a and 426b respectively) and onboard actuator (not shown). As such the first and second tiltable portions are tiltable independently of each other.

Further, the first tiltable portion 424a is generally to the port side of the rotorcraft <NUM>, and the second tiltable portion 424b is generally to the starboard side of the rotorcraft. Thus, the yaw of the rotorcraft may be controlled by creating a differential between the amount of tilt between the first 424a and second 424b tiltable sections.

Whilst the rotorcraft <NUM>, <NUM> and <NUM> discussed so far have in common the <NUM> x <NUM> matrix of lift devices <NUM>, other configurations of lift devices are contemplated.

<FIG> shows a fourth rotorcraft <NUM> comprising a circular frame structure <NUM> which supports a single lift device at its centre and eight further lift devices at a peripheral ring <NUM>. The circular frame structure comprises spokes <NUM> connecting the peripheral ring <NUM> to the central lift device. The tiltable portion of the structure houses the front most three lift devices supported at the peripheral ring. A hinge <NUM> pivotally couples portions of the peripheral ring <NUM> and portions of the front most three spokes.

Two generator engine units 530a and 530b are provided at the frame structure <NUM> either side of the rearmost lift device.

An adaptation of the rotorcraft is shown in <FIG> b.

In particular in <FIG>, the rotorcraft, which as shown here is the second embodiment rotorcraft <NUM>, further comprises a pilot housing <NUM> and connecting lines attaching the pilot housing <NUM> to the rotorcraft <NUM>.

The pilot housing <NUM> comprises a back frame <NUM> for securely accommodating the back of a pilot, arm loops <NUM> for securely accommodating the arms of a pilot, and leg loops <NUM> for securely accommodating the legs of a pilot. Further cross-straps between loops may be provided (not shown).

The connecting lines <NUM> comprise a riser <NUM> and a pair of top lines <NUM> for each side of the rotorcraft. A starboard riser <NUM> is connected at its first end to the pilot housing and extends to meet, at its second end, the first end of the starboard top lines <NUM>. The starboard top lines <NUM> then extend to connect, at their second ends, to respective attachment points on the foremost and aft most lift devices on the starboard side of the array. A port riser and port top lines extend in an equivalent manner between the pilot housing and the port most back and frond lift devices of the array.

The connecting lines <NUM> are flexible and generally inextensible and the port and starboard sides are of substantially equal length. As such the pilot housing hangs directly below the centroid axis C of the rotorcraft, when the rotorcraft is horizontal.

The connecting lines <NUM> and steering lines pivotally affix to the frame structure or pilot housing. In particular there may be a lug provided at the frame structure or pilot housing into which a karabiner at the end of the lines <NUM> or <NUM> can interlock.

Further provided are a pair of steering lines <NUM>, one for the port side and one for the starboard side. Each steering line <NUM> attaches at its first end <NUM> to the tiltable portion of the frame structure. The starboard steering line <NUM> attaches to the frame at the foremost starboard lift device. The port steering line <NUM> attaches to the frame at the foremost port lift device. The second end of the steering lines <NUM> connect to a respective handle <NUM> and is configured to be proximate to the pilot housing such that a housed pilot can reach the handles <NUM>. As shown, the steering lines <NUM> are routed via the second end of the risers <NUM> so as to tether the steering lines <NUM> and to tend to provide them at the pilot housing. The routing of the steering lines <NUM> at their respective risers <NUM> is such that the steering line can slide relative to the riser <NUM>.

The steering lines <NUM> are flexible and generally inextensible and as such drawing the handles <NUM> away from the array of lift devices will tend to tilt the tiltable portion of the frame structure. Any onboard tilt actuators are configured to allow this. Further, the hinge may be sprung such that the tiltable portion is biased to assume the planar condition.

In <FIG>, an adaptation has been made to the first rotorcraft <NUM> whereby a pilot housing, housing pilot P, and connecting lines have been added. Here, the connecting lines comprise three top lines on either side and connect to the foremost, middle and aft most lift device in the main portion.

Further, an attachment line <NUM> extends between the pilot housing <NUM> and a payload L.

As an alternative to the steering lines <NUM> shown in <FIG>, which directly actuate the tiltable portion, there may be provided a pilot console <NUM> at the pilot housing <NUM>.

Such a pilot console <NUM> comprises an interface (e.g. buttons and joystick) whereby the pilot can input instructions, and an operable link to the flight control system so that such instructions can be understood and relayed to the onboard tilt actuator <NUM>.

The flight control system <NUM>, suitable for any of the preceding rotorcraft but particularly configured for the <FIG> rotorcraft, comprises a flight control computer <NUM>, a communications module <NUM>, an autopilot <NUM>, and an energy storage unit <NUM>.

The energy storage unit <NUM> has the form of an electrical battery and is operable to supply electrical power (shown as a dashed line) to the flight control computer <NUM>, the autopilot module <NUM>, and the communications module <NUM>. Further, the energy storage unit <NUM> is operable to supply power to components outside of the flight control system <NUM>, namely the array <NUM> of lift devices and the onboard tilt actuator <NUM>, the generator unit <NUM> and fuel tank <NUM>, and the pilot console <NUM>.

The energy storage module <NUM> is also operable to receive electrical power from the generator unit <NUM>, which would tend to be the main operating condition of the system.

The combination of the energy storage unit <NUM> and the generator unit <NUM> can be considered as an electrical power source.

The flight control computer <NUM> is operably connected to other components such that it can receive input data and transmit output data (shown as a solid line) from and to such other components. Such data may be conveyed via wired links or wireless/RF links.

In particular, the flight control computer <NUM> can transmit to the array of lift devices <NUM> instructions on how the array is to configure itself moment to moment, for example what target fan speed each lift device should be set at. Such instructions could be broken down into instructions for each lift devices <NUM> in the array, delivered independently via a bus architecture on the rotorcraft. Data could also be fed back to the computer <NUM> e.g. the actual fan speeds achieved at each lift device <NUM>; hence feedback algorithms at the computer <NUM> could regulate and control the lift devices in a dynamic environment.

Further, the onboard tilt actuator <NUM> can receive instructions from the flight control computer <NUM> which could pertain to the tilt that needed to be effected.

In particular, the flight control computer <NUM> can receive flight control instructions from the pilot console <NUM>, and can transmit status reports (e.g. relating to fuel levels) to the pilot console <NUM>. The pilot console <NUM> is arranged to convert pilot instructions (shown as the dotted line) into the machine-readable data (shown as the solid line), and to convert machine-readable status reports into pilot-readable information.

Further, the pilot console <NUM> shown here is operable to communicate wirelessly with the flight control system <NUM> and as such instructions from the console <NUM> may be relayed to the flight control computer <NUM> via the communications module <NUM>. Such a module <NUM> is operable to convert the machine-readable wireless/RF signal into a machine-readable electrical signal suitable for feeding into the computer <NUM>. The communications module <NUM> is provide with an antenna unit <NUM> for receiving and transmitting wireless RF signals.

The communications module <NUM> is also operable to communicate with a remote operator. The remote operator, once linked to the flight control system <NUM> by the communications module <NUM> is able to send and receive flight data and can thereby remotely pilot or monitor the rotorcraft.

The flight control computer <NUM> can also receive flight control input data from the autopilot <NUM>, and if appropriate can feed back data to the autopilot <NUM>.

Accordingly the rotorcraft can be controlled by the onboard pilot, the remote operator, or the autopilot <NUM>. Further, the rotorcraft can be controlled by any combination of these where appropriate provisions for hierarchy of command are in place.

Also shown in <FIG> is the steering line <NUM>, which illustrates that the array of lift devices <NUM> can be directly actuated (see the dot-dash line).

For rotorcraft without the adaptations shown in <FIG>, the flight control system <NUM> can be simplified in so far as there is no local pilot. Accordingly, the pilot actuation methods of the steering line/direct actuation <NUM> and the pilot console <NUM> will not be present and can be absent. Such rotorcraft would tend to be controlled by the remote operator and/or the autopilot <NUM>.

Referring to <FIG> there is shown a method of using a rotorcraft as shown in <FIG> to deploy a pilot to a destination.

In step S2, the rotorcraft is manoeuvred to the pilot at a departure point location. Such manoeuvring would tend to involve the rotorcraft hovering at a height from the ground such that the pilot housing <NUM> is easily accessible by the pilot.

In step S4, the pilot is coupled into the pilot housing <NUM>. Where the pilot housing <NUM> is of the harness type used by parachutists, the pilot will be familiar with the use and will be able to easily couple themselves to the housing <NUM> and hence the rotorcraft. An optional extra step at this point would be to further couple a payload L (e.g. the pilot's luggage or kit) to the housing <NUM>.

In step S6, the pilot controls the rotorcraft for example by varying the tilt of the tiltable portion <NUM> of the array <NUM> (though the rotorcraft could alternatively be controlled by a remote operator, or the onboard autopilot, or combinations of all three) and flies the rotorcraft to the pilot's destination.

In step S8, with the pilot at the destination, the rotorcraft can hover at a suitable distance from the ground to allow the pilot to safely decouple from the pilot housing <NUM>. Hence the pilot is deployed to their destination. If a payload L has been connected to the pilot housing <NUM>, this can be decoupled here too.

Decoupling may involve removing the connecting lines <NUM> and any steering lines <NUM> and having the pilot look after them. Alternatively, after the pilot has decoupled from the rotorcraft, the frame structure <NUM> may reel in the lines <NUM>, <NUM> and stow them safely in an interstitial space <NUM> for the onward flight.

In step S10 the rotorcraft is controlled and flown to the rotorcraft destination. Such control will tend to be done by the remote operator or the autopilot <NUM>. The rotorcraft destination may be the departure point, or may be a third location.

The rotorcraft described herein provide an additional manoeuvre mechanism for rotorcraft. This can lead to a more energy efficient and/or faster travel in the direction of tilt. Hence the rotorcraft can tend to travel further for a given amount of energy.

Further, rotorcraft with the pilot adaptation can, as compared to other personnel transport devices such as parachutes and microlight aircraft, be provided to hover prior to carrying the personnel. This can be a safer or more convenient process.

Moreover, rotorcraft with the adaptation tend to provide that the pilot is a greater distance away from hazardous components such as the fan blade or generator and so is potentially safer. Further, provided the pilot is wearing an auxiliary parachute, then there is above a certain ceiling a safe mid-flight abandonment procedure whereby the pilot decouples from the housing and deploys their auxiliary parachute - with minimal risk of hitting the array of lift devices.

Still further rotorcraft with the adaptation provide a personnel deployment device which can be retrieved independently of the pilot and so can potentially be reused with a smaller turn around time, or can leave less trace of deployment, or can leave the pilot with a smaller mass to carry.

Various alternatives to and adaptations of components of the rotorcraft are contemplated. For example:.

Claim 1:
A rotorcraft (<NUM>) comprising:
an array (<NUM>) of lift devices (<NUM>) wherein the array of lift devices (<NUM>) comprises a first group (<NUM>) of lift devices (<NUM>); a second group (<NUM>) of lift devices (<NUM>), the second group (<NUM>) being tiltable, in flight, relative to the first group;
a pilot housing (<NUM>) that hangs directly below the centroid axis (C) of the rotorcraft (<NUM>) when the rotorcraft (<NUM>) is horizontal;
connecting lines (<NUM>) attaching the pilot housing (<NUM>) to the array of lift devices (<NUM>); and
an actuator interface at the pilot housing (<NUM>) such that the pilot can steer the rotorcraft (<NUM>).