There is current interest in the use of uninhabited air vehicles (UAVs) as a rapid response in a time of military conflict. However, although the maintenance requirements are less than for conventional piloted aircraft, there would still be a substantial expense in maintaining these in a state of readiness. One option would be to keep them continually maintained as in an existing airfleet but this would be extremely expensive.

Another possibility would be to mothball or cocoon the UAVs in the conventional manner. However the methods used at present for the storage of air vehicles are relatively unsophisticated. Thus air vehicles are stored in a hangar or similar building without any air conditioning, rather than in a dedicated facility designed for the task. The stored vehicles are inhibited and cocooned for storage and this provides a degree of protection from the environment.

During storage maintenance is not carried out on the air vehicles. The consequences of the cocooning and lack of maintenance means that generation of the air vehicles to operational status takes weeks rather than days. There is therefore a need for a storage facility which mitigates at least some of these disadvantages and which allows a commander to deploy UAVs immediately when the situation demands even though the UAVs may not have been in active

service for several years, whilst not incurring substantial annual maintenance costs.

US Patent No 3,865,009 discloses a missile launcher for, e. g. a ship. The launcher comprises a cluster of separate missile bays which are each completely enclosed and environmentally protected. The document is concerned with self-contained missile bays.

British Patent Nos. 434,958 and 506,737 disclose arrangements for storing a number of aircraft.

US Patent 5,153,367 describes a cocoon system for a missile which incorporates environmental control.

US Patent 5,136,857 describes an airconditioning system for an aeroplane hangar e. g. used as a spray shop.

US Patent No. 5,119,935 describes a metal knock-flat container for a VTOL aircraft which may serve as a weather- tight hangar or as a take off and landing pad. There is no suggestion of providing environmental control of the atmosphere within the container.

French published Application No. 2,391,122A discloses an environmentally controlled container for containing two missiles.

None of the above documents address the problem of maintaining a fleet of air vehicles within a common enclosed space in a building, ready for rapid deployment, without needing to cocoon them and whilst allowing ready access to the vehicles for maintenance etc.

Accordingly, in one aspect, this invention provides a method of providing a rapidly deployable plurality of air vehicles, which comprises storing said air vehicles within a building or a part thereof defining a generally enclosed space, controlling at least one of the temperature and humidity of the enclosed space, providing in said building or part thereof a main access door through which all of the air vehicles may enter and exit the enclosed space, and deploying one or more of said air vehicles when required.

By this arrangement, the air vehicles and their systems may be maintained in optimum condition during the storage period, particularly with regard to corrosion. The term"building"is to be construed broadly as meaning any permanent or semi-permanent structure constructed of suitable materials and/or prefabricated, to define an enclosed space within which air vehicles may be stored and manoeuvred.

Preferably, both of the temperature and humidity of said enclosed space are controlled.

The relative humidity is preferably stabilised, typically to be about 45% (e. g. 5%) relative humidity.

Preferably the pressure within the enclosed space is maintained at above ambient pressure.

In order to provide full support for the air vehicles, the enclosed space preferably also includes suitable support vehicles and/or equipment.

Preferably, the main access door is the sole entry/exit point through which the vehicles may enter and leave the enclosed space. Preferably however said main entry/exit point remains closed apart from when the vehicles are loaded into the space, or are finally removed from the space, or are on active duty.

Preferably said air vehicles are stored in an accessible fashion to allow ready access for maintenance.

The air vehicles are also advantageously stored in a manner to allow a manoeuvring space for manoeuvring for maintenance or for passage to or from the main access door.

To allow access to the controlled space for routine service and maintenance, there is preferably an airlock allowing pedestrian access into the enclosed space.

Preferably, said air vehicles are stored in stacked fashion, e. g. on two levels.

Preferably, said enclosed space is disposed adjacent accommodation for personnel, storage facilities or workshop facilities.

In another aspect, this invention provides an air offensive and/or defensive system comprising a building or part thereof defining a generally enclosed space for storing a plurality of air vehicles, an environmental control system for controlling at least one of the temperature and humidity of the enclosed space, and a main access door provided within said building or part thereof,

through which in use all of the air vehicles may enter or exit the enclosed space.

Preferably, said air vehicles are maintained in a state ready for immediate deployment.

The building is preferably resistant to attack by nuclear, biological and/or chemical weapons.

Preferably, said environmental control system is operable to maintain the pressure within said enclosed space at a pressure above ambient.

Preferably, said enclosed space includes a plurality of respective storage locations for storing each of said air vehicles, and a common manoeuvring ground area intermediate said storage locations and said main access door. Preferably each of said storage locations is dimensioned and located relative to the or each adjacent storage location to provide maintenance access. This typically will allow maintenance personnel to walk around each air vehicle.

Pedestrian access to the enclosed space may be provided by an airlock.

Preferably, said enclosed space includes means for storing said air vehicles at at least two different levels, e. g. ground and at an elevated level.

Preferably, said enclosed space includes a plurality of platforms each for supporting an air vehicle, and means for raising said platform above ground level to allow a further air vehicle to be located beneath said platform.

Preferably, said system also includes further accommodation adjacent said enclosed space. The further accommodation may comprise rooms for storage, workshop, administration and personnel.

Whilst the invention has been described above it extends to any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways, and an embodiment thereof will now be described by way of example only, reference being made to the accompanying drawings in which:- Figure 1 is a plan view of the ground and first floor of an environmentally controlled storage facility in accordance with this invention, and Figure 2 is an internal elevation taken on lines II- II of Figure 1.

Referring to the Figures, we have shown a hangar type building 10 having an environmentally controlled chamber 12 in which are stored twelve air vehicles 14 together with support vehicles and equipment 16 such as trucks and other equipment or vehicles associated with the air vehicles, and providing support to, or forming part of, the operating environment of the air vehicle. In general, no weapons would be stored in the building nor would large quantities of fluids (e. g. fuel). The hangar building 10 also includes sufficient additional accommodation facilities to store and maintain the complete fleet of twelve air

vehicles. The air vehicles can be generated from storage more rapidly than conventionally stored air vehicles because the controlled storage conditions negate the need for extensive post storage maintenance required as a consequence of current storage methods.

Within the environmentally controlled chamber 12 are shown three air conditioning units 18 which maintain the enclosed environment at a controlled temperature and a humidity of about 45% relative humidity. The units also maintain the atmosphere within the facility at a pressure slightly above ambient thereby positively to prevent the ingress of ambient air which will contain harmful moisture and other contaminants. Access to and from the enclosed slightly above atmospheric pressure environment 12 is provided by main doors 20 through which the vehicles may enter or leave, and also by an airlock arrangement 22 which allows access for pedestrians and the smaller units of equipment. The airlock 22 is of conventional form with inner and outer doors 24,26 respectively.

As seen in Figure 2, the air vehicles 14 are stored on two levels; the vehicles 14 on the upper level are carried on a hydraulically or electrically raised platform 28 which can be moved between the upper and lower storage levels.

This provides a particularly compact storage facility.

The environmentally controlled chamber is sized to accommodate the air vehicles for which it is intended, with sufficient space surrounding the vehicles to enable

maintenance to be carried out. Walkways are provided around the upper storage level to facilitate maintenance access. Because the entire chamber 12 is environmentally controlled and maintained at a pressure above ambient there is no need for partitioning or the like so that individual air vehicles can be stored in separate environmentally controlled compartments; instead the chamber comprises a single enclosed space.

Attached to the environmentally controlled chamber 12 is additional space for providing office, workshop and stores accommodation for the maintenance crew. This accommodation may be conditioned or unconditioned, but the environment will normally be sufficiently different from that in the air vehicle storage area to require airlock access.

Although the main doors 20 are shown as single doors (i. e. without an airlock), it will be appreciated that an airlock arrangement could be provided.

The system can of course be tailored to accept different sizes of air vehicles, to adjust the proportion of office space relative to air vehicle storage space.

Although intended particularly for the long term storage of uninhabited air vehicles, the facility could also be used for storing conventional air vehicles etc.

The environmentally controlled storage facility as described provides a facility whereby air vehicles may be stored for many years but can be generated rapidly in times

of need (for example peacekeeping, regional conflict, full scale war etc.). Here the facility means that the air vehicles are in a state of readiness whereby they can be ready for action within a few days. Likewise when they are no longer needed, the vehicles can be rapidly re-stored.

The absence of any cocooning or other inhibitory protection means that the air vehicles may be kept in peak condition at all times. Furthermore the facility provides easy access to each of the air vehicles without having to move vehicles to gain access to others.