The Hybrid Air Vehicles product range consists of the following model ranges:
- The HAV304. This model forms the platform for the LEMV programme and while optionally manned, is optimised for unmanned, persistent surveillance.
- The remainder of the product range is called AIRLANDER and comes in a number of configurations:
- Surveillance – manned surveillance with optionally pressurised mission modules, offering up to five days persistent surveillance
- Heavy Lift, offering a variety of configurations including 20, 50 and 200 tonne payloads.
The AIRLANDER features the following:
- AIRLANDER is designed to be the safest form of air travel. The vehicle does not stall, lands on any reasonably flat surface and has a take-off and landing speed of around 40 knots. It is fitted with four propulsion units and with close on 10,000 Shaft horsepower (SHP) for the 50 tonne variant it has sufficient power and range to deal with the most challenging environments;
- A vehicle that uses a combination of buoyancy (helium gas) and aerodynamics (the shape of the body) to generate lift. This “hybrid” is in essence an aircraft with some inherent buoyancy, similar to a lifting body (a vehicle in which the body itself produces lift). This design creates the perfect balance between economic flight (typically associated with airships), operational flexibility (typically associated with helicopters), range and payload;
- The AIRLANDER range consists of two groups – Surveillance and Heavy Lift. The surveillance vehicle can operate at up to 20,000 feet (6,096 meters) for up to 21 days unmanned and 5 days manned. The Heavy Lift version is designed for transportation of passengers and cargo;
- A key attribute is operational flexibility. In addition to Conventional Take-Off and Landing (CTOL), the vehicle is also capable of Vertical Take-Off and Landing (VTOL). It can, for example, hover like a helicopter while hoisting up to 40% of its designed payload – 20 tons in the case of the AIRLANDER 50. However, the range and payload of the vehicle far exceeds that of helicopters - most rotary aircraft have an operating radius of 150 – 300 nautical miles (278 – 556 kilometres), whereas the AIRLANDER 50 has a range of 2,600 nautical miles (4,815 kilometres);
- The AIRLANDER excels in operational efficiency. For example, the Heavy Lift version requires little or no infrastructure to operate. For CTOL it requires no runway and less than four hull lengths to take off or land. The surveillance model, currently being built for the US Army, was rated by the Congressional Budget Office as “having a payload-duration about 80 times that of the Grey Eagle” (the next best competitor);
- The Heavy Lift version uses an innovative landing system called Air Cushion Landing System (ACLS). This enables the vehicle to land on almost any reasonably flat surface, including land, water, ice and snow. Suction can also be used to ensure the vehicle remains stationary during loading and off-loading. This lack of reliance on infrastructure allows the vehicle to operate point-to-point (from source to site), offering major benefits in terms of time, risk reduction, operating costs and the environment.
The AIRLANDER is a hybrid air vehicle and derives its flight capability from a mix of aerodynamic lift and helium buoyancy.
The envelope is constructed from a laminated fabric that offers strength, a gas barrier and protection against the elements. It also has an internal catenary system supporting the payload module. The hull’s aerodynamic shape, an elliptical cross-section allied to a cambered longitudinal shape, provides roughly 40% of the vehicle’s lift. The internal diaphragms required to support this shape allow for some compartmentalisation, further enhancing the fail-safe nature of the vehicle. Multiple air-filled ballonets located fore and aft in each of the hulls form part of the automated pressure management system.
On vehicles that operate from a set base, simple profiled pneumatic tubes on the underside of the two outer hulls are used. This simplified landing system saves weight and is used mainly on the unmanned surveillance vehicles, further increasing their endurance.
The Heavy Lift versions of the AIRLANDER uses an innovative landing system called the Air Cushion Landing System (ACLS). This enables the vehicle to land on almost any reasonably flat surface including land, water, ice and snow. The ACLS is also used, in conjunction with the bow thruster, to simplify manoeuvrability on the ground, reducing the need to operate the main propulsion units. The ACLS can also be used to create suction to ensure the AIRLANDER remains stationary during loading and off-loading.
The landing systems are deflated and ‘sucked-into’ the hull for a clean in-flight profile. The power units used for inflation / deflation are shared with the ballonet fans and managed by the hull pressurisation system.
Since the AIRLANDER is effectively an aircraft with inherent buoyancy, it is fitted with significant power plants that are more akin to those found on fixed wing aircraft. While most airships have less than 1,000 SHP (Shaft Horsepower), the AIRLANDER 50, for example, will have four turbine engines generating around 10,000 SHP.