Australia, the nation which brought you a flying farm-tractor called the Airtruk and a stagger-wing trainer called the Eagle, is at it again. Innovation is alive and well down under, despite market conditions which would seem to discourage aviation ventures.
"If you could build aeroplanes out of gum trees, Australia would be a good place to build them," says Don Adams, designer of the Seabird Seeker, an unconventional light spotter aircraft.
Adams believes high Australian manufacturing, labour and materials costs, combined with government charges, a lack of development incentives and the limited market offered by a small population, have restricted the prospects of his own aircraft and other innovative projects such as the all-composite Eagle.
Australia, however, has become something of a catalyst for designers proposing even less conventional flying machines - among them wing-in-ground-effect (WIG) projects, a radical vertical take-off and landing design, and a futuristic lighter-than-air concept. These projects have a common desire to attract Australian venture capital.
Among the more adventurous projects is the Advanced Air Vehicle (AAV) unveiled by Begul Aviation of Ballarat, Victoria, at Airshow Downunder in February 1999. The AAV is a twin-hulled semi-rigid airship. Although effusive about the economic advantages of such a venture to the city of Ballarat, Begul's promotional material is possibly insufficient to attract the serious investor, lacking detail on design, manufacturing, financial and operational aspects.
Judge for yourself. The brochure says the twin hulls are constructed of "Kevlar and multi-layer co-extruded laminates which can be coated with radar-absorbent materials. Each contains 125,000-500,000ft³ (3,550-14,186m³) of helium in no fewer than 10 separate cells. The hull's patented aerofoil design provides lift In the same way as conventional fixed-wing aircraft. The helium contributes to buoyancy. It provides the additional lift that allows the AAV to carry more, to hover, to stay in the air longer at lower running costs."
According to balloonists, one cubic metre of helium supports one kilogramme of gross weight. The largest AAV model, supported by over 141,000m³ of helium, would thus support a gross weight of over 141t; of which Begul claims 18t would be payload. Cruise speed is quoted as 75-80kt, depending on the forward propulsion unit.
Begul may be more successful in attracting investment than Perth, Western Australia-based Sadleir VTOL Aircraft. Since about 1991, the firm has been marketing unconventional VTOL aircraft. Sadleir's designs show vertical lift being provided by a ducted fan housed horizontally within a delta wing. This exhausts through underwing ducts with rotating vanes which Sadleir's drawings indicate would be connected to a "joy stick". In forward flight, upper and lower doors would close to provide a conventional aerofoil. Sadleir foresaw vehicles with top speeds exceeding Mach 1, and gross weights reaching 50t.
Although copious, the technical literature failed to gain the unanimous endorsement of aerodynamicists and aeronautical engineers. Sadleir did, however, produce and circulate video footage of tethered trials of a small model of the lifting device. These revealed convincingly that the device's thrust exceeded its weight. Lately the company has not been contactable.
Australian wing-in-ground-effect ventures appear to be faring better. Cairns, Queensland-based Flightship Ground Effect says it is coming to Europe for customer demonstrations of its eight-seat FS8 WIG aircraft in late February, and claims "overwhelming" orders. Although the company plans to build the craft in Cairns, the first FS8 is being constructed in Germany. Meanwhile, Flightship has flown a small two-seat proof-of-concept prototype at Cairns.
The all-composite FS8 will be powered by a 7.2 litre (1.9USgal), 335kW (450hp) General Motors V8 engine driving two four-bladed propellers, and is expected to cruise at 86kt (156km/h). Maximum take-off weight will be 3,400kg (7,490lb), and maximum payload 750kg.
As WIG vehicles are hybrid air and water craft, the FS8 is considered by the regulatory authorities to be a high-speed boat, and the crew will require marine qualifications. The sea-skimming craft will be able to take off and land in wave heights up to 0.5m (1.6ft) and cruise above waves up to 2m tall in wind velocities of up to 30kt.
Source: Flight International
