TYPE: Technology demonstrator.
PROGRAMME: Announced August 2003; promotion began at NBAA Convention, Orlando, Florida, October 2003, at which time early work had begun on construction of a prototype.
DESIGN FEATURES: Fuel-less propulsion system employing two gravity-related phenomena: buoyancy, as utilised by lighter than aircraft; and gravitational attraction utilised by gliders.
Twin pontoons (booms) with cabin between and variable geometry (90° backward sweeping) wings outboard; rear fins and tailplane, latter with two differentially capable 'allerons' for roll control in addition to conventional pitch control. Reversible (dual function) wind turbine on outboard side of each pontoon (principally for steering) and behind cabin (main). Rigid pontoons are stressed to contain a vacuum for optimum buoyant lift, although early aircraft expected to rely on several helium-filled bags within pontoons (this also safety measure in the event of vacuum failure).
Long-distance flight accomplished by repetition of the flight cycle in which the aircraft rises almost vertically and then gliders.
1) Aircraft at horizontal rest; compressed air tanks charged from previous cycle; heavier than air because of large amount of compressed air aboard.
2) While at reast on the ground, interior bladders are fully inflated with helium due to vacuum in cells from previous cycle, maximising bladder displacement (equal to max altitude) and increasing lift dramatically due to extreme low pressure of expanded helium because of the vacuum, but aircraft is still heavier than air because of large supply of compressed air.
3) Take-off. Compressed air powers pneumatic turbines (on sides of pontoons) that are pointed downward to provide ground effect lift, and compressed air ballast weight is rapidly discharged, making craft lighter than air. Approximately 50 per cent of compressed air is used to power turbines and to discharge ballast weight in take-off process. Attitude of aircraft becomes almost vertical as it climbs and turbines on sides of pontoons revert to the horizontal. In part, this is accomplished by using compressed air from nose of aircraft first, making nose lighter than rear so it pitches upward after ground has been cleared.
4) Aircraft ascends to 15,240 m (50,000 ft) and, as it rises in almost vertical nose-upward flight, a small amount of compressed air is used to maintain flight attitude and to make aircraft lighter at the same time. This process provides little propulsion, as aircraft is rising by being lighter than air.
5) At full height, compressed air is injected into exterior ridged cell chamber, reducing helium bladder volume; descent begins. Compressed air from very-high-pressure storage cylinders drives pneumatic motors (by expansion from higher pressure to lower pressure) that power air compressors to bring new air in from surrounding environment. New incoming air, and now-expanded lower pressure compressed air, after driving the pneumatic motors, both go into cells to compress helium within gasbags due to higher pressure than bagged helium. In this process, new weight is added to aircraft and weight of compressed air from cylinders is conserved (kept aboard aircraft); otherwise, there would be no increase in weight of aircraft if new air is not brought aboard. This is a key point to understanding the ballast process.
6) Wings sweep back to proper angle to accomplish steep dive to pick up speed quickly as aircraft noses downward sharply.
7) Once a downward and forward motion is achieved wind turbines begin operation in order to bring in compressed air from atmosphere to continue to make aircraft heavier, so that it does not reach equilibrium and stop descending at a lower altitude as surrounding air's density and lifting capacity increases.
8) Wings reduce sweep as aircraft falls into thicker air (40:1 glide ratio).
9) Exposed wind turbines recover energy from slipstream and continue to recharge compressed air tanks until filled.
10) After compressed air is recharged and aircraft is as heavy as it was when on ground, power from wind turbines is used to pull vacuum back into cells to inflate helium bags fully to provide lift to stabilise aircraft at low altitude; and exterior ridged cell chamber is drawn down to vacuum.
11) Cycle repeats, with discharge of 50 per cent compressed air to provide propulsion and to make aircraft lighter than air again to rise to high altitude.
12) Landing technique is similar to take off as compressed air is used to provide downward thrust to set craft down vertically. However, minimal compressed air consumed to conserve weight to keep craft heavier than air.
No weights or dimensions have been disclosed.