With a team effort, the first ever large-scale aircraft powered by variable buoyancy propulsion was developed and flown. Dubbed the Phoenix, it is designed to repeatedly transition from being lighter than air to being heavier than air so thrust is generated to propel the craft.
The team includes a partnership of universities and companies, and was led by Andrew Rae, professor of engineering at the University of the Highlands and Islands Perth College UHI Campus.
“The Phoenix spends half its time as a heavier-than-air airplane, the other as a lighter-than-air balloon. The repeated transition between these states provides the sole source of propulsion. The vehicle’s fuselage contains helium to allow it to ascend, and also contains an air bag which inhales and compresses air to enable the craft to descend. This motion propels the airplane forwards and is assisted by the release of the compressed air through a rear vent,” says Rae. “This system allows the Phoenix to be completely self-sufficient. The energy needed to power its pumps and valves is provided by a battery, which is charged by lightweight flexible solar cells on its wings and tail. Vehicles based on this technology could be used as pseudo satellites and would provide a much cheaper option for telecommunication activities.”
The prototype craft is nearly 50 ft. long and has a wingspan of approximately 34 ft. The Phoenix successfully flew a distance of almost 400 ft. during its indoor trials at the Drystack facility in Portsmouth this March. The project has been a three-year journey to prove the viability of a variable-buoyancy powered aircraft.
According to the team and New Atlas, the Phoenix may also be able to operate on the edge of space and act as a launch platform for micro-satellites. The ultimate goal for this beast to get it to operate at an altitude of 66,000 ft., where it could stay afloat for several days at a time.