A new UK-built endurance aircraft known as Phoenix has made its public debut following indoor flight testing at the Drystack facility in Portsmouth.
Designed to operate at high altitudes for extended periods, the prototype vehicle has a 15m-long fuselage filled with helium and a wingspan of 10.5m. It propels itself using variable buoyancy, constantly shifting its weight to be lighter or heavier than the surrounding air, which creates thrust. This oscillation in weight is achieved by sucking in and compressing air to descend, then releasing that air to increase buoyancy.
“The Phoenix spends half its time as a heavier-than-air aeroplane, the other as a lighter-than-air balloon,” said lead designer Andrew Rae, Professor of Engineering at the University of the Highlands and Islands. “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 aeroplane forwards and is assisted by the release of the compressed air through a rear vent.”
A battery fed by solar cells powers the propulsion system, allowing the aircraft to fly autonomously at extreme altitudes for extended periods of time. According to its developers, Phoenix could operate as a pseudo-satellite, launch microsatellites into near-Earth orbits and carry out surveillance mission, ultimately flying as high as 20,000m
“Vehicles based on this technology could be used as pseudo-satellites and would provide a much cheaper option for telecommunication activities,” said Rae. “Current equivalent aeroplanes are very complex and very expensive. By contrast, Phoenix is almost expendable and so provides a user with previously unavailable options.”
The three-year project to get Phoenix to this stage has involved multiple partners across academia and industry, including the Universities of Bristol, Newcastle, Sheffield, Southampton, and the Highlands & Islands, as well as the Manufacturing Technology Centre (MTC) and National Composites Centre (NCC). Having now demonstrated the viability of variable buoyancy as a propulsion system, the team is now hoping to partner with major manufacturers tor the next phase of development.
I absolutely love this great work you folks did here! This is a wonderfully beautiful concept, almost too simple to work, but work it shall.
What very clever yet simple idea, hope we can industrialise it ASAP. I am sure design (re-)engineers from China are watching this video avidly as we speak!
Brilliant concept using Solar, Compressed air for rise/dive. Now they need to look at a 30,000 meter height and a circular pattern for a communication system to transmit Cellular/TV/and Weather detection/forecasting to a huge area below, for areas that are remote or difficult to communicate with.
Keep it up and do not let it out of the UK [no matter how much some one wants the technology…keep your hands on all the IP at all times- to much has been sold/given away in the past]
Such a tiny area of solar cells! Why not triple the capacity with a dorsal strip?
Sadly lacking in technical detail.
What speed can the balloon achieve?
Winds at 20,000m are significant, can the balloon really overcome these?
Launching micro-satellites requires them to go HIGH and FAST. ‘High’ is the easier part of this problem requiring much less fuel than the ‘fast’ piece.
‘Several days’ endurance isn’t impressive. ‘Several months’ might be.
Excellent concept – what payload can it carry?
Just a thought; Bearing in mind the potential scarcity of Helium, (at least until someone actually does start a fusion reactor). And also keeping in mind the autonomous and unmanned nature of the aircraft, Why Helium? Wouldn’t Hydrogen lift better and be cheaper and have better sustainability? Regards the flammability, the aircraft is surely going to be the cheaper part of the package, the sensor pack or repeater could be lowered by parachute if there were a failure.
This clever idea works, as demonstrated.
These inappropriately negative comments by Ekij are pompous. Do better if you can
The concept of using variable density to achieve lift sounds novel and innovative, even assisted by air jet.
I would too be interested to know what the potential load capacity/flight ceiling was, even for this prototype.
Questions about speed and ability to keep on station are good and interesting but, I would expect, would be something that the trails of the prototype will help answer; these will help determine the possible applications (and sizes) of the system.
I suspect that the use of hydrogen as the lifting gas could be beneficial in increasing the flight ceiling but would think that there might be significant issues with leakage – especially over long flight duration.
I think this is a radical innovation and I wish them well in any disruptive implementation