Balancing act
It only took 155 years. A low-power design for airship propulsion laid out in S. Andrews’s US
patent for an ‘Aereon’ published in 1864 was borne out only earlier this year in the fi rst-ever
fl ying trial of an independent craft of this kind, of the Phoenix unmanned aerial satellite (UAS)
As the design requires no engine,
its payload fraction – the ratio
of payload to structure – is far
higher than competing airship
designs such as the Thales Stratobus,
Hybrid Air Vehicles Airlander or Airbus
Zephyr aeroplane. And that means that it
can be built for far less – up to 10 times
– than they.
Unlike the famous hydrogen-fuelled
Hindenburg dirigible that exploded in
1937, this craft was lled with nonin
ammable helium gas – at least for
now (see box, ‘Cool Tech, p29) – and is
intended to carry sensors, not people,
to the upper atmosphere. It and its
competitors are types of HAPS craft;
high altitude pseudo-satellites. These
would oat up and hang around in the
stratosphere, at 60,000ft, carrying a
10kg-100kg payload, slowly coursecorrecting
to maintain geosynchronous
orbits.
In practical terms, the six ights
achieved during the April trial of the
15m-long, 10.5m-wide technology
demonstrator inside the Trafalgar Wharf
drystack boat warehouse in Portsmouth,
though successful, fell somewhat below
those lofty goals. The 150kg craft
navigated at walking pace in and around
the still air of the 40m-high, 120m-long
building, following an autonomous ight
control program that controlled navigation,
actuation of control surfaces and
controlled top and bottom of ight path.
PARTNER CONTRIBUTIONS
• Banks Sails: materials and fuselage design
• IQE: lightweight solar cell development
• Stirling Dynamics: ight control system
software, systems integration
• TCS Micropumps: pump and valve design,
ight control actuation system design
• CPI: project management, solar cells
• MTC: ight control system hardware
• NCC: carbon bre wings and empennage
• University of Bristol: as NCC, plus stress
calculations
• UHI: chief engineer, aircraft architect,
aerodynamic design and wind tunnel testing
• University of Newcastle: hydrogen fuel cell
• University of Shef eld: wind tunnel testing
• University of Southampton: lightweight
rechargeable battery design; overall power
management system
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