Long, silver, cigar-shaped - had the 81m Dragon Dream airship prototype shaken off its tethers when it was set loose from its hangar on 4 July 2013, UFO sightings over Tustin, California would have gone through the roof. Dragon Dream was funded by the Pentagon through a programme called Project Pelican to the tune of $35m in R&D funds. It was a half-sized prototype of the future Aeroscraft, a massive rigid-hulled hybrid airship destined to deliver tons of cargo to even the most remote of military outposts.
Military transport airships fell out of favour when winged aircraft and helicopters became capable of carrying much heavier payloads. But because Worldwide Aeros' lighter-than-air helium solution only needs to overcome drag in forward flight, not generate lift, it could operate at less than a third of the fuel consumption of conventional vehicles on a per ton/mile basis, hence the Pentagon's interest. And the massive cargo capacity of the proposed Aeroscraft easily surpasses anything offered by conventional transport.
The major problem with airships for cargo applications has to do with arrival at destination. How do you remove a payload from a helium filled aircraft and keep the vehicle grounded without first weighing it down with compensating weight, like sandbags? This external ballast exchange requirement would mean ballast and manpower need to be pre-deployed at the destination, reducing the flexibility to land virtually anywhere.
Aeros' CEO Igor Pasternak came up with the solution of an internal buoyancy management system given the proprietary name Control-Of-Static-Heaviness (COSH). It uses a similar ballast management system to that which enables submarines to ascend and descend vertically underwater, while also having the ability to use control surfaces when moving forward.
Aeros has completed construction of a prototype cargo airship for the US military.
The COSH system compresses the helium down into high pressure envelopes (HPEs), which reduce the helium static lift. The vacuum pressure created within the rigid surround - known as the aeroshell -- draws air into expansion chambers which provide additional ballast. The closed system is reversible via pilot touch control, so through pressure management static lift can also be regulated and adjusted. This also greatly reduces the infrastructure and labour needed on the ground.
The 2013 out-of-hangar testing of the Dragon Dream scale prototype demonstrated the integration of this COSH technology with other sub-systems. The US Federal Aviation Authority (FAA) issued an experimental certificate in August and September, which allowed test pilots Corky Belanger and General Raymond Johns to perform multiple takeoffs and low-elevation landings while completing integration testing of all vehicle sub-systems. They accomplished all of their objectives and achieved the desired system performance, successfully demonstrating vertical takeoff and landing (VTOL), hover, transition to flight and ground manoeuvres, and internal ballast control system operation including demonstration payload offloading.
Despite being half the proposed eventual size to reduce costs, Dragon Dream was still large enough to integrate the COSH buoyancy management system alongside other vehicle sub-systems needed when moving cargo to austere environments, such as an internal rigid structure, vectored thrust, low speed control, air-bearing landing system and fibre optic avionics.
Just a month after Dragon Dream's maiden outdoor flight, the roof of Worldwide Aeros' wartime hangar collapsed, damaging it beyond repair, but it by then had already fulfilled its purpose.
Aeros is now moving forward on the development of an initial fleet of two full-scale Aeroscraft models, this time mainly for the commercial market but with one eye still focussed on military deployment. The ML866 variant will carry a 66 ton payload, and the ML868 250 tons - the equivalent of three Abrams tanks and their crew - both at speeds of up to 120 knots and an altitude ceiling of 12,000 feet.
An initial fleet of 22 vehicles is planned; four in the 66-ton configuration and 18 in the 250-ton configuration, though the actual numbers of each may vary slightly depending on demand. The first 66 ton vehicle's introduction is planned for 2017, and Aeros expects the initial fleet to be in global operation by 2020-21.
The airships have attracted transatlantic interest - it was recently announced that the European Consortium of Aeroscraft Operations (ECAO) signed a memorandum of understanding (MOU) defining an independent study on the Aeroscraft for military, humanitarian, and commercial projects.
"We expect the commercial markets will be the primary opportunity over the military market, but both will have substantial big, heavy lift and general container cargo shipping needs, as well as desire to reach more austere or expeditionary environments," said Aeros' director of communications, John Kiehle.
"We expect disaster response utilisation will be irregular and unpredictable, but an operational priority whenever required. However, the US military will always be customer number one because of their mission and invaluable support during technology incubation and demonstration."
While travelling slower than fixed-wing aircraft, the Aeroscraft could deliver logistics solutions that are faster overall than rail, truck and maritime delivery, as the cargo can be delivered directly to its destination, rather than via intermediate transfer points. Industrial sectors most likely to benefit from Aeroscraft include traditional and alternative energy - for instance delivering turbines to a remote wind farm - aerospace, mining, agriculture and cold-chain logistics, as well as high-value consumer goods in numerous sectors.
On the military cargo side the Aeroscraft offers a mission flexibility existing modes of transport cannot provide, falling between sealift and airlift in terms of speed and cost. Completely independent of infrastructure, it could be deployed virtually anywhere, not just for delivering heavy cargo but also supporting humanitarian missions and disaster relief response, providing medical logistics support and supporting the US Army's environmental stewardship programme.
If Aeroscraft gets off the ground - both physically and metaphorically - the US military could be entering a new era of the blimp.