DARPA’s New ‘Pelican’ Promises High-Tech Airship
DARPA’s ambitious Walrus airship may be dead in the water, but some of its high-tech concepts could still be taking to the air. Having received a cash infusion from DARPA, the airship company Aeros hopes that its Pelican craft could provide heavy-lifting capability from a lighter-than-air craft.
One of the major selling points of the Pelican is that it could solve a key problem that has dogged airship design having to do with buoyancy. As the aircraft’s motors burn fuel, it becomes lighter and starts to float upwards. To offset this, expensive helium gas is released from the airship. The Pelican would take a different approach to this problem, according to Aviation Week:
[The Pelican is] a 230-ft.-long, 600,000-cu.-ft. demonstrator for its rigid-aeroshell, variable-buoyancy (RAVB) technology. Inside the shell, comprising a load-bearing frame of carbon-fiber trusses covered by thin-gauge rigid panels, will be a membrane to contain the helium lifting gas. Inside that membrane will be pressurized pump-fed tanks. More helium under pressure in the tanks makes the vehicle heavier, and less makes it lighter.
In some of Aeros’ existing craft, this has been achieved with donut-shaped compartments that fit around the airship as pictured above. Using vectored thrust propulsion, this could allow the Pelican could take off and land vertically, hover, and land with little help from a ground crew. The company claims that the Pelican could even move cargo on and off ships without having to land. Aeros is planning a demonstration flight in 2012-2013, and has (as yet unfunded) hopes for a 60-ton capacity craft in the near future. But given the tenuous nature of military research, those plans could easily float away.