1,000t-capacity aircraft to be capable of carrying complete unit "from fort to fight"

Airship designers have been briefed on the US Defense Advanced Projects Agency's (DARPA) Walrus programme to demonstrate the feasibility of an ultra-large hybrid aircraft able to carry a complete army unit "from fort to fight".

Under the $10 million Walrus advanced technology demonstration (ATD), DARPA plans to flight-test a "significant-scale" lifting airship in 2008 with a payload capability of around 30t, comparable with a Lockheed Martin C-130. The full-scale objective air vehicle would be capable of carrying 500-1,000t over an 11,000km (6,000nm) range.

The goal of the ATD is to demonstrate the military utility of a large cargo airship combining buoyant and aerodynamic lift; capable of vertical take-off and landing from land and sea, and maintaining hover position during loading and unloading; and able to operate from unprepared sites and ship's decks, and withstand adverse weather.

DARPA's concept involves the deployment of a US Army combined-arms unit, battle-ready to fight for at least three days, direct from the continental USA to the theatre of operations within 96h. This would circumvent the need for slow sea transport, or to break up the unit to deploy it by fixed-wing aircraft and helicopters.

Advances in envelope and hull materials, buoyancy and lift control, drag reduction and propulsion make the concept feasible, DARPA says. Technologies to be investigated in the initial study phase include vacuum/air buoyancy compensator tanks, which provide buoyancy control without ballast, and electrostatic atmospheric ion propulsion.

A draft solicitation for the Walrus ATD was released at the end April. DARPA plans to award multiple contracts for the initial 12-month concept-definition phase, after which a maximum of two teams will proceed into preliminary design, with one to be selected in early 2007 to build and test the demonstrator. An industry day in late April was attended by airship builders such as the UK's Advanced Technologies Group and US firm Aereos Aeronautical Systems, as well as entities working on hybrid aircraft concepts such as Aereon, Millennium Airship, Ohio Airships and Quantum Aerostatics.




Source: Flight International