Giant 5-year-mission aerial wing-ship to fly in 2011

US military plans to build a mighty unmanned wing-ship able to cruise the stratosphere on flights lasting five years have moved forward with the announcement that flight tests of the "Vulture II" prototype are expected to commence next year.

Vulture II is being produced by US aerospace mammoth Boeing, building on its previous SolarEagle craft. Controversial British gov-boffinry selloff fatcat bonanza firm QinetiQ is also on board, bringing expertise gained during its "Zephyr" programme. The Zephyr is currently the official record holder for longest flight, having remained airborne for just over two weeks above Arizona last summer.

SolarEagle, Zephyr and now Vulture II all work along the same lines. The planes are propelled by electric motors. Solar panels on the upper surfaces generate a surplus of power over and above that needed for propulsion, systems and payload, which is used to charge up batteries or fuel cells which supply power through the hours of darkness.

Having no need to refuel and few moving parts, it is thought that such unmanned sun-planes could cruise for very long periods high in the stratosphere, taking on roles which today are performed by satellites or large manned aircraft working in shifts – both very expensive. The simplest of these tasks is relay of communications to and from ground units, lower-flying aircraft etc: permanently patrolling sunbirds might also take on surveillance missions if they could manage the heavier and more power-hungry payloads involved.

The Vulture II (Vulture I saw several design studies but no flying hardware) is to have a 400-foot wingspan and is expected to eclipse the Zephyr straight off with an inaugural flight lasting 30 days. A federal sole-sourcing notice regarding facilities for the flight tests issued on Wednesday tells us:

Period of performance of Phase II ["prepare for and conduct flight demonstrator air vehicle flight testing"] is anticipated to begin August 15, 2011, and continue through the completion of flight testing, currently expected to be completed during the third quarter of fiscal year 2014.

Evidently an actual five-year test flight is not on the cards, then: a one- or two-year trial is the best we can expect. We also learn that Vulture II will be based in New Mexico for the trials.

This indicates that the huge sun-powered wingship, in common with the Zephyr, may not be able to stray too far from the Equator. The Zephyr's record-busting flight last year took place – at midsummer – in one of the most southerly locations that QinetiQ could feasibly use, therefore in just about the most advantageous possible conditions for solar power.

Originally there were aspirations for a crafty "Z-wing" configuration in which the Vulture wing would have three hinged sections (which would take off separately and then dock together in flight) and thus would be able to tilt parts of itself towards the sun. This might have permitted it to operate at higher latitudes for more of the year: but the idea didn't make the cut and Vulture II will be a relatively conventional craft, perhaps unable to operate much further north than the southern USA.

One need hardly add that the Vulture comes to us courtesy of DARPA, the paradigm-punishing technological topsy-turvination boffinry bureau of the US military. Just in case Vulture doesn't work out, the agency is also working on a huge solar-powered strato-airship, potentially able to track every movement occurring across hundreds of miles of territory beneath its all-seeing radar spyeye. ®