Feeds

Airship 'Sky Tugs' ordered from Lockheed for Canadian oilfields

P-791 military hover suck-blimp gets civil application

Top 5 reasons to deploy VMware with Tegile

The famous P-791 prototype airship - built last decade for a military transport programme which eventually came to nothing - is to give birth to new, mighty commercial versions of itself with Canadian financial backing.

Alberta-based private company Aviation Capital Enterprises says it has inked a deal with US aerospace colossus Lockheed, builder of the P-791, to "design, develop, build, flight test and Federal Aviation Administration certify a family of hybrid aircraft". The first ship, dubbed "SkyTug" and able to lift 20 tons, is to be delivered in 2012. Further versions are to scale up to "several hundred tons", apparently.

A hybrid air vehicle isn't a conventional lighter-than-air dirigible, whose weight is entirely supported by the buoyancy of its lifting gas. A hybrid's gas only counteracts part of its weight: in order to get airborne, the SkyTug will swivel its propellors downwards for vertical thrust. Once it starts flying forward its hull will generate dynamic lift just as an aeroplane's wing does, allowing the props to be swivelled horizontal for greater cruising speed.

According to Aviation Capital, the fully vertical-takeoff-and-landing (VTOL) capable SkyTug will provide "greater payload and range at a fraction of the cost of a helicopter". The larger ships that will follow apparently won't be fully VTOL - they'll require something of a run-up on the ground to generate dynamic lift and get airborne, rather as an aeroplane does.

However the big ships aren't expected to need massive runways: they'll be able to land and take off from "unimproved surfaces and water". This will be achieved by the cunning air-cushion undercarriage which is such a novel feature of the P-791: rather than wheels or skids, the airships will move about on the ground supported on air blown down through big skirt assemblies, just like a hovercraft.

The fact that a hybrid ship is heavy helps to avoid one of the main headaches of unloading an airship at a place where there's no way of taking on water ballast. A traditional airship struggles to manage such operations, as once the payload is gone the ship becomes uncontrollably buoyant and is likely to soar up through its "pressure height" - the point at which the lifting gas has expanded to fill the entire envelope - and lose most of its helium via the automatic safety valves (or burst). Helium being expensive, this is not ideal.

P-791 style ships have another ace up their sleeve for unloading, in that the hover undercarriage can be switched from blow to suck, thus sticking the ship firmly down on the ground (or sea) even if it might have become a bit flighty during unloading. This is also handy for preventing the vessel being blown around by the wind.

The P-791 itself was originally built by Lockheed in 2006 as a contender for the US military's proposed "Walrus" project, intended to deliver a brobdingnagian airship capable of hauling an entire US army combat battalion of 500+ troops - plus all their vehicles, heavy weapons and other kit - in one lift. But a heavy-lift airship needs a lot of gas, and this in turn means that "pressure height" can't be too high or the envelope will have to be unfeasibly huger still.

Thus the Walrus was specced for 10,000 feet maximum altitude, which was realistically a show-stopper for the military - even shoulder-launched missiles can reach that high, and the ship would have been a very easy target.

Beginner's guide to SSL certificates

More from The Register

next story
LIFE, JIM? Comet probot lander found 'ORGANICS' on far-off iceball
That's it for God, then – if Comet 67P has got complex molecules
Rosetta probot drilling DENIED: Philae has its 'LEG in the AIR'
NOT best position for scientific fulfillment
'Yes, yes... YES!' Philae lands on COMET 67P
Plucky probot aces landing on high-speed space rock - emotional scenes in Darmstadt
HUMAN DNA 'will be FOUND ON MOON' – rocking boffin Brian Cox
Crowdfund plan to stimulate Blighty's space programme
THERE it is! Philae comet lander FOUND in EXISTING Rosetta PICS
Crumb? Pixel? ALIEN? Better, it's a comet-catcher!
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
Post-pub nosh neckfiller: The MIGHTY Scotch egg
Off to the boozer? This delicacy might help mitigate the effects
I'M SO SORRY, sobs Rosetta Brit boffin in 'sexist' sexy shirt storm
'He is just being himself' says proud mum of larger-than-life physicist
prev story

Whitepapers

Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Choosing a cloud hosting partner with confidence
Download Choosing a Cloud Hosting Provider with Confidence to learn more about cloud computing - the new opportunities and new security challenges.
New hybrid storage solutions
Tackling data challenges through emerging hybrid storage solutions that enable optimum database performance whilst managing costs and increasingly large data stores.