DAVID LEARMOUNT / LONDON
Airships capable of lifting ultra-heavy and bulky loads could soon be used in civil projects such as bridge-building and by the military
Airship builders CargoLifter of Germany and UK-based Advanced Technologies Group (ATG) are applying new technology and lateral thinking to employ lighter-than-air vehicles in ways they have never been used.
ATG is already part of a healthy industry that meets demand for advertising blimps, but now it is planning massive, new-technology machines to take the heavy bulk cargo market where the marine industry cannot - over land.
CargoLifter was set up specifically as a logistics company, with lighter-than-air machines as its chosen tools, says chief executive Dr Carl von Gablenz. As the company has developed over the six years since it was set up, however, new possibilities for employing lighter-than-air vehicles are becoming apparent, he says. ATG's forebears have been in the lighter-than-air market for 30 years, but the company has concluded that the field offers new possibilities.
The largest of the new vehicles have dimensions that, among transport vehicles, only ships have ever reached. These are huge, sky-darkening machines that use the inert gas helium as their buoyancy provider. Some of ATG's machines are not lighter than air - they are hybrids that will lift enormous loads by combining partial buoyancy with lifting-body aerodynamics.
CargoLifter's ultimate product is a machine that looks like a conventional airship - but it is many times bigger than any of its forebears. The CL160 will be 265m (870ft) long, have a 65m diameter and be able to carry a 160t payload. Like all the CargoLifter products, however, it will be designed to be capable of acting asa mobile heavy-lift crane, not only a transport device.
Commercial product
The market for pure heavy lifting capability in more or less static situations has produced what will now be the first CargoLifter commercial product - the CL75 AirCrane. This is a massive balloon with a lifting capability of 75t. It has been ordered by an oil and gas exploration company working in the Mackenzie delta in Canada's far north and can be used either as a simple crane, controlled by mobile winching systems on the ground, or as a load-reliever or land vehicles carrying heavy drilling equipment.
By towing the balloon above them, trucks could operate on remote roads for which they would be too heavy without the CL75 bearing a high proportion of their laden weight.
The CL75 is being tested in the open air, not only inside CargoLifter's purpose-built construction hangar at Brand, near Berlin, and has enabled the company to shift design priorities for the CL160 away from static lifting to improving its heavy or bulk logistics transport performance.
Von Gablenz says that the AirCrane emerged from a market need, and CargoLifter was well placed to be the manufacturer and operator. Because the terrorist acts of 11 September have depressed business in general and the aviation market in particular, says Von Gablenz, investment in the company has slowed. The CL160 programme had to be pushed back to an estimated 2006 in-service date, so finding a ready market for the simpler CL75 has advanced the company's ability to generate earnings. Because the CL75 is a balloon, not an aircraft, it does not need licensed pilots who would have to be trained, nor certification as an aircraft, so it can be brought into operation much sooner.
Confidence boost
The side effects of this have been to increase confidence and to boost company morale, says Von Gablenz, as well as providing CargoLifter with more experience at co-ordinating with its suppliers and working with the multi-layer carbonfibre-based woven Kevlar fabrics from which all the vehicles will be constructed. Another benefit is that the additional practical experience has enabled the company to calculate much more precisely the total programme costs, which helped with investor confidence when this was a much-needed commodity.
The current issue of nearly 50 million convertible bonds has received a "positive" response, says Von Gablenz. Plans to start another construction and logistics site in North Carolina, USA, have, however, been put on hold because of the delay to the CL160 programme.
Von Gablenz explains that AirCrane will operate the CargoLifter, selling the vehicle to the purchaser and leasing it back to perform the highly specialised work that the customer wants. Tasks for which it will be suitable are bridge-building and railway or pipeline laying. The CL160 could be the delivery medium, the CL75 the lifting and positioning system.
There has been considerable interest from countries such as China and Russia, where there are large areas in which surface transport infrastructure is poor or non-existent, says Von Gablenz. Military applications could also be significant: NATO is carrying out feasibility studies of what CargoLifter products or services could do.
ATG, meanwhile, continues to sell conventional small airships for advertising and surveillance work, as does its German counterpart, the Zeppelin group. But its ultimate heavy-lift devices, the planned SkyCat series of airship/lifting body vehicles, are unlike CargoLifter's machines in that part of their lift will be provided by buoyancy and the rest by aerodynamics.
They will take off and land, albeit at low speeds, and although this disqualifies them from the sky-crane static lifting tasks that the CargoLifter devices can handle, it gives them other advantages. SkyCat's shape will not be single-hulled, but more like a blended shape based on a side-by-side pair of hulls, with the underslung freight bay between them.
The series will not have a conventional undercarriage, but a pair of hoverskirts that, upon deflation after landing, allows the craft to "kneel", enabling the freight bay to be a roll-on, roll-off (ro-ro) platform, which is particularly efficient for the carriage of cars, trucks or military vehicles. The hovercraft capability also enables the machines to take off or land on any reasonably flat surface, including water or soft ground, the main consideration then being what kind of surface the payload demands for disembarking/unloading.
Just as CargoLifter in 1999 flew a small proof-of-concept airship it named "Joey", so ATG flew its SkyKitten in 2000, proving that the three components of the design - lighter-than-air, lifting body and hovercraft - can perform together as intended, and that this revolutionary craft is also a stable vehicle in the air.
SkyCat timetable
The first of the series will be the SkyCat 20, with a payload of 19t - which is due to fly at the end of 2003 and be certificated in 2004. The next, planned to follow two and a half years later, is the SkyCat 200, able to lift 200t and with its freight bay floor designed to military specifications, according to ATG. Finally, ATG promises its customers the SkyCat 1000, with a 1,000t payload capability. ATG chief executive Roger Munk says that the 1000 will not use any unproven technology and so can be produced when the market demands.
CargoLifter's Von Gablenz, while conceding the smaller SkyCat machines will work, is less sure that the lifting body aerodynamics in a vehicle the size of the 307m-long SkyCat 1000 would be efficient.
The 1000 could be able to transport 12 battle tanks, whereas the US air force's heaviest lifter, the Boeing C-17, can only carry two. Normally tanks have to be shipped by sea, as the US Army's armoured vehicles were for the Gulf War in 1990/01. The Pentagon is taking a great interest in the SkyCat series and in CargoLifter's capabilities as a total logistics organisation.
Source: Flight International
