The return of the Zeppelin?

The Graf Zeppelin

One of the most intriguing predictions in the usual end-of-year rush was that we could soon be taking holidays thousands of feet in the air. By 2030, claimed a report for Thomson Holidays, giant, eco-powered airships, containing entire resorts, will be floating through the skies. It seems fantastical, but you don't need to look 20 years into the future to see the airship making a comeback. In fact, these long-neglected craft are already undergoing a renaissance that could transform the way we travel.

The concept of lighter-than-air flight is not, of course, a new one. What stalled its development is something known in the business as "the H-Factor" – "H" in this case standing for "Hindenberg". Even though there had been dozens of airship disasters before, the devastating image of a transatlantic Zeppelin engulfed in a fireball at Lakehurst, New Jersey, in May 1936 shattered public confidence and spelt doom for the golden era of the airship. Programmes worldwide were axed and, with war imminent, the funding poured into heavier-than-air craft. The great airships were consigned to the scrapheap: Goering had all the remaining German Zeppelins salvaged for their Duralumin; the scrap from the R-100, the leading British airship, was sold for £600.

The concept of the airship lived on, using non-flammable helium, rather than the hydrogen that buoyed the Hindenberg, but in diminished form. During the Second World War, America deployed blimps for surveillance and patrol, and since then a few small airships have seen service, such as the Sentinel series and recently the Zeppelin NT. These, however, carry only a handful of passengers and are limited mostly to advertising and sightseeing.

In other words, at a time when our skies are filled with Eurofighters and Dreamliners, airship technology has remained frozen with the Fokkers and de Havillands. All that, however, is about to change. This is partly down to new materials: high strength-to-weight fabrics mean that hulls on the scale of the old Zeppelins can be built without the need for rigid internal structures, while the payload modules (still quaintly called "gondolas") are now made of Kevlar and, foreseeably, carbon fibre and graphene.

Partly, too, it is because of the inexorable pressure of fuel costs and emissions controls. When operating an aircraft, fuel is the single largest cost – but with its lift provided by the gas in its hull, a conventional airship only needs to propel itself forward, not upwards. That means lower fuel burn and, in turn, lower emissions. Flying at between 4,000 and 5,000ft, where emissions are less harmful anyway, tomorrow's airships will generate just a tenth of the CO emissions of a commercial aircraft. New power sources, such as hydrogen fuel cells, bring the vision of a zero-emission craft within reach – but even with today's technology, a fleet of hybrid airships operating out of Heathrow could meet the predicted growth in air traffic, reduce the airport's overall emissions to the legal level and eliminate the need for a third runway altogether.

Fundamentally, however, the revolution is in design. Ever since the Wright Brothers, people have been looking for ways to marry the gas lift of an airship and the aerodynamic lift of an aeroplane. Now, at last, such hybrids have arrived. One design, the Boeing SkyHook, takes a conventional cigar-tube hull and attaches rotary blades to outriggers to create a helicopter-airship hybrid. Two others, the British SkyCat and its lookalike from the American firm Lockheed, turn the hull itself into a flying wing, creating a hybrid of plane and airship. Scale models of these have already flown, and several other designs are gestating on drawing boards.

These hybrids change the aeronautical game. The Graf Zeppelin was 810ft long, with 20 sleeping berths and 36 crew. A hybrid airship of that length could carry 500 tons of cargo or, in theory, 5,000 passengers. Of course, technical challenges remain: the flying-wing shape induces extra drag, and having the centre of weight close to the centre of lift reduces stability. But trials show the design to be remarkably stable – and, indeed, intrinsically self-correcting.

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What a fascinating idea.