Airships are on the rise again. For 60 years or more airships have been mostly a novelty but things are looking up for this neglected way of getting about.
At the start of the 20th century airships seemed the natural choice for air travel. The world's first airline, the German DELAG, flew airships not planes and when the Empire State Building was built it included an airship terminal.
For quite some time lighter-than-air airships were streets ahead of heavier-than-air aeroplanes in range and capacity. The good times didn't last.
An airship flies because it is full of something even less dense than air. The earliest airships used hydrogen for this job as it is the lightest gas and easy to obtain. Unfortunately, it is also inflammable, tragically demonstrated in 1937 when the German airship Hindenburg burned to the ground while docking in New Jersey after a trans-Atlantic flight.
When the United States got into airships it decided to use helium instead. Helium is a little heavier than hydrogen but won't burn. It's also harder to come by but it just so happened that the first useful source was discovered underneath the American Midwest.
American designers therefore had a safer way of filling their airships than their European counterparts.
Helium wasn't enough to stop calamity striking, though. The small fleet of zeppelins built by the US Navy were all destroyed in bad weather with great loss of life. Perceived unreliability coupled with the rapid improvement of heavier-than-air flight spelt the end for airships.
Now they are beginning to make a comeback, helium-filled and not yet on such a lavish scale as the airships of yesteryear. Airships may have been largely absent from our skies for decades but they haven't been from drawing boards, where many improvements have been made.
Today you can go sightseeing in a Zeppelin NT (new technology) in Germany and the US. Last year British company Hybrid Air Vehicles (in partnership with the American company Northrop Grumman) won a US army contract for the long endurance multi-intelligence vehicle (LEMV). The LEMV, as long as a rugby field, uses helium for only part of its lift, the remainder coming from its shape which acts like an aircraft wing.
The LEMV is intended for surveillance in places like Afghanistan, but much larger versions are possible and Hybrid Air Vehicles is banking on demand for these. These airships don't need a human crew to operate, and can tolerate being punctured without falling from the sky.
There are even more exotic possibilities. The Swiss Federal Laboratories for Materials Science and Technology built a prototype airship in 2009 that uses artificial muscles to contract one side of the ship then the other to swim through the air like a fish.
It seems like we will be seeing more of these graceful machines in years to come. Perhaps we are on the verge of a new era of airship transport – or perhaps it's just another flight of fancy.
- The Press