Mention a Zeppelin and what do you think of? The Hindenburg in flames, and perhaps the Goodyear hovering over a football stadium? Led Zeppelin, the great British rock band? This is pretty much all that the term 'Zeppelin' conjures up in the public imagination. But the truth is that the Zeppelin, or Dirigible, has a long and successful history. For years these great airships plied the globe, covering millions of miles ferrying people across the Atlantic and around the world. Then suddenly they disappeared, like wraith-like dinosaurs, not even leaving their bones for us to wonder at.
The simple concept of a gas-filled balloon with a motor attached proved very attractive to the inventors of the late 19th Century, eagerly pursuing their dream of 'man in flight'. They used vast bags of hydrogen 100 feet or more in length to lug the weight of their steam, gas, petrol and electric engines into the air. With the addition of a simple propeller, it was possible to move the bag around. Many of these machines managed trips of up to 20 miles, and one early example famously managed to fly around the Eiffel Tower, but they all shared the same problem; they were just so big and floppy that they could not operate in even the slightest wind.
Most inventors recognised that the balloon would function better if it was cigar-shaped to give at least some semblance of aerodynamic efficiency, and it was also relatively easy to construct the bag in such a way that the pressure of the gas inside maintained the now familiar blimp shape. However, the materials of the day - typically rubberised cloth and cattle intestines - were neither strong nor gas-tight, and leakage and punctures were common. Once the internal pressure dropped, the balloon quickly lost its taut shape and became unmanageable.
It was a former German cavalryman, fascinated by the subject since watching the launch of unpowered observation balloons in the American Civil War, who first clearly realised the need for a rigid steerable frame. Count Ferdinand von Zeppelin built his first airship around an aluminium framework in 1900, and went on to found Delag, the first well-financed air transportation company in the world. In the five-year period before the First World War, Delag airships made some 1,588 flights, carrying 34,228 passengers a total of some 170,000 miles. So successful were his designs that the word Zeppelin became synonymous with powered airships.
Zeppelin continued improving his designs throughout the First World War, building 88 for military use, many of them being used in bombing raids over London and Paris. On the face of it these slow-moving behemoths should have been easy targets for the defensive fighter planes, but they could maintain higher altitudes than any of the aeroplanes then available.
The Golden Age
It was becoming clear that these craft were quite capable of maintaining speeds of around 45mph for thousands of miles without having to land, and since fuel was only needed for propulsion - the gas bag kept the airship aloft - relatively little fuel needed to be carried when compared with heavier-than-air aeroplanes. In the mid-twenties, several attempts were made to explore the north pole using airships. An Italian vessel bearing a team of explorers including Roald Amundsen successfully traversed the pole, but a similar craft several years later perished resulting in eight deaths.
Towards the end of the First World War, British designers were already planning ahead for the day when the safer non-flammable helium gas would become commercially available, and when hostilities were over it was a British airship, the R34, that made the first transatlantic crossing. A larger version, the R38, was built shortly afterwards, but airships continued to suffer from adverse weather conditions and both were destroyed in the same year.
However, construction continued apace, with the monster R100 and R101 each capable of carrying 100 passengers in oceanliner-style comfort, but the latter ship was completely destroyed by a fire in a storm over France on its way to India, with the loss of 46 passengers and crew. The R100 was immediately decommissioned and the British government abandoned the development of dirigibles.
The Return of the Zeppelin
Meanwhile, Germany had been permitted to return to civilian flying, and the Zeppelin company, now headed by Zeppelin's successor Hugo Eckener, began planning its own transatlantic passenger ship. The result was the 772-foot Graf Zeppelin, which, with Eckener at the helm, circumnavigated the globe in 21 days, and went on to cover over a million miles in its nine years of service.
Eckener's next project, the 804-foot machine that came to be known as the Hindenburg, was initially another success, ferrying 1,002 people on ten round trips between Germany and the United States in its first year, but by then Eckener had fallen out of favour with Hitler's government and had been relieved of his command. The Americans still refused to give Germany access to the new safer helium gas, and the Hindenburg was completely destroyed at its New Jersey landing field in a massive hydrogen explosion, causing the deaths of 36 people. The wave of bad publicity that followed, combined with the imminent inauguration of the first transatlantic airliner, and the outbreak of war that resulted in the complete destruction of the Zeppelin airship works by Allied bombs, effectively finished the airship as a commercial vehicle. It is interesting to speculate on the course of aviation history if the war had not spurred on the development of aeroplanes as faster and more efficient killing machines.
The Present and the Future
Today, the only dirigibles that you are likely to see are the Goodyear and Coca Cola airships, maintained for their advertising exposure and occasionally used as camera platforms at sporting events. These ships are, however, anachronisms, and without the forces of marketing behind them they would long ago have been grounded.
However, the airship concept is still sound. There is something seductive about an aircraft that requires very little fuel and can carry heavy loads for long distances, and every ten years or so someone announces that they are working on a new airship. Usually these designs sink without trace due to lack of financial backing, but with the advent of newer lightweight materials and the development of modern navigational and computer control systems, manufacturers are once more showing an interest.
There are over a dozen airship manufacturing companies in the world, scattered throughout Europe and America. Many exist merely as a forum, or are only at the design stage, but some are actively marketing machines that they have built. None have so far recreated large manned Zeppelin-style craft, but radio-controlled dirigibles are proving useful for surveillance and camera work, and many people are showing interest in the airship as a base for eco-friendly tourism, for instance on safari or desert tours where the terrain is too uncomfortable or delicate for ground-based tourism.
The Hamilton Airship Company (THAC) are perhaps the most advanced of these modern designers. Their airship has a number of clever innovations that should allow it to overcome the traditional limitations of the Zeppelin. The rigid frame is constructed from a flexible alloy, so that in adverse weather conditions the skeleton will flex rather than shatter, and the hollow spine can be pumped full of pressurised air to increase the weight and therefore control the buoyancy without having to dump ballast all over the landscape. THAC have also done away with the need for huge mooring masts, as their airship contains an internal hydraulic mast that gives it the flexibility of a conventional aircraft's undercarriage.
The company has also had to set up a pilot training school, because after all the last qualified airship captain flew in World War II...
Perhaps with the new millennium and our improved technology and greater concern for the environment, we will once more be seeing these gentle giants of the skies.