Floating on Gas
An airship floats the way a cork floats in water. It uses a lifting gas that is less dense than the air around it. Unlike a simple balloon, it has its own engines and can steer.
Early airships used hydrogen. It gives the most lift and is cheap and easy to find, but it burns very easily. Helium cannot burn at all, but it lifts a little less and is rare and costly. Large amounts were first found in the United States, and for a while airships could only get helium in North America. Most airships built since the 1960s use helium, and a few use hot air.
Pilots control height with a clever trick. Inside the envelope, the big outer skin, sits an air bag called a ballonet. Pump air in and the airship loses lift and sinks. Let air out and it rises.
Steam, Muscle and a Lap Around the Eiffel Tower
Airships were the first aircraft that could make controlled, powered flights. In 1852, Henri Giffard became the first person to make an engine-powered flight, traveling 27 kilometers in a steam-powered airship. Inventors tried all sorts of power. One French airship from 1872 had a propeller turned by eight men. In 1883, Gaston Tissandier made the first electric-powered flight.
In 1884, the French Army airship La France made the first airship flight that landed back where it took off. It covered 8 kilometers in 23 minutes, using an electric motor and a heavy battery.
Then came the show-offs. On 19 October 1901, the Brazilian flyer Alberto Santos-Dumont flew from Saint-Cloud, around the Eiffel Tower and back in under thirty minutes. He won a prize of 100,000 francs. In Britain, Stanley Spencer paid for the country's first airship by selling advertising for baby food on its sides.
The Zeppelin Golden Age
Count Ferdinand von Zeppelin flew his first rigid airship, the LZ1, in July 1900. His airships had a frame of lattice girders covered with fabric, with separate gas cells inside. They became so famous that big rigid airships are still called zeppelins.
Records fell fast. In 1919, the British R34 made the first Atlantic crossing by a passenger aircraft, spending 108 hours in the air. In 1926, the airship Norge became the first aircraft to fly over the North Pole.
The star was the Graf Zeppelin. It flew more than 1.6 million kilometers, including the first trip around the world by airship, without a single passenger injury. Zeppelins of the 1930s offered private cabins, observation decks and dining rooms, like ocean liners, but they were faster. The catch was that the crew often outnumbered the passengers, and landing needed large ground teams.
Flying Aircraft Carriers
Airships got even wilder in the 1930s. The US Navy tested them as airborne aircraft carriers. The USS Akron and USS Macon, the largest airships in the world at the time, each carried four small fighter planes in a hangar inside. There was room for a fifth on a hanging trapeze. The idea had mixed results, and both ships were later lost in accidents.
Helium was precious back then. When the USS Shenandoah first flew in 1923, it was the first airship filled with helium, and it held most of the world's supply. When a second Navy airship arrived, the two had to take turns using the limited gas.
The golden age of giant passenger airships ended in 1937, when the hydrogen-filled Hindenburg burst into flames while landing in New Jersey. By then, airplanes were already overtaking airships in what they could do.
Diamonds, a Tropical Resort and Venus
Airships never fully disappeared. Since the 1960s, helium airships have been used for advertising, tourism, camera work and surveys, wherever hovering matters more than speed. A new generation, the Zeppelin NT, first flew in 1997. In 2005, the diamond company De Beers used one over the Kalahari Desert, scanning the ground for rock formations called kimberlite pipes to find possible diamond mines.
Other dreams were enormous. Around 2000, the German company CargoLifter built the world's largest self-supporting hall south of Berlin, meant for a giant cargo airship. The project stopped in 2002, and the huge hangar later became the Tropical Islands Resort.
The future may be stranger still. NASA has proposed crewed airship missions to the atmosphere of Venus. At a certain height above that planet, the air pressure matches Earth's. And airships need less energy than other aircraft to stay in the air.
