Airship

• 1. Introduction

  ›

  Airships were the first aircraft capable of controlled powered flight. Before the aeroplane conquered the skies, massive hydrogen-filled giants crossed oceans, bombed cities, and carried passengers in cabins fitted with private berths and dining rooms. Then, on the 6th of May 1937, a craft named Hindenburg approached its mooring mast at Lakehurst, New Jersey, burst into flames before a watching crowd, and in minutes reduced the golden age of the airship to ash and newsreel footage.

  But that disaster was not the whole story. It was not even the beginning. The airship's journey stretches back to a Jesuit priest in 1670 who dreamed of copper spheres evacuated of air, through a Brazilian inventor circling the Eiffel Tower in 1901, through two world wars in which lighter-than-air craft served as bombers, submarine hunters, and airborne aircraft carriers. How did a machine so beautiful and so dangerous come to define an era? And what has become of it since?

• 2. How an Airship Flies

  ›

  Lift in an airship comes not from speed or wing shape but from the simple fact that certain gases weigh less than air. The gas inside the envelope displaces heavier air around it, and that difference in density pushes the craft upward, in much the same way a bubble rises through water.

  Hydrogen offers the strongest lift at 1.1 kilograms per cubic meter and is easy to obtain, but it will ignite and can detonate when mixed with air. Helium lifts slightly less at 1.02 kilograms per cubic meter, cannot burn, and was for years available only in the United States, where significant deposits were first discovered. Most airships built since the 1960s have used helium, though some have used hot air.

  The shape of an airship depends on how it is built. Non-rigid types, called blimps, hold their form through nothing more than the pressure of the gas inside. Semi-rigid designs add a supporting keel running along the bottom of the envelope. Rigid airships go further still, wrapping an outer structural framework around internal gas cells so the hull keeps its shape regardless of how much gas remains inside. It was the rigid type that Count Ferdinand von Zeppelin championed, and the firm he founded, Luftschiffbau Zeppelin, built the vast majority of rigid airships ever flown.

  Pilots control altitude by managing small internal air bags called ballonets. Inflating a ballonet reduces the volume available for lifting gas, increasing the craft's overall density and causing it to descend. Deflating it does the reverse. By working fore and aft ballonets independently, a crew can also trim the pitch of the nose. Fins on the tail section maintain stability, while movable rudders steer the craft left and right.

• 3. Pioneers and Dreamers

  ›

  Francesco Lana de Terzi, a Jesuit priest sometimes called the Father of Aeronautics, published in 1670 a description of an aerial ship lifted by four copper spheres from which all air had been removed. The principle was sound, but the math was not: air pressure would crush any sphere thin enough to be light.

  Practical progress came slowly. In 1709, the Brazilian-Portuguese priest Bartolomeu de Gusmao demonstrated a small hot air balloon before King John V of Portugal, the craft rising 95 meters on its second attempt. In 1784, Jean-Pierre Blanchard fitted a hand-powered propeller to a balloon, the first recorded means of propulsion carried aloft. A year later he crossed the English Channel using flapping wings and a birdlike tail for steering.

  The decisive leap arrived in 1852, when Henri Giffard flew 27 kilometers in a steam-powered airship, becoming the first person to make an engine-powered flight. In 1884, Charles Renard and Arthur Constantin Krebs flew La France, a craft 170 feet long powered by an 8.5 horsepower electric motor and a 435 kilogram battery. La France covered 8 kilometers in 23 minutes and was the first airship to land at the spot where it took off.

  Alberto Santos-Dumont, a wealthy young Brazilian living in France, brought airships to public attention in a way no engineer had managed before. On the 19th of October 1901, he flew his airship Number 6 from the Parc Saint Cloud to the Eiffel Tower and back in under thirty minutes, winning the Deutsch de la Meurthe prize of 100,000 francs. His small, nimble craft inspired a generation of designers. Across the Atlantic, inventors such as Walter Wellman and Melvin Vaniman aimed higher still, attempting polar flights in 1907 and 1909 and transatlantic crossings in 1910 and 1912. The skies were filling with ambition.

• 4. War in the Air

  ›

  Italian forces became the first to use dirigibles in combat, flying the first bombing mission on the 10th of March 1912 during the Italo-Turkish War. By 1915, German zeppelins were raiding England, and the raids peaked in 1916. The Germans believed they had found a weapon that could reach across the North Sea and strike at Britain itself.

  The reality was grimmer. Navigation, target selection and bomb-aiming proved difficult even in good conditions, and cloud cover made accuracy worse. The physical damage done across all airship raids was insignificant, and the deaths caused amounted to a few hundred. Yet the psychological effect was real enough to pull substantial British resources into air defense.

  At first the zeppelins were nearly impossible to attack. Because the pressure inside their envelopes barely exceeded outside air pressure, bullet holes had little effect. That changed in 1916 when incendiary and explosive ammunition was introduced, turning flammable hydrogen into a fatal vulnerability. Several were shot down in flames.

  The Royal Navy found a different use for airships entirely. Beginning in February 1915, the British developed the SS class of blimp for coastal patrol, hunting submarines and clearing mines. The North Sea class, the largest non-rigid type in British service, carried a crew of ten, held 10,200 cubic meters of gas, and could stay aloft for 24 hours. By war's end Britain had operated over 200 non-rigid airships and was the world leader in the type.

  Rigid airships saw one last flash of offensive action on the 19th of July 1918, when seven Sopwith 2F.1 Camels launched from a ship and struck the airship base at Tonder, destroying zeppelins L 54 and L 60. It was the first successful carrier-based air strike in history.

• 5. The Golden Age and Its Collapse

  ›

  On the 2nd of July 1919, the British airship R34 began the first crossing of the Atlantic by a passenger aircraft. It landed at Mineola, Long Island on the 6th of July after 108 hours in the air. The return crossing took 75 hours. Despite the feat, enthusiasm for further British airship development dissolved rapidly.

  Germany moved boldest. The Graf Zeppelin, LZ 127, flew over 1,600,000 kilometers, including the first circumnavigation of the globe by airship, without a single passenger injury. It burned blau gas, similar to propane, as fuel; since blau gas was as dense as air, burning it did not lighten the ship and force the crew to valve off expensive hydrogen. By the mid-1930s the Zeppelin company was running a passenger service between Frankfurt and Recife in Brazil, taking 68 hours, and the operation was nearly profitable.

  The Hindenburg, LZ 129, completed a successful 1936 season carrying passengers between Lakehurst and Germany. On the 6th of May 1937, approaching the mooring mast at Lakehurst minutes before landing, it burst into flames. Of the 97 people aboard, 35 died: 13 passengers, 22 aircrew, and one American ground crewman. The disaster was filmed, witnessed by a large crowd, and broadcast through a radio reporter's grief-stricken commentary. Theater audiences across the world saw and heard it in newsreels.

  The day after the disaster, the Graf Zeppelin landed safely in Germany from Brazil. It was the last international passenger airship flight. Hindenburg's identical sister ship, Graf Zeppelin II, could not carry commercial passengers without helium, which the United States refused to sell to Germany. Both craft were scrapped in April 1940.

• 6. Submarine Hunters

  ›

  When Japan attacked Pearl Harbor on the 7th of December 1941, the U.S. Navy had exactly ten non-rigid airships, most of them patrol or training ships built in 1938. Within weeks they were pressed into combat against German and Japanese submarines sinking American shipping within visible distance of the coast.

  The Navy formed the ZP-12 patrol unit on the 2nd of January 1942, basing it at Lakehurst with four K-class airships. Production followed quickly: between 1942 and 1945, the Goodyear factory in Akron, Ohio built 154 airships for the Navy. In those same years, approximately 1,400 airship pilots and 3,000 support crew were trained, and naval airship personnel grew from 430 to 12,400.

  The blimps proved excellent at driving submarines underwater, where the submarines' limited speed and range prevented them from pursuing convoys. During the war, 532 ships traveling without blimp escort were sunk near the American coast. Of the more than 89,000 ships in convoys under blimp protection, only one was sunk by a submarine: the tanker Persephone.

  Only one American airship was destroyed by a U-boat. On the night of the 18th and the 19th of July 1943, K-74 located a surfaced German submarine near Florida using radar and made its attack run, but the depth charges failed to release and the U-boat's fire damaged K-74 badly. The crew survived the forced water landing; one crewman, Aviation Machinist's Mate Second Class Isadore Stessel, later died from a shark attack. The U-boat was itself damaged and was finally sunk on the 24th of August 1943 by a British Vickers Wellington near Vigo, Spain.

  In 1944-45, a squadron of eight K-class blimps flew from North Carolina to Naval Air Station Port Lyautey in French Morocco, completing the first transatlantic crossing by non-rigid airships on the 1st of June 1944. Their mission was to establish a round-the-clock magnetic anomaly detection barrier at the Strait of Gibraltar, where German U-boats moved through shallow water. The same squadron also escorted the convoy carrying President Franklin D. Roosevelt and Prime Minister Winston Churchill to the Yalta Conference in 1945.

• 7. Airships After the Golden Age

  ›

  Non-rigid airships outlasted the rigid kind. In May 2006 the U.S. Navy flew airships again after a hiatus of nearly 44 years, operating a single American Blimp Company A-170 for crew training and research at Lakehurst, the original center of American lighter-than-air operations.

  In the 1990s, the successor to the original Zeppelin company in Friedrichshafen, Zeppelin Luftschifftechnik GmbH, built a new model: the Zeppelin NT. Its maiden flight was on the 18th of September 1997. Smaller than the great prewar ships and technically a semi-rigid, the NT offered higher speed and better maneuverability than common blimps. In June 2004 one was sold to the Japanese company Nippon Airship Corporation for tourism and advertising around Tokyo; it was given a role at the 2005 Expo in Aichi as well. When Russian authorities denied overflight permission for the delivery flight, the airship was dismantled and shipped by sea instead.

  De Beers, the diamond mining company, launched an airship exploration program over the Kalahari Desert in November 2005, using a Zeppelin NT fitted with a Bell Geospace gravity gradiometer to scan for kimberlite pipes, the low-density rock formations that indicate potential diamond deposits. The very stable, low-vibration NT platform was well suited to the precision instrument work.

  Heavy-lift cargo airships have attracted recurring interest. Between 1996 and 2002 the German CargoLifter project planned a hybrid airship larger than the Hindenburg. Around 2000, CargoLifter AG built the world's largest self-supporting hall, measuring 360 meters long, 210 meters wide and 107 meters high, about 60 kilometers south of Berlin. The project stopped for financial reasons in May 2002 and the company filed for bankruptcy. The vast hangar was later converted into the Tropical Islands Resort, a large indoor water park and leisure facility that still operates today, standing as one of the more unusual monuments to an idea that never quite reached the sky.