I learned this today. The Hindenburg airship probably caught fire because of a static electric charge that ignited the highly flammable hydrogen it was filled with.
The Hindenburg was actually called LZ 129 and was one of two giant airships in the Hindenburg class. Its sister ship was called the Graf Zeppelin. They were 245m long and 41m wide. A 747 is 70m long, so that is the length of 3.5 747s. The class was named after the German World War 1 general and president of Germany, Paul von Hindenburg.
The Zeppelin company was started by Ferdinand von Zeppelin, a German general. He was an official observer in the American Civil War and was taken with the idea of hot air balloons. He resigned from the army in 1891 and devoted his time to designing an airship. He couldn’t find success because the frame and the engine were too heavy. By the 1880s, aluminium was starting to be mass produced and Zeppelin heard of aluminium engine parts and an aluminium frame. This adaption allowed his zeppelins to fly and the first successful flight was in 1900.
The Zeppelins were filled with hydrogen gas because it is abundant and has a lot of lift. Hydrogen is much less dense than air and one cubic meter of hydrogen can lift 1.2kg of weight. The same amount of helium can only lift 1.1kg. Plus, helium is far rarer and more expensive. The only available helium in the world was in America and the Americans had banned the sale of it. The only problem with hydrogen is that it is highly flammable.
Up to World War 1, airplanes were in their infancy and what planes did exist could only carry one or two people. The Zeppelin company started to use airships for international travel and they had transported 34,028 passengers by the start of World War 1.
During World War 1, the zeppelins were used to conduct long range bombing raids over Britain. The fear instilled by the site of these giant ships in the sky was probably more effective than the actual bombs they dropped.
The research advantage brought by war helped improve the technology of the airships and they became the most common form of luxury international travel after the war. People without money went by ship and people with money went by Zeppelin.
In the early 1930s, the Zeppelin company became attached to the Nazi party and started to build military airships as well. Zeppelins and other airships were increasing and people began to see it as the future of air travel.
The Hindenburg and the Graf Hindenburg were finished in 1936 and they were used to promote the 1936 Berlin Olympic games. On March 31st, 1936, the Hindenburg set out on its first international flight to Rio de Janeiro. After that, it started flying between Germany and North America. The Hindenburg was an experiment to see if transatlantic airship flight would be profitable and more Zeppelins were planned. A flight from Germany to America would take between 52 and 72 hours, depending on the wind.
The cabin for the passengers was basically a flying hotel and was very luxurious. It wasn’t suspended below the balloon but built into the bottom of it. This is one reason why more people couldn’t escape the ship during the fire.
On May 6th 1937, after a little over one year of flying, the Hindenburg flew into Naval Air Station Lakehurst, New Jersey, United States. There had been a storm and it was still raining. The Hindenburg came in to dock with its mooring mast when it suddenly caught fire. The flames engulfed the whole ship in seconds, and it fell to the ground. Out of the 97 people on board, 13 passengers and 22 crewmen died, most of them burned to death. The images of the airship burning up are some of the most famous photographs of the 20th century.
There is no definite reason why the fire started, although static electricity seems to be the most likely cause.
The skin of the Zeppelin hadn’t been designed to distribute an electric charge evenly and the metal frame allowed a large difference in potential to accumulate between the skin and the frame. On top of this, the Zeppelin had flown through a weather front of high humidity and high electrical charge. When the ship docked and the landing ropes were lowered to the ground, there was no electrical discharge straight away, but the ropes would have been dry and nonconductive. It was still raining lightly and it wouldn’t have taken the ropes long to become wet. When they did, the ropes earthed the Zeppelin’s frame but not its skin. The potential difference between the skin and the frame would have caused a spark, which ignited the hydrogen.
Once the hydrogen was alight, it quickly spread to all of the cells of hydrogen and the whole airship was completely consumed in about 35 seconds.
There is no actual evidence for the static electricity theory, but the Zeppelin company were obviously concerned about it enough that they made changes in their next line of Zeppelins to prevent it happening again. This was never revealed to the public, though, because the Nazi party didn’t want to be associated with a mistake on such a grand scale.
There were more airships built after the Hindenburg, but confidence in Zeppelin travel had been shattered and they would all be destroyed. The Graf Zeppelin, the Hindenburg’s sister ship, was destroyed in 1940. People were willing to pay for luxury travel, but they needed to know that they were safe.
So, the Hindenburg was the world’s largest airship and a source of pride for the Nazi German government. It flew into America through weather conditions that left it charged with electricity. The ropes used to moor it became wet, grounded it and caused a spark that ignited the hydrogen inside it. And this is what I learned today.
Photo By Sam Shere (1905–1982) – Zeppelin-ramp de Hindenburg / Hindenburg zeppelin disaster, Public Domain, https://commons.wikimedia.org/w/index.php?curid=19329337
Sources:
https://www.history.com/this-day-in-history/the-hindenburg-disaster
https://en.wikipedia.org/wiki/Hindenburg_disaster
https://en.wikipedia.org/wiki/Luftschiffbau_Zeppelin
https://en.wikipedia.org/wiki/LZ_129_Hindenburg
https://en.wikipedia.org/wiki/Hindenburg-class_airship
https://en.wikipedia.org/wiki/Ferdinand_von_Zeppelin
https://www.history.com/news/hindenburg-disaster-zeppelin-crash-why