Curiosity

What Destroyed the Hindenburg FAQ

posted: 12/06/12

Q: When and where did the Hindenburg crash?

A: The Hindenburg crashed on May 6, 1937, in Lakehurst, N.J. It was the first air disaster ever recorded on film, and it took 36 lives.

Q: How long did it take for the Hindenburg to be destroyed?

A: The ship was destroyed in just 34 seconds.

Q: What was the officially stated cause of the crash at the time?

A: Air-crash investigations in the U.S. and Germany concluded that a spark ignited leaking hydrogen, but they could neither agree on the cause of the spark nor prove the hydrogen leaked. At the time, many were convinced it was sabotage.

Q: How big were the replica Hindenburg airships used by the Curiosity team when recreating the crash?

A: The Curiosity team used 80-foot (24-meter) scale replicas.

Q: How long did it take to build the real Hindenburg?

A: The Hindenburg was built in four and a half years; its construction cost $42 million.

Q: How much material was used in the frame of the Hindenburg?

A: The air-frame alone took 14 miles (22.5 kilometers) of aluminum and 85 miles (137 kilometers) of steel wire. The ship was enclosed by 350,000 square feet (32,516 square meters) of painted linen fabric. In its day, the Hindenburg was the biggest aircraft ever built.

Q: How did the Hindenburg achieve its lift?

A: The Hindenburg derived its lift from 16 air-tight cotton bags containing 7 million cubic feet of hydrogen gas.

Q: Where did the Hindenburg passengers ride?

A: Quarters for the ship's 50 passengers were in the base of the ship.

Q: Was the crash the maiden voyage of the Hindenburg?

A: No, the Hindenburg was a well established craft. Launched in 1936, she flew all over Europe, to Africa and South America, and she was the first airliner to regularly fly to the U.S.

Q: Did other countries also build airships like the Hindenburg?

A: No. By 1937, German airships dominated the skies, because no other nation had mastered the use of hydrogen (between 1918 and 1937, five British, French and American airships were destroyed by fire).

Q: What caused suspicions that the Hindenburg was sabotaged?

A: Just before the disaster, the German Embassy received an anonymous letter warning that "something will happen to the back of the Hindenburg," exactly where the disaster began.

Q: When the Curiosity team tested the theory that the Hindenburg was brought down by a bomb, how did they decide where the explosive should go in the replica?

A: After the original Hindenburg explosion, the testimony of a crewman named Helmut Lau, who saw the first flames burst, placed the explosion in the center of the airship. To test the bomb theory, the Curiosity team wired a miniature explosive between two hydrogen bags.

Q: How much hydrogen gas was used to fill the Curiosity test replica of the Hindenburg?

A: The replica was filled with 8,000 cubic feet of highly flammable hydrogen gas.

Q: Did the test bombing bring down the replicated Hindenburg?

A: The miniature bomb was able to destroy the first Hindenburg model, which told the team that the real Hindenburg could have been brought down the same way.

Q: Was the bomb theory popular in its day?

A: Yes, for a lot of people in 1937, a bombing was the obvious explanation for the destruction of the Hindenburg.

Q: Why did so many people think a bomb brought down the famous airship?

A: At the time, there seemed an obvious suspect: a German-American acrobat named Joseph Spah, who had demanded access to the hold of the ship to feed his dog. He had the acrobatic skills to climb the rigging and plant a bomb. In the minds of the investigators, he was the perfect saboteur. But Spah had no motive. He had no reason to risk his life in such a potentially suicidal mission.

Q: What piece of evidence helped dispel the bomb theory?

A: For at least eight minutes before the disaster, the back of the Hindenburg was dropping. For the Curiosity program's airship historian, Dan Grossman, this fact points to a much more likely cause of the disaster: leaking hydrogen. At the time, the Hindenburg crew tried several times to balance the ship by leaking gas from the front and water ballast from the back, but to no avail. No one has ever proved the cause of the leak.

Q: What are some of the theories for the cause of the hydrogen leak?

A: One theory is that the ship became over-stressed in its final turn, causing a bracing wire to snap, slashing open one of the hydrogen gas bags. Another theory is that a gas valve got stuck open.

Q: How much hydrogen gas leaked from the back of the ship?

A: About 50,000 cubic feet of hydrogen leaked from the back of the ship. But some of it got trapped inside the ship. This created a deadly cocktail of hydrogen and air. All it needed was a spark.

Q: What was the second theory tested by the Curiosity investigative team?

A: The second theory tested by the team was that the thunderstorm in which the Hindenburg landed that day in 1937 gave the leaking hydrogen gas the static spark it needed to ignite and bring down the airship.

Q: What happened when the thunderstorm spark theory was tested?

A: The team recreated the storm situation and the spark's purported location in the next replica Hindenburg. While a fire opened at the top of the ship quickly and the hydrogen burned fast, there was no explosive event such as was seen in the Hindenburg, and in the previous Curiosity bomb-theory test. The fire in the roof failed to match that of the real Hindenburg.

Q: After the bomb theory and hydrogen spark theory, what did the Curiosity team test next?

A: The team tested the theory that it was not the hydrogen that was ignited by the spark but instead the ship's skin that caught fire. The skin was covered with explosively flammable paint. According to an ex-NASA scientist, if the skin ignites, the chemicals produce a super-fuel called "thermite." Curiosity's test of the Incendiary Paint Theory, comparing normal aircraft skin and skin identical to the Hindenburg, however, produced no definitive result.

Q: What was the final theory tested by Curiosity to explain the demise of the Hindenburg?

A: The team's final theory was that "St. Elmo's Fire" -- a mysterious phenomenon seen for centuries, where tall objects in storms seem to produce their own lightning sparks -- triggered an explosion in the heart of the ship.

Q: What was the Curiosity team's final determination for the cause of the Hindenburg crash?

A: Putting its final Hindenburg test model into action, the team determines this sequence of events: As it approached Lakehurst, the airship became electrically charged in the giant thunderstorm; as she made her final turn to land, either a bracing wire snapped or a gas valve stuck open; the crew noticed the tail dropping and realized they were leaking hydrogen; in the back of the airship, the hydrogen mixed with air in the ventilation shafts; outside, the landing crew grabbed the landing ropes, grounding the Hindenburg; flames in the tail ignited the leaking hydrogen; and fire tracked into the belly of the ship, where it hit the source of the hydrogen leak. That was how the Hindenburg was brought down.

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