ABC Science

Hindenburg & Hydrogen

One of the most famous images of the 20th Century was that of the giant German airship Hindenurg engulfed in flames. The explosion was blamed on hydrogen gas but Dr Karl reckons it can't be so...

By Karl S. Kruszelnicki

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Paragraph 10 / Back in the middle 1930s, if you were wealthy enough to fly across the Atlantic Ocean, there were two choices - noisy, small and cramped aeroplanes, or quiet and spacious airships that got their lift from huge bladders filled with hydrogen gas. Back then, it was still an even bet as to which technology would win in the long run - the faster and noisy aeroplanes, or the slower and more relaxed Lighter-Than-Air airships.
The answer was settled in favour of the aeroplanes in 1937, when the enormous Nazi hydrogen-filled airship, the Hindenburg, slowly maneuvered in to dock at a 50-metre high mast at the Lakehurst Air Base, in New Jersey. This was its 21st crossing of the Atlantic Ocean. Suddenly, there was a spark on the Hindenberg, and then flames. Newsreel film crews captured the sudden disaster as the Hindenburg burst into enormous plumes of red-yellow flames, and collapsed to the ground. Over thirty of the 97 people on board died. The disaster was blamed on the extreme flammability of the hydrogen lifting gas that filled most of the airship.
This bad reputation of hydrogen still bothers car manufacturers today, as they explore the use of hydrogen as a safe, non-polluting alternative to fossil fuels for powering cars. But it turns out that the extreme flammability of hydrogen is a myth conception.
The Hindenburg was the largest aircraft ever to fly - longer than three football fields (about 250 metres long). It was powered by four enormous …diesel engines that spun 6-metre wooden propellers. It cruised at 125 kph (faster than ocean liners and trains), and when fully loaded with fuel, had a range of some 16,000 km. It was opulently and almost decadently luxurious - each of the 50 cabins had both a shower and a bath, as well as electric lights and a telephone. The clubroom had an aluminium piano. The public rooms were large and decorated in the style of luxury ship - and the windows could be opened. It might be a little slower than the aeroplanes of the day - but it was a lot more comfortable.
The Hindenburg was painted with silvery powdered aluminium, to better show off the giant Nazi swastikas on the tail section. When it flew over cities, the on-board loudspeakers broadcast Nazi propaganda announcements, and the crew dropped thousands of small Nazi flags for the school children below. This is not surprising, because the Nazi Minister of Propaganda funded the Hindenburg.
At that time, the US government controlled the only significant supplies of helium (a non-flammable lifting gas), and refused to supply it to the Nazi government. So the Hindenburg had to use flammable hydrogen.
As the Hindenburg came in to Lakehurst on May 6, 1937, there was a storm brewing, and so there was much static electricity in the air - which charged up the aircraft. When the crew dropped the mooring ropes down to the ground, the static electricity was earthed, which set off sparks on the Hindenburg.
The Hindenburg was covered with cotton fabric, that had to be waterproof. So it had been swabbed with cellulose acetate (which happened to be very inflammable) that was then covered with aluminium powder (which is used as rocket fuel to propel the Space Shuttle into orbit). Indeed, the aluminium powder was in tiny flakes, which made them very susceptible to sparking. It was inevitable that a charged atmosphere would ignite the flammable skin.
In all of this, the hydrogen was innocent. In the terrible disaster, the Hindenburg burnt with a red flame. But hydrogen burns with an almost invisible bluish flame. In the Hindenburg disaster, as soon as the hydrogen bladders were opened by the flames, the hydrogen inside would have escaped up and away from the burning airship - and it would not have not contributed to the ensuing fire. The hydrogen was totally innocent. In fact, in 1935, a helium-filled airship with an acetate-aluminium skin burned near Point Sur in California with equal ferocity. The Hindenberg disaster was not caused by the hydrogen.
The lesson is obvious - the next time you build an airship, don't paint the inflammable acetate skin with aluminium rocket fuel.

Questions:

1. What do the following words mean?

a.Flammable

b.Opulent

c.Decadent

d.Mooring

2. Back in the 1930s what was the 2 ways you could cross the Pacific Ocean by air? (paragraph 1)

3. What were the conditions like for a passenger on the Hindenburg? (paragraph 4)

4. What happened to the Hindenburg in 1937? What element was blamed for the disaster? (paragraph 2)

5. Why is that still a problem today? (paragraph 3)

6. They were wrong. What 2 clues led scientists to know that they were wrong? (paragraph 9)

7. What actually burned on the Hindenburg? (paragraph 8)

8. What other gas could have been used? Why did the US not allow it to be used at that time? (paragraph 6)

9. In your own words, what should you not do if you own an airship? (paragraph 10)

Published 26 February 2004