The Hindenburg and Hydrogen: Nonsense from Dr. Karl Kruszelnicki

by Dan Grossman on August 26, 2009

Dr. Karl Kruszelnicki (CreativeCommons.org license, courtesy Enoch Lau)

Dr. Karl Kruszelnicki (CreativeCommons.org license, courtesy Enoch Lau)

Dr Karl Kruszelnicki is an Australian TV scientist who wrote about the Hindenburg in his book Great Mythconceptions: The Science Behind the Myths.

Dr. Karl’s conclusion regarding the Hindenburg disaster is that the “hydrogen was totally innocent” and “would not have not contributed to the ensuing fire.”  According to Dr. Karl, the lesson of the Hindenburg tragedy is “the next time you build an airship, don’t paint the inflammable acetate skin with aluminium rocket fuel.”

Dr. Karl’s commentary about the cause of the Hindenburg disaster is frequently cited on the internet.

But just about every historical and scientific fact in Dr Karl’s commentary is wrong.

At the end of this post is a speculation about why Dr. Karl might publish such nonsense.

Dr. Karl’s Complete Hindenburg Article and Rebuttal

The following is the complete text of Dr. Karl’s article, which is also available here.

(Dr. Karl’s article is reprinted in its entirety in the interest of clarity and to be fair to Dr. Karl, to make clear that none of his words are being presented out of context.)

After each quotation from Dr. Karl (in plain text), the truth is in blue italics.

*****************************************

HINDENBURG AND HYDROGEN, by Karl S. Kruszelnicki

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.

THE TRUTH:  Transatlantic airplanes and airships never operated at the same time; the first transatlantic airline service by airplane did not start until 1939, more than two years after airship service ended with the Hindenburg disaster, so passengers never had a choice between the two.

(And when airline service finally did begin with the Pan Am clippers, the planes were certainly not small and cramped.)

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.

THE TRUTH: Hindenburg’s last flight was actually its 37th crossing of the Atlantic, rather than its 21st, and the Lakehurst mast was about half the height cited by Dr. Karl; very small mistakes, to be sure, but indicative of Dr. Karl’s reliance on untrustworthy source material, as explained in greater detail below.

Suddenly, there was a spark on the Hindenburg, 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 mythconception.

THE TRUTH: Regardless of what caused the Hindenburg disaster, hydrogen is a highly flammable gas, and OSHA requires warning placards when it is in use.

hydrogen-warning
Hydrogen Warning Placard

The Hindenburg was the largest aircraft ever to fly – longer than three football fields (about 250 metres long). It was powered by four enormous 1,200 HP V-16 Mercedes-Benz 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 TRUTH: Hindenburg passenger cabins did not have individual showers and baths, or even telephones; the ship had only one shower which was shared by all passengers, since the weight of individual bathrooms (and the water they would have required) would have been well beyond the lifting ability of the lighter-than-air Hindenburg.

While obviously not related to the cause of the disaster, and a relatively trivial mistake, Dr. Karl’s exaggerations about the passenger cabins demonstrate his extreme carelessness (and possible political bias) in choosing source materials.  No reliable account of the Hindenburg, of which there are many, make these claims regarding the Hindenburg’s passenger accommodation; on the other hand, Dr. Karl’s article is virtually identical with the description of Hindenburg in the book The Philosopher Mechanic by Roy McAlister.  McAlister is not an aviation historian, however; he is a hydrogen advocate associated with the American Hydrogen Association, who has himself distorted the facts of the Hindenburg disaster to suit his agenda.

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.

THE TRUTH: The Hindenburg was not painted silver “to better show of the Nazi swastikas,” and there is no reliable source from which Dr. Karl could have obtained that information.

In fact, the Hindenburg was silver-colored to reduce the heating effects of the sun, which can cause an airship’s gas cells to expand and release their gas; American and British dirigibles used the same technique, and German airships, including the famous Graf Zeppelin, had been coated with reflective aluminum powder for many years before the Nazis took power in Germany.  Painting airships silver had nothing to do with swastikas.

This incorrect information, which Dr. Karl chose to pass along to the readers who trust him, as well as the false information in the following sentences, can also be found, almost word-for-word, in the writings of hydrogen advocate Roy McAlister.

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.

THE TRUTH: The Hindenburg did not routinely broadcast propaganda announcements or drop small Nazi flags; those activities occurred during two or three specially-arranged propaganda flights, but were not routine (the ship made over 60 flights during its career) and certainly did not take place whenever the ship “flew over cities.”

This is not surprising, because the Nazi Minister of Propaganda funded the Hindenburg.

THE TRUTH: The German Air Ministry supplied the vast majority of the funding, nine million Reich Marks, to build the Hindenburg; the Nazi Propaganda Ministry provided just two million Reich Marks.

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.

THE TRUTH: The American restriction against selling helium to other countries was imposed under the Helium Control Act of 1927 which was enacted six years before Hitler took power in Germany in 1933, and was obviously unrelated to the Nazi regime.

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).

THE TRUTH: Not only is Cellulose acetate not “very inflammable,” it is arguably not flammable at all.  Canvas doped with cellulose acetate butyrate (used on the Hindenburg) is combustible, but nonflammable; in other words, it will burn if held in a flame (and therefore “combustible”) but tends to self-extinguish when removed from heat (and therefore “nonflammable”).  In fact, Cellulose acetate was specifically chosen for Hindenburg’s doping solution precisely because of its low flammability.  (See Duggan, John; LZ-129 Hindenburg: The Complete Story. 2002.  p. 178 et. seq.)

THE TRUTH: Dr. Karl states that aluminum powder “is used as rocket fuel to propel the Space Shuttle into orbit.”  In fact, aluminum powder is just one component of the Space Shuttle’s rocket fuel, and makes up only 16% of the mixture.  Aluminum powder is not, by itself, any form of rocket fuel.  Dr. Karl’s frequent comparison of the Hindenburg’s covering to “rocket fuel” is not simply wrong, but probably intentionally disingenuous, since as a scientist Dr. Karl surely knows better.

Perhaps the best evidence that Hindenburg’s covering was not especially flammable are the photographs and films of the disaster, showing how slowly the covering burned; in fact, some sections of the Hindenburg’s covering never burned at all [see photo].

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.

THE TRUTH: The aluminum powder was suspended in the doping solution, and the flakes were not loose, but encapsulated by the dope. Many other airships, including the dirigibles of the United States Navy, used a similar doping solution (with aluminum powder flakes), and none had its covering ignited when operating in a charged atmosphere.  In fact, the Hindenburg itself passed through electrically-charged conditions many times during its previous 62 flights, and its covering did not catch fire, so ignition of the covering in a charged atmosphere was certainly not “inevitable.”

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.

THE TRUTH: Hydrogen does burn with an invisible bluish flame, as Dr. Karl states, but that is true only when hydrogen is the only substance burning.  In the crash of the Hindenburg, many substances burned along with the hydrogen, including miles of steel wire and aluminum girders, the fabric hull covering, remaining supplies of diesel fuel, and even tables and chairs.  Dr. Karl is sufficiently educated as a scientist to understand that these items themselves emitted light and color as they burned, and that they also acted as a mantle, glowing in the heat of the burning hydrogen.

Dr. Karl book excerpt
Illustration from Dr. Karl’s book, filled with erroneous or misleading information. The roof of the passenger compartment was not hermetically sealed; cellulose acetate is not very flammable; aluminum powder by itself is not used as rocket fuel; and hydrogen does not burn with an almost invisible bluish flame when it is consuming miles of steel wire and aluminum girders. (click to enlarge)

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 TRUTH: The idea that millions of cubic feet of hydrogen could burn without “contributing to the ensuing fire” is just silly, and is contradicted by the photographs and films of the Hindenburg disaster.

The hydrogen was totally innocent.

THE TRUTH: The Hindenburg’s hydrogen was certainly not “innocent” with regard to the deaths and injuries suffered by the passengers, crew, and ground personnel.

In fact, in 1935, a helium-filled airship with an acetate-aluminium skin burned near Point Sur in California with equal ferocity.

THE TRUTH: Dr. Karl seems to be referring to the crash of the USS Macon, which did not “burn near Point Sur in California,” but rather crashed into the sea following structural failure.  Gasoline and other flammable materials caught fire after (and as a result of) the crash into the ocean, but the helium-inflated Macon did not “burn with equal ferocity” as the hydrogen-filled Hindenburg, and only two of the 83 men on the USS Macon died in the accident.

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.

THE TRUTH: Some of the covering of the Hindenburg (“painted with rocket fuel,” according to Dr. Karl) which never burned at all during the fire:

Some of the "rocket fuel" coated covering of the Hindenburg which never burned during the fire.
Covering of the Hindenburg which never burned during the fire.

Why would Dr. Karl Publish such Nonsense?  A Speculation:

It might be surprising that a scientist like Dr. Karl would publish such nonsense, especially since many of his books attempt to debunk scientific myths and misconceptions. But his motivation may become less mysterious when one learns that Dr. Karl is also an advocate for hydrogen-powered cars and hydrogen as an alternative source of energy.

Much of the text of Dr. Karl’s article is virtually identical with the description of Hindenburg disaster offered by Roy McAlister in his book The Philosopher Mechanic.  McAlister is not an aviation historian, however; he is a hydrogen advocate associated with the American Hydrogen Association.   Hydrogen advocates have been misleading the public about the Hindenburg disaster for years, in the bizarre belief that they must exonerate hydrogen from blame in the Hindenburg tragedy (whatever the facts) in order to sell hydrogen to the public as an alternative fuel. Of course, their logic is flawed: Theoretically, hydrogen could simultaneously be a wonderful alternative fuel and a terrible lifting gas for passenger airships; there is no necessary contradiction between the two. Many substances which are ideal for one application are hazardous in another, and hydrogen advocates who cannot grasp this obvious principle, and instead spread unscientific myths about the Hindenburg, just raise questions about their own credibility and analytic abilities. After all, many people support solar energy, but they don’t feel the need to claim that sunlight doesn’t cause skin cancer.

Dr. Karl claims that the lesson of the Hindenburg is not to paint zeppelins with rocket fuel, but perhaps the real lesson is not to mislead people who look to you for scientific information, in the interest of political advocacy… however noble the cause.

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