The heyday of airships, marked by majestic giants such as the LZ-129 "Hindenburg" and the LZ-127 "Graf Zeppelin", was closely linked to the use of hydrogen as a filling gas. But why was hydrogen chosen instead of the safer helium? This question takes a look at the technology and political circumstances of the time.
Some startups see the future of short-haul flights in the use of airships. With one exception, which aims to put a freighter in the air, all modern concepts rely on helium as a filling gas. There is a good reason for this, because a look into the past shows that hydrogen is playing with fire. The D-LZ129 "Hindenburg" is still the most famous airship of all time, not only because of its enormous size, but also because of the Lakehurst tragedy.
This could have been avoided in any case if the noble gas helium had been used instead of combustible hydrogen. That was also planned, because the Hindenburg was designed accordingly by Luftschiffbau Zeppelin. However, the coveted helium, which was only available to the USA in the required quantities at the time, was not available. So hydrogen was used again and since it is lighter than helium, the capacity could also be increased.
It is by no means the case that the Deutsche Zeppelin Reederei, a joint venture between the German Reich, Lufthansa and Luftschiffbau Zeppelin, did not know that hydrogen was dangerous as a lifting gas. The now largely forgotten accident of the British airship R101 on October 4, 1930 prompted Hugo Eckener, managing director of Luftschiffbau Zeppelin, to ask his then partner Goodyear in the USA to arrange a delivery of helium. This was no longer intended for the D-LZ127, but the D-LZ129 was to be filled with it. The noble gas was also planned for the D-LZ130 "Graf Zeppelin II". It never happened; all Zeppelins of the heyday were filled with hydrogen without exception.
Why hydrogen instead of helium?

In the heyday of airships, particularly in the 1920s and 1930s, helium was known as a safer filling gas, but it was also more expensive and difficult to obtain. The United States was the main producer of helium at the time, and due to political and economic considerations, most airship manufacturers, particularly the German Zeppelin factories, chose the more readily available hydrogen.
All German airships were filled with hydrogen, regardless of the manufacturer. In the first few years after the first flight of the D-LZ1 there were various producers, but gradually only Luftschiffbau Zeppelin remained in the field of rigid airships. Since their first flight, their airships have repeatedly had catastrophic accidents in which hydrogen has proven to be problematic. However, in the golden era, i.e. in the interwar period, regular service had an impeccable safety record even after it was spun off into the DZR. In contrast to other countries, there has not been a single hydrogen accident and this has created a mixture of trust and arrogance.
In Germany it was believed that hydrogen was absolutely safe as long as you knew how to use it. The British R101 accident was viewed - apart from Hugo Eckener - as being of the opinion that something like this could never have happened with a German Zeppelin. This was a crux that meant that Eckener, who absolutely wanted helium for the large airships LZ-129 and LZ-130, did not necessarily receive support from the DZR and even within Luftschiffbau Zeppelin. Too expensive, too complicated and, in general, you can carry more passengers with hydrogen as a carrier gas.
The D-LZ127 "Graf Zeppelin" was the most successful airship of all time. No other rigid airship had such a long service life that was reliable without any notable incidents. This Zeppelin was in transatlantic service for a comparatively long time and even circumnavigated the globe, which was an absolute world sensation at the time. The LZ127 was filled with hydrogen and not helium. The great success of this airship also meant that the German authorities had greater confidence in the flammable lifting gas than ever before.
“Graf Zeppelin” – Most successful airship of all time

It's a puzzling but true story: the D-LZ127 was actually only built as a test airship. It even has an extremely unfavourable diameter. This is because the hangar was simply not big enough. This "misconstruction" made it a little more complicated to control, but that was it, because its years of success speak for themselves.
It should also be noted that there is a significant difference in a direct comparison between the D-LZ127 and the LZ-129/130: On the Graf Zeppelin, the passengers were accommodated in the gondola beneath the hull. The impressive "cigar", as airships were also called at the time, was only accessible to crew members. It was different with the Hindenburg and its sister ship, the Graf Zeppelin II: the passengers were accommodated in the hull and the gondola only housed the radio room and the bridge. The D-LZ127 had an enormous number of comfortable facilities that were not found on its successors. Rather, it was very cramped and extremely spartan, although an attempt was made to offer a little bit of luxury.
However, Hugo Eckener was of the opinion that the successor to the Graf Zeppelin would have to be filled with helium because he saw the fact that the actual transport takes place in the fuselage as a safety risk. The manager enjoyed a very high reputation in the United States of America and maintained close contacts with the Goodyear Company. With their help, he tried to get the coveted helium. Even the transport containers have already been brought to the USA from Germany. Everything looked like it was going to work.
But Hugo Eckener, who was not at all inclined to National Socialism but was only spared because of his popularity, did not take the new rulers in Germany into account. The fact that neighbors were increasingly threatened and massive armament was being pursued led the USA to decide not to supply helium. It was feared that the civilian airship could only be a pretext for military use. In fact: During the First World War, hydrogen-filled zeppelins caused fear, horror and many dead people in London. It is very unlikely that airships could have played a similar role in World War II, as aircraft were evolving rapidly and Zeppelins would have been a very easy target. Filled with hydrogen, especially.
Nevertheless: The USA has decided that no hydrogen will be delivered to Nazi Germany. But in Germany they didn't want to let this get them down, because Eckener's critics literally laughed up their sleeves and also saw themselves confirmed. Now the time had come: the Hindenburg was converted and filled with flammable hydrogen. People knew exactly how high a security risk this was. At least outside of Germany, because the airshipmen at the time, apart from Eckener, were convinced that everything was under control and it was absolutely safe.
In summary: With the exception of the USA, all airships were filled with hydrogen. In the early days, before, during and shortly after the First World War, there were a number of fatal accidents. The United Kingdom got out of the airship business in 1930 after the R101 accident. In Germany, the D-LZ127 was at the absolute peak of the airship era. They were in the air for years without any accidents, with hydrogen under the cover. Nevertheless, Eckener saw a great danger for the Hindenburg due to constructive differences. Helium was never delivered.
German belief in hydrogen: smoking rooms and safety measures

It wasn't that long ago that smoking bans didn't exist. People smoked everywhere: on trains, on buses, in TV studios, in parliament, even in hospitals and doctors' rooms, in the theater, on airplanes and so on. Of course, there was also a smoking room on board the Hindenburg, even though it was located in the hull and not far from it there were countless cubic meters of highly flammable hydrogen positioned as lifting gas.
Of course there were endless safety precautions, but the mere fact that there was a smoking room on board the hydrogen-filled Hindenburg is absolutely incomprehensible from today's perspective. In any case, this was not the cause of the Lakehurst accident, but it strongly shows the high level of conviction that the hydrogen danger is supposedly under control.
In summary: It was known that helium was safer than hydrogen, but they didn't get there. In addition, it was significantly more expensive and only the USA could have supplied it in the quantities required. This never happened due to the political situation. Since people in Germany were absolutely convinced that hydrogen was better and cheaper anyway and that all dangers could be ruled out, it would be absolutely safe. A fatal mistake that was the main cause of the Hindenburg accident, because no one really learned anything from the R101 accident or wanted to learn anything.
Security risks using the example of the “Hindenburg”: Why was the risk high?

The "Hindenburg" tragically became famous for its disaster on May 6, 1937, when it burst into flames while landing in Lakehurst, New Jersey. The risk of hydrogen is evident in the flammability of the gas. In this case, the hydrogen was probably ignited by electrostatic discharges or leaks in the hull. The exact cause could never be determined with absolute certainty due to the capabilities available at the time. But that does not change the undisputed fact that hydrogen caught fire and that is why a fire disaster occurred that cost many people their lives.
Despite all safety precautions and careful planning, the highly flammable gas could not be completely controlled. The burning hydrogen gas rose quickly, causing a catastrophic explosion. This is exactly the conclusion that people in Germany only came to after the Lakehurst disaster.
Hydrogen itself is not dangerous. But this statement cannot be made without the famous "it depends". The fact is that hydrogen is omnipresent in combination with oxygen in the form of water, water vapor and ice. Hydrogen is also produced in the human body during digestion. It is not dangerous. Many applications of this gas are also not dangerous, provided that care is taken to ensure that there is no ignition source nearby or that the combustion is controlled. For example, hydrogen can be used as an alternative to acetylene in oxyacetylene welding.
With regard to the use in airships, the question should be asked: Do you consider it safe and completely harmless to give children balloons filled with hydrogen to play with, for example at birthday parties? What happens if the balloon ignites due to friction? Or if a balloon "lands" on the birthday candles? If a leak occurs near a smoker? Do you really want to try this scenario? There is a good reason why people rely on safe helium for this application. If it is just a matter of making "Donald Duck voices", that could also be done with hydrogen. But do you want to expose yourself to a potential oxyhydrogen explosion? All of these thoughts should make it clear that hydrogen is dangerous in large quantities and, incidentally, airships have also been popular targets for lightning strikes in the past and one or two of these have ended tragically.
Hydrogen was used again in the LZ130, but there were never any passenger trips

The immediate consequences of the Lakehurst accident: The D-LZ127 was taken out of service for the time being. It could be viewed in the Frankfurt hangar for a fee. Although the LZ130 was completed, it was never put into passenger service. Only test, espionage and propaganda trips were carried out with it. There was no helium for this airship either, so hydrogen was used again.
Hugo Eckener, who was formally still the head of Luftschiffbau Zeppelin, no longer had much say in Germany. In the Nazi regime, which had now brought pretty much everything into line, he was at best tolerated. Hermann Göring also tolerated the airships, but only in the hangar so that he could give the order to scrap and blow up the halls. That was the end of the Zeppelin era, because all efforts after the Second World War failed. This statement refers to rigid airships and not blimps or semi-rigid airships.
Hugo Eckener himself said that, in his opinion, an airship filled with hydrogen will never be allowed to take off again. After the Second World War, he was of the opinion that a Zeppelin would no longer have any chance of competing with airplanes. That's why he was critical of the so-called Frankfurt Circle, which wanted to modernize the LZ-131 and get it into the air. The project never got beyond the idea phase due to a lack of money and the Zeppelin airship construction company, which still exists today and was still under the direction of Eckener at the time, had no interest in the construction.
The friendship between Zeppelin and Goodyear has stood the test of time to this day. Hugo Eckener, who, as is well known, recognized the danger posed by the Nazis early on, handed over all patents to the Goodyear company for safekeeping in a way that was not further clarified. In this way, they were supposed to be brought to safety from the Nazis, the war, and later also the occupying powers. The American company kept its word: when peace and stability returned to Germany, these were returned. At least officially, none of the technology was used at all. Things were different later, because Zeppelin worked as a supplier, consultant and know-how provider for Goodyear and had a decisive influence on their Blimps. Not to be forgotten: Luftschifftechnik Zeppelin, the manufacturer of the Zeppelin NT, delivered a few examples to Goodyear and that wasn't all that long ago. The company in question is a subsidiary of the still existing Luftschiffbau Zeppelin.
Could the Hindenburg accident still happen today?

With advances in technology and safety standards, the question of whether such an accident could happen again today is complex. Modern materials, advanced gas monitoring systems and improved safety protocols could minimize the risk. Helium as a filling gas is also more readily available today.
The emphasis is on "could". The problem is that there are factors that are unpredictable despite the most modern technology. It is certainly possible to produce completely sealed gas containers for airships. It may also be possible to shield them against electrostatic charges, making a Hindenburg scenario (sparks caused by electrostatic discharge after a landing rope touches the ground) unlikely. But do we know what really happens when lightning strikes? An airship is much too slow and flies much too low to be able to avoid one if it suddenly occurs. You can simulate it on a computer and carry out experiments in the laboratory, but you cannot predict how lightning behaves. In addition, there are striking differences between the frequent negatively charged lightning strikes and the rare positively charged ones. In terms of shielding and safety, this is extremely difficult to take into account in design.
One thing must not be forgotten at the moment: airships are a very easy target for potential attackers. You cannot really prepare for possible shelling or other dangerous things that could lead to the ignition of hydrogen. In dangerous times, it is important to take into account that criminals could misuse a hydrogen-filled cargo airship over a city, for example, as a means to an end for a terrorist attack. It would not even have to be "hijacked" for this; shelling from the ground could be sufficient.
In summary, there are a few points that speak for and against the use of hydrogen as an alternative to helium. These include:
- Modern technology: Advances in materials science and engineering could significantly reduce the risk.
- Hydrogen as a more economical option: Despite the risk, hydrogen remains a more cost-effective option for airship travel.
- Unforeseeable factors: Electrostatic discharge and unexpected technical issues could continue to pose challenges.
- Economic considerations: The use of helium could mean higher costs for production and operation.
- Improved security measures: Today's aviation industry has strict safety standards that minimize the risk of accidents.
- Helium availability: HNowadays, helium is more accessible and could serve as a safer filling gas.
Overall, the question of choosing the filling gas for airships remains a balance between safety and cost-effectiveness. While modern technology and improved security measures can reduce risk, economic considerations and availability of resources are still relevant factors. However, in view of tragic accidents in the past, it should be clear that hydrogen as a carrier gas cannot be an option for passenger journeys and that there would also be a high risk in the cargo sector.
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