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| writing:airships [2025/11/20 03:41] – [Lift Gas Types, Sources, and Storage Requirements] JacobCoffinWrites | writing:airships [2025/11/20 03:44] (current) – [Relevant Technological Advancements] JacobCoffinWrites |
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| double hull of inert gas to keep out the oxygen that hydrogen needs to mix with in order to form a flammable or explosive mixture. That’s how fuel tankers were rendered safer after the SS Sansinena explosion, and airliners as well after the TWA Flight 800 explosion. Carbon dioxide and nitrogen, respectively, are used to inert the empty spaces in partially full fuel tanks, which would become giant fuel-air bombs otherwise. | double hull of inert gas to keep out the oxygen that hydrogen needs to mix with in order to form a flammable or explosive mixture. That’s how fuel tankers were rendered safer after the SS Sansinena explosion, and airliners as well after the TWA Flight 800 explosion. Carbon dioxide and nitrogen, respectively, are used to inert the empty spaces in partially full fuel tanks, which would become giant fuel-air bombs otherwise. |
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| | === Hydrogen Safety Features === |
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| | Historically: Handling hydrogen safely for large airships used to be a matter of three things: purity, ventilation, and electrical conductivity. Zeppelins acted like giant faraday cages for lightning strikes and static electricity, keeping them surprisingly safe unless there was a major leak at an inopportune time (which is how the Hindenburg, whose skin was not fully electrically conductive under certain atmospheric conditions, ended up being the first and last fatal accident for the Germans’ civilian Zeppelin airline after nearly 40 years of operations, during a time when a plane fatally crashed after only a few hundred hours of operation on average). Ventilation between the gas cells and outer hull ensured that no dangerous concentration of hydrogen and oxygen could build up over time from gradual effusion. And, of course, pure hydrogen doesn’t burn, which is why Zeppelins were able to terrorize Britain in the first few years of World War One with near-impunity before the incendiary bullet was invented. |
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| | In the modern day, though, we have higher standards for safety, and thus airliners and fuel-carrying ships both use inert gases like nitrogen or carbon dioxide to prevent explosive fuel-air mixtures from forming. An airship could do the same, using a balloon-within-a-balloon method, or by sealing the outer hull of a rigid airship and filling it with with nitrogen instead of just trusting to ventilation systems instead. |
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| | Interestingly, we do know that this would work in a practical sense for hydrogen, because of experiments conducted by the British in World War I. Prior to late 1916, it was initially thought (before the discovery of helium on earth!) that the Germans had discovered a nonflammable lift gas, since simply shooting Zeppelins didn’t catch them on fire, and it took sustained artillery and flak barrages from ground batteries or teams of warships to actually sink the small handful of Zeppelins that they did manage to bring down. Others thought that the Zeppelins were using an inert gas to surround the hydrogen cells, and thus “armor” them against flame, possibly using exhaust gases. |
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| | To test this, the Brits fired the experimental Very’s and Pomeroy incendiary bullets they were developing into a double-layered balloon of hydrogen and a nonflammable gas mixture. The Very’s and Pomeroy bullets were fired through the top where the hydrogen would escape, and burned all the way through the bottom of the balloon, which itself was flammable, and it still didn’t catch the hydrogen on fire. It was, in their words, “completely protected” against ignition. |
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| | As it would later develop, the Germans were not in fact using inert gases in this way, instead trusting to hydrogen purity and ventilation, but the record still stands. Now imagine if the balloon itself was fire-retardant, like coated synthetic fibers, which would just melt rather than combust if subjected to a hot flame. Imagine if there were sensors to detect hydrogen leaks, and if the ship was constructed from all-conductive materials. They’d be essentially as safe as helium airships, which themselves proved to be much less prone to fatal accidents even during the rigors of World War II than ubiquitous modern helicopters like the Robinson R44 (fatal accident rate of 1.3 per 100,000 flight hours vs. 1.6). In the modern day, the Zeppelin NT semirigid airships currently used by Goodyear and sightseeing companies haven’t had a single fatal accident since they started operations in the 1990s. |
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| | **Modern day features:** |
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| | Passive Safety Features: |
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| | To safely store Hydrogen an airship can have a double hull of inert gas like helium, nitrogen, and/or carbon dioxide to prevent fires or explosions, in addition to active safety measures. Alternatively, a direct mix of isobutylene and carbon dioxide can render hydrogen fires self-extinguishing and non-explosive across hydrogen’s entire ignition range, but this mixture has somewhat less lift than helium, thus probably isn’t as desirable as a double hull. |
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| === Electrification === | === Electrification === |
