NOVA aired a new program on the Hindenburg explosion last night. I do have an issue with their conclusion that it was an accidental spark igniting leaking hydrogen but I was quite amused seeing one of the researchers checking the conductivity of the mooring lines with a couple of multimeters. One of them was yellow and might have been some Fluke model. It was the other one that amused me, it was a red Cen-Tech multimeter available from Harbor Freight. It’s listed at $6.99 right now and I have two of those I paid less than $5 for. It’s a perfectly good multimeter for basic usage but it amused me to see it it in a laboratory setting. Like looking at the DNA testing laboratory and seeing a Gilbert Chemistry Set on the shelf.
Anyway, despite visiting the Zeppelin Museum to find out lots of info about the Hindenburg and mentioning some accidental fires they totally ignored the WWI London Terror Bombing that they produced an entire episode about which detailed how difficult it was to ignite the hydrogen in Zeppelins. The Brits needed to use specially designed incendiary bullets fired from a machine gun straight up through the bottom of a Zeppelin, in multiple passes before getting the hydrogen to ignite. Sure it could be a spark that lit up the Hindenburg but in this new episode they continued the idea that leaking hydrogen readily mixes with air in combustible proportions which was questioned in the previous episode.
I don’t know, but they sounded like they were ruling out sabotage without establishing why. It’s kind of tough to rule out sabotage in this case. They did present some evidence that there may have been a hydrogen leak ignited by a spark, but nothing conclusive.
A small fire of the exceedingly flammable chemically impregnated fabric would pretty quickly open enough hydrogen to the atmosphere to be stochiometric around the edges. At which point you quickly get an exponential feedback loop.
So the question isn’t (IMO) the feasibility of a spark directly igniting gas. It’s something (accidental or deliberate) igniting very flammable fabric. Whether that something was open flame, a shower of sparks from some mechanical dragging, etc., is IMO the real question.
Did you see the NOVA episode about the London Terror Bombing? It is not easy to ignite the hydrogen because it does not readily create a stochiometric mix to ignite. The fabric was not that easy to ignite either, rather the rainy conditions alleged to have a allowed the static discharge to create a spark would have made it difficult to ignite.
Oddly enough, the documentary aired in Australia over a month ago. As I recall, the explanation for the explosion being created by a spark, was that there were clear indications that hydrogen at the rear of the vessel had been leaking and forming an explosive mix with oxygen at the rear of the craft.
The only indication of an explosive mix forming was the explosion itself. That’s also a strong indication of every other possible reason for the explosion.
Mythbusters did a Hindenburg segment where they tested whether the explosion was caused by the silver paint that covered the Zeppelin, which contained the ingredients of thermite, though not in the same proportion. Although the myth was ‘busted’ in the sense that the paint-Impregnated fabric alone would have burned too slowly, the paint may have contributed along with the hydrogen. I remember watching the episode and I sure seem to remember the scale model Hindenburg with hydrogen and paint burning much more fiercely than the model with hydrogen alone.
But is that really an analogous situation? A bullet, even an incendiary bullet, passing through at high speed (and at altitude, no less, with less O2 in the atmosphere than sea level), with therefore limited opportunity for heat transfer to occur, versus even a glowing (but enduring) ember cause by a spark coming into contact with fabric in an O2/H2 rich environment, occurring at only a couple hundred feet above sea level as the zeppelin lands?
The fabric has been tested and ruled out as a factor here. Of course if something ignites the fabric it will end up igniting the massive amount of hydrogen in that airship, but that was not their contention. They claimed that a spark ignited leaking hydrogen. Maybe that’s what happened but what I find odd is that they ignored the evidence they laid out in an earlier episode that showed the hydrogen was difficult to ignite. And those bullets had a ton of time to ignite hydrogen inside and out of the dirigible, they were spewing burning phosphorous and ripping through the fabric and the numerous internal bladders of hydrogen without easily igniting any of it.
To be clear, I don’t know why the Hindenburg exploded. I do wonder why if someone tries to convince me of the reason they would deliberately leave out available information that brings their conclusion into question. That’s what lawyers would do, not scientists. Of course it’s something TV show producers do also, even on acclaimed science programs.
The thing about bullets—what I’m getting at—is this. They are traveling very fast. Although they may well have “a ton of time to ignite,” the speed they are traveling means there is not much time for heat transfer to occur. If a bullet were to strike something and become embedded in it, then sure, it’s got all the time it needs. But if it’s just passing through a bladder, in one end and out the other with an atmosphere, that’s not much time in vicinity of the same pocket of gas (the gas isn’t going to travel with the bullet so much: the bullet is just passing through).
A spark landing on something, on the other hand, may have all the time it needs, even if it doesn’t burn as hot as a phosphorus bullet.
I am not saying “this is definitely how it happened,” only noting that just because an incendiary bullet passing through at high speed isn’t guaranteed to ignite an explosion, doesn’t mean a spark that becomes embedded in… anything at all (be it fabric, paper, other structural material, etc) in the same (or more favorable, at sea level) atmosphere can’t cause an explosion.
I think you are underestimating the amount of time these bullets had to pass through an enormous airship and the amount of burning phosphorous it was spewing in a spiral trail as it went. These weren’t tracer bullets, they were designed specifically for this task. And there are serious questions about how readily hydrogen mixes with air to form a combustible mixture. Remember that the hydrogen isn’t pressurized, these aren’t blimps, the hydrogen bladders are at atmospheric pressure, a leak or a bullet passing through them doesn’t result in hydrogen spewing out like a bullet hitting a propane tank in a special effects scene.
And again, I’m just noting these things weren’t considered in this episode of NOVA. I don’t know if they had any previous episodes before the one about the London Terror Bombing, but maybe they need another one to have the experts look at the broader set of evidence and address all of it to come up with an overall inconclusion.
There were several new interesting details presented in this episode also, the first look at new footage of the explosion from an angle never seen since the incident and some details on the construction of the fabric envelope and how it was attached to the frame.
If you look at it another way, the difficulty of downing Zeppelins in WWI can be an argument against sabotage. They were hard to ignite on purpose. The ignition source had to be combined with a lot of luck…or bad luck. Chance has a better success rate with things like that than human intentions.
I don’t know if chance has a better success rate, but the primary argument against sabotage is a lack of evidence. It is pure speculation. But even if it was sabotage I don’t know if some simple explosive would have ignited the airship like that, the intention could have been to simply disable the ship and by chance the whole thing went up. I don’t see any way to draw a strong conclusion here based on what is known.
Yeah, I got a chuckle about the Cheapo Meter as well. They give them damn things away with the coupon!
Overall, this episode fell kind of flat with me. Kinda telling us what we already knew. And I wonder if that math guy didn’t come up with the 4 minute estimate of how long it would have taken to build up enough charge by knowing thats what he needed to come up with. What do they call that? I dunno.
The new footage of it torching was very cool, however. But the need to ‘authenticate’ the film was stoopid. C’mon! It’s the real deal. Was there really any doubt??? That was some plain old filler right there. Like watching that History Detectives crap.
I thought it was kind of interesting. The new found footage may have driven the renewed investigation and they recorded a lot of video about it, but it turned out to reveal no new significant information. They had the footage so not surprising that they used it.
But they could have used more time to further investigate the static discharge hypothesis with discount test equipment. Their explanation of their test and the entire concept is missing a lot of detail.
What the NOVA producers did was just about was needed to get confidence that this unique footage from a different point of view from the Hinderburg was not a deep fake or a purposely degraded computer simulation as it is possible to do nowadays.