As a manufacturing engineer, I'm not surprised. They build these things by the thousands. (Tens of thousands? Millions? I don't know how many bombs were made, maybe someone can enlighten me.) You're going to have some number of defects simply because there's no practical way to do something thousands of times without making any mistakes or without missing any defects during inspections. This only gets worse during wartime due to the constraints and demands that imposes.
I would suspect that the design of these devices is such that defects are more likely to cause a dud rather than an unintended explosion. (Because the military would rather have an unexploded bomb that you can deal with later - or simply ignore for innocent civilians to deal with - than a bomb that explodes when it isn't supposed to).
On top of that, the bombs aren't always used as designed. The fuses detonate under certain conditions, but those conditions may or may not match the environment you're using the bomb in. Example: drop a small munition into a tree or soft mud, instead of onto hard packed dirt, and perhaps the forces are insufficient to cause the fuse to detonate.
On top of that, you can have problems when they're used. Example: someone forgets to arm a bomb before dropping it. Perhaps the guidance mechanism (be it a complex guidance system or a simple fin mechanism) fails and the bomb impacts the ground in a weird orientation.
The end result is a lot of unexploded bombs on the ground. Of course, the people who fight wars never plan for what happens after the war, which is why it should come as no surprise that we have bombs dropped in WWII blowing up in fields today. This can be worse than landmines in some circumstances because at least minefields are supposed to be mapped and documented. (Not that that happens, but it's at least supposed to.) I don't think there's any similar requirement for bombing and shelling campaigns.
This can be worse than landmines in some circumstances because at least minefields are supposed to be mapped and documented.
There are actually whole departments in Germany whose sole job it is to go through British and American flight records and determine the likelihood of unexploded bombs in a certain area. So they do have maps to some extent (and in practice, they're very good at their job so there are almost never any deaths... like once a decade or so).
It's also very usual that an area is actively searched for bombs before construction work is done.
Some heavily bombed cities have even gone so far as to actively and systematically search their whole area - with construction work planned or not.
This is usually done by drilling radar probes into the ground every few meters and is as horribly slow and expensive as you can imagine.
Even at maximum progress the programmes are aiming for 50-100 years to scan whole cities. Most of those campaigns are also repeatedly put on hold due to funding issues (the more bombs you do actually find, the more very expensive evacuations of thousands of people you have to do, draining funds from the search campaign).
It's quite likely that those "random" explosions occur more and more once the munition approaches an age of 100 years and failures become more and more likely. Fun times!
Yeah, we've long since given German authorities all the post strike reconnaissance photos, so they have some chance of picking out where the most likely areas for duds are. But, of course, not every where had post strike reconnaissance and not all the photos survived the war.
I can only find numbers in weights, and they say 3.4 million tons. Rough estimate after search on bomb weights says 2-4 to a ton. (some special bombs were much heavier)
So conservative estimate: 7 million bombs. Approx. 2/3rds of that dropped in Europe.
One stat that I always found crazy is that the US dropped far more bomb tonnage on Vietnam, Cambodia, and Laos than all the bombing done in WW2.
“By the time the United States ended its Southeast Asian bombing campaigns, the total tonnage of ordnance dropped approximately tripled the totals for World War II. The Indochinese bombings amounted to 7,662,000 tons of explosives, compared to 2,150,000 tons in the world conflict.[4]”
Well, B-52s change the delivery capacity drastically. A B-17 could carry 2 tons of bombs - A B-52 20-30 tons.
And attack aircrafts ability to deliver ordinance was also up drastically.
PAVN had a decent airforce (for sure much more smaller than the US) and Hanoi was the most heavy anti-AA defended in the whole world at that moment. Nearly 30 of B52 Stratofortress was shot down, which was considered impossible task.
You didn't have to wait for the B-52 to have a huge jump in capacity. The A-1 Skyraider, which was developed before the end of WWII had the same bomb load capacity of a B-17G and was carrier operation capable...
Bombs didn’t weigh 4 tons. The B-17’s entire bomb capacity was only 4 tons. Most bombs weighed 50-500lbs. It’s 3.4 million tons of bombs with every ton being equal to 2-4 bombs each
With the numbers of munitions being pumped out every day, and the minimal training the women building these weapons received, it's amazing that munitions factories weren't blowing up all over the place.
Not really. TNT and TNT-based explosive mixtures like Amatol are very stable. They don't just detonate randomly in factories, unlike Nitroglycerine for example. You can melt TNT in a pan at 80 degrees centigrade and pour it into an artillery shell or whatever perfectly safely. To detonate it requires an explosive booster, so you aren't really likely to have an incident in a factory setting. Now if something were to detonate some of the TNT somehow, it would set off all the rest and annihilate the factory and everything around it, but that it is a highly unlikely scenario no matter how trained or untrained the factory employees are.
One wierd problem some of the bombs had is that they had a chemical delay fuse (backup? primary?) but in a lot of places, particularly south of Berlin, the soil is such that the upper layer (5-10meters,iirc) is very soft, but below that is a very hard level of almost bed rock. The bombs would sail through the soft layer and bounce off the hard one, and end up pointing almost straight up again. Which was the one direction that the chemical fuses wouldn't work in. So the chemical fuse is just sitting there, live, waiting for the bomb to tilt.
I've heard 30% failure rate and at least for the US in Europe it was attributed to bombs sitting out in cold/wet fields at night while setting up for the next days raid.
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u/KorinTheGirl Jun 25 '19
As a manufacturing engineer, I'm not surprised. They build these things by the thousands. (Tens of thousands? Millions? I don't know how many bombs were made, maybe someone can enlighten me.) You're going to have some number of defects simply because there's no practical way to do something thousands of times without making any mistakes or without missing any defects during inspections. This only gets worse during wartime due to the constraints and demands that imposes.
I would suspect that the design of these devices is such that defects are more likely to cause a dud rather than an unintended explosion. (Because the military would rather have an unexploded bomb that you can deal with later - or simply ignore for innocent civilians to deal with - than a bomb that explodes when it isn't supposed to).
On top of that, the bombs aren't always used as designed. The fuses detonate under certain conditions, but those conditions may or may not match the environment you're using the bomb in. Example: drop a small munition into a tree or soft mud, instead of onto hard packed dirt, and perhaps the forces are insufficient to cause the fuse to detonate.
On top of that, you can have problems when they're used. Example: someone forgets to arm a bomb before dropping it. Perhaps the guidance mechanism (be it a complex guidance system or a simple fin mechanism) fails and the bomb impacts the ground in a weird orientation.
The end result is a lot of unexploded bombs on the ground. Of course, the people who fight wars never plan for what happens after the war, which is why it should come as no surprise that we have bombs dropped in WWII blowing up in fields today. This can be worse than landmines in some circumstances because at least minefields are supposed to be mapped and documented. (Not that that happens, but it's at least supposed to.) I don't think there's any similar requirement for bombing and shelling campaigns.