6 ms·

France Is Dropping Concrete Bombs

68 points by riffer 15y ago

radagaisus 15y ago
This is brilliant.
Hominem 15y ago
Pretty sure the US did this during the first gulf war to destroy stationary targets without the pesky explosion.
- mnemonicsloth 15y ago
  Back in 1991, IIRC, missiles were smart but bombs were still dumb. The US seems to have started using concrete bombs in 1999 (against Iraq, but not during either gulf war). http://www.nytimes.com/1999/10/07/world/us-wields-defter-weapon-against-iraq-concrete-bomb.html http://www.nytimes.com/1999/10/07/world/us-wields-defter-wea...
  - icegreentea 15y ago
    They had 'smart' versions of bombs and missiles back in 91. They just didn't have GPS guided ones/cheap guided munitions. They have both now (with cheap in a relative term). http://en.wikipedia.org/wiki/Paveway http://en.wikipedia.org/wiki/Paveway
    - hollerith 15y ago
      To be specific, the relatively cheap GPS-guided bombs that became available after the 1991 Gulf War consisted of new electronics and new tail sections bolted onto ordinary "iron" bombs manufactured many years earlier. http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition
  - teamonkey 15y ago
    British forces used laser-guided bombs in 1991. The target was laser-painted by a Buccaneer, bombs were dropped by Tornado.
  - brudgers 15y ago
    Guided bombs were used in WWII. Laser guided bombs made their debut for the US in Vietnam [http://en.wikipedia.org/wiki/BOLT-117 http://en.wikipedia.org/wiki/BOLT-117] They were stars of the bombing campaign prior to the ground attack during the first Gulf War. [http://www.youtube.com/watch?v=md00oEyn6kg http://www.youtube.com/watch?v=md00oEyn6kg]
- neworbit 15y ago
  Very little collateral damage when you are hitting someone with a rock as compared to blowing up the surrounding block.
tamersalama 15y ago
I wonder how accurate you have to hit the target to get the intended consequences.
- mynameishere 15y ago
  I think you have to be very accurate with almost any kind of bomb. The soviets made 10+ megaton h bombs partly because they didn't have accurate delivery systems.
mmaunder 15y ago
To generate the force of a 1 ton TNT explosion, a shell shaped bomb moving at 800 ft per second will need to weigh 311,000 pounds. [K.E.=1/2 x m x v x v] It takes a fraction of this to dent a tank out of commission, provided you're accurate. The overpressure wave bouncing around inside the tank cabin created by a direct hit probably has stunning effects on the crew and may not kill them if the cabin isn't crushed - although it could do terrible damage to the ears, lungs and stomach.
- JofArnold 15y ago
  Or to look at it another way: v^2 = u^2 + 2as = 0 + 2 x 9.81 x 2,000 = 39,000 KE = 0.5mv^2 = 0.5 * 300 * 39,000 = 6MJ I.e. about 1kg of TNT. "Crush"?? I'm with you on this one, mmaunder
  - icegreentea 15y ago
    For another comparison, modern KE sabot anti-tank rounds (what tanks shoot at other tanks) use penetrators weighing from 4 to 8kg, with a muzzle velocity of around 1500m/s, giving a low of end of ~9MJ. Granted, this is ignoring air friction, and must punch through the front armor (much much thicker) than the top armor that bombs go through. Also... as a cost comparison, JDAM (the US GPS guidance) kits cost 20-30k per kit (you strap them onto 'dumb' bombs). For the actual bomb itself, you're talking on the range of a buck or two per pound... the inert training versions are much cheaper than that. Explosives are cheeapp. Silicon is pricey. See link below for pricing information! (The Mk-84 is the 2000lb 'dumb' bomb, it's listed along with its training/concrete version). http://www.fas.org/man/dod-101/usaf/docs/munition-cost-11-1.htm http://www.fas.org/man/dod-101/usaf/docs/munition-cost-11-1....
    - AdamTReineke 15y ago
      Just a thought, but if the silicon is expensive, could you potentially engineer the majority of the computerized parts into a UAV that could detach at the last moment and fly back?
nprincigalli 15y ago
Soon: imaginary bombs, weighting sqrt(-1) t :)
- foob 15y ago
  But then those bombs would be highly susceptible to decay!
merloen 15y ago
Wasn't there a military program for dropping metal rods from space? Does this sound at all familiar to anyone?
- neworbit 15y ago
  Yes - kinetic kill ideas are pretty sound. http://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Thor http://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Tho... Lifting that much mass into orbit is pricy though.
- tsotha 15y ago
  It was never a program, just an idea.
- aaronbrethorst 15y ago
  Sure, but only from Neal Stephenson's Anathem: http://anathem.wikia.com/wiki/Rod http://anathem.wikia.com/wiki/Rod
- hedgehog 15y ago
  Kinetic cruise missiles: http://en.wikipedia.org/wiki/Project_Pluto http://en.wikipedia.org/wiki/Project_Pluto
tsotha 15y ago
I wonder what they're using for guidance. GPS and inertial guidance aren't accurate enough and anyway aren't useful against moving targets. That leaves laser guidance kits, which tend to be pretty expensive. Probably takes more than one attempt on average, too. On the other hand, you probably don't need to worry much about temperature and humidity when you store concrete munitions. Or maybe they mix up a batch of bombs before the sortie - "You can't launch yet. The concrete isn't dry."
srean 15y ago
Well directed kinetic energy can be devastating and has been used for such effect since ages, for example the old canons with passive cannon balls. Rail guns are their new sought after variants. The famous bunker-busting smart-bombs circa first gulf-war were fin stabilized old tank barrels packed with explosives. It is their weight, owing to the high density metals used in the barrels and their small cross section (and hence extremely high terminal velocity) that gave them their extreme penetrative punch. Enough to pierce through tens of layers of strengthened concrete, each several feet thick and explode with devastating effects underneath. It was very important that they did not topple in flight though. So stabilization was critical. Even the modern anti-tank weapons are essentially glorified darts, but much, much heavier. They kill tanks by sheer kinetic energy alone. They have been found to be harder to defend against, compared to other variants like HEAT that penetrate tank armor by the use of a high speed, dense jet of liquid metal, or HESH which are sort of like cow-pies made of high explosives that set off spalling bending moments inside the tank 'hull'.
- hollerith 15y ago
  >hence extremely high terminal velocity the main benefit of the small cross section is not increased terminal velocity through the air but rather to maintain velocity through the bunker (or armor in the case of the "sabot" or APFSDS anti-tank round you mention)
xsmasher 15y ago
Shades of Heinlein's "Harsh Mistress" - launching is easy when you're "uphill" from the earth, and rocks are cheap.
bifrost 15y ago
This is an awesome idea. Even if the devices miss, they'll create terror in people thinking about the unexploded bombs.

68 points by riffer 15y ago

radagaisus 15y ago

This is brilliant.

Hominem 15y ago

Pretty sure the US did this during the first gulf war to destroy stationary targets without the pesky explosion.

mnemonicsloth 15y ago
Back in 1991, IIRC, missiles were smart but bombs were still dumb. The US seems to have started using concrete bombs in 1999 (against Iraq, but not during either gulf war). http://www.nytimes.com/1999/10/07/world/us-wields-defter-weapon-against-iraq-concrete-bomb.html http://www.nytimes.com/1999/10/07/world/us-wields-defter-wea...
- icegreentea 15y ago
  They had 'smart' versions of bombs and missiles back in 91. They just didn't have GPS guided ones/cheap guided munitions. They have both now (with cheap in a relative term). http://en.wikipedia.org/wiki/Paveway http://en.wikipedia.org/wiki/Paveway
  - hollerith 15y ago
    To be specific, the relatively cheap GPS-guided bombs that became available after the 1991 Gulf War consisted of new electronics and new tail sections bolted onto ordinary "iron" bombs manufactured many years earlier. http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition
- teamonkey 15y ago
  British forces used laser-guided bombs in 1991. The target was laser-painted by a Buccaneer, bombs were dropped by Tornado.
- brudgers 15y ago
  Guided bombs were used in WWII. Laser guided bombs made their debut for the US in Vietnam [http://en.wikipedia.org/wiki/BOLT-117 http://en.wikipedia.org/wiki/BOLT-117] They were stars of the bombing campaign prior to the ground attack during the first Gulf War. [http://www.youtube.com/watch?v=md00oEyn6kg http://www.youtube.com/watch?v=md00oEyn6kg]
neworbit 15y ago
Very little collateral damage when you are hitting someone with a rock as compared to blowing up the surrounding block.

tamersalama 15y ago

I wonder how accurate you have to hit the target to get the intended consequences.

mynameishere 15y ago
I think you have to be very accurate with almost any kind of bomb. The soviets made 10+ megaton h bombs partly because they didn't have accurate delivery systems.

mmaunder 15y ago

To generate the force of a 1 ton TNT explosion, a shell shaped bomb moving at 800 ft per second will need to weigh 311,000 pounds. [K.E.=1/2 x m x v x v] It takes a fraction of this to dent a tank out of commission, provided you're accurate. The overpressure wave bouncing around inside the tank cabin created by a direct hit probably has stunning effects on the crew and may not kill them if the cabin isn't crushed - although it could do terrible damage to the ears, lungs and stomach.

JofArnold 15y ago
Or to look at it another way: v^2 = u^2 + 2as = 0 + 2 x 9.81 x 2,000 = 39,000 KE = 0.5mv^2 = 0.5 * 300 * 39,000 = 6MJ I.e. about 1kg of TNT. "Crush"?? I'm with you on this one, mmaunder
- icegreentea 15y ago
  For another comparison, modern KE sabot anti-tank rounds (what tanks shoot at other tanks) use penetrators weighing from 4 to 8kg, with a muzzle velocity of around 1500m/s, giving a low of end of ~9MJ. Granted, this is ignoring air friction, and must punch through the front armor (much much thicker) than the top armor that bombs go through. Also... as a cost comparison, JDAM (the US GPS guidance) kits cost 20-30k per kit (you strap them onto 'dumb' bombs). For the actual bomb itself, you're talking on the range of a buck or two per pound... the inert training versions are much cheaper than that. Explosives are cheeapp. Silicon is pricey. See link below for pricing information! (The Mk-84 is the 2000lb 'dumb' bomb, it's listed along with its training/concrete version). http://www.fas.org/man/dod-101/usaf/docs/munition-cost-11-1.htm http://www.fas.org/man/dod-101/usaf/docs/munition-cost-11-1....
  - AdamTReineke 15y ago
    Just a thought, but if the silicon is expensive, could you potentially engineer the majority of the computerized parts into a UAV that could detach at the last moment and fly back?

nprincigalli 15y ago

Soon: imaginary bombs, weighting sqrt(-1) t :)

foob 15y ago
But then those bombs would be highly susceptible to decay!

merloen 15y ago

Wasn't there a military program for dropping metal rods from space? Does this sound at all familiar to anyone?

neworbit 15y ago
Yes - kinetic kill ideas are pretty sound. http://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Thor http://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Tho... Lifting that much mass into orbit is pricy though.
tsotha 15y ago
It was never a program, just an idea.
aaronbrethorst 15y ago
Sure, but only from Neal Stephenson's Anathem: http://anathem.wikia.com/wiki/Rod http://anathem.wikia.com/wiki/Rod
hedgehog 15y ago
Kinetic cruise missiles: http://en.wikipedia.org/wiki/Project_Pluto http://en.wikipedia.org/wiki/Project_Pluto

tsotha 15y ago

I wonder what they're using for guidance. GPS and inertial guidance aren't accurate enough and anyway aren't useful against moving targets. That leaves laser guidance kits, which tend to be pretty expensive. Probably takes more than one attempt on average, too. On the other hand, you probably don't need to worry much about temperature and humidity when you store concrete munitions. Or maybe they mix up a batch of bombs before the sortie - "You can't launch yet. The concrete isn't dry."

srean 15y ago

Well directed kinetic energy can be devastating and has been used for such effect since ages, for example the old canons with passive cannon balls. Rail guns are their new sought after variants. The famous bunker-busting smart-bombs circa first gulf-war were fin stabilized old tank barrels packed with explosives. It is their weight, owing to the high density metals used in the barrels and their small cross section (and hence extremely high terminal velocity) that gave them their extreme penetrative punch. Enough to pierce through tens of layers of strengthened concrete, each several feet thick and explode with devastating effects underneath. It was very important that they did not topple in flight though. So stabilization was critical. Even the modern anti-tank weapons are essentially glorified darts, but much, much heavier. They kill tanks by sheer kinetic energy alone. They have been found to be harder to defend against, compared to other variants like HEAT that penetrate tank armor by the use of a high speed, dense jet of liquid metal, or HESH which are sort of like cow-pies made of high explosives that set off spalling bending moments inside the tank 'hull'.

hollerith 15y ago
>hence extremely high terminal velocity the main benefit of the small cross section is not increased terminal velocity through the air but rather to maintain velocity through the bunker (or armor in the case of the "sabot" or APFSDS anti-tank round you mention)

xsmasher 15y ago

Shades of Heinlein's "Harsh Mistress" - launching is easy when you're "uphill" from the earth, and rocks are cheap.

bifrost 15y ago

This is an awesome idea. Even if the devices miss, they'll create terror in people thinking about the unexploded bombs.