I’ve seen mention of them on the news, saying that they can burrow down 20 feet before exploding. No more details than that, though. Anyone know?
They have an extremely tough casing and a delayed fuse. Basically, the bomb doesn’t go off till a few seconds after it hits the ground. This allows the bomb to penetrate (or burrow into the structure or ground) as far as possible before it explodes.
I’m not certain but it might also use a shaped charge that directs the force of the explosion mostly forward as opposed to a basic spherical blast. In a spherical blast much of the energy from the bomb is wasted as it blasts harmlessly into the air. The more you can direct at your target the better.
BBC explained it nicely for me. I take it the Russkies didn’t use such a thing?
Waitaminnit - I may not have look closely enough at the article, but how does it penetrate 20 - 30 ft deep?
- sheer velocity?
- Shape of the nosecone (if that is the right term)?
- Mechanics of the nosecone (e.g., has some sort of drill bit on the tip)?
- Explosives (i.e., some sort of mini-bomb on the front of it)?
- Some other way?
I don’t think there are any ‘moving parts’ in the tip that make it penetrate the ground. Apparently, it’s just a really heavy bomb with a hard, sharp tip that penetrates the ground with kinetic energy, kind of like a dart. Unless I’m wrong.
Here is another article, an interactive graphic from the Guardian Unlimited site, which shows and tells how these are supposed to work.
http://www.guardian.co.uk/flash/0,5860,567593,00.html
Basically, it’s dense, hard, fast, and the charge is placed rearward the better to force the projectile forward.
Interestingly, they are made from worn out artillery barrels.
Bit-o-trivia: These bombs were created specifically to attack Iraqui bunkers during Desert Storm. The first ones were assembled and shipped to the Air Force so fast they were still warm (literally - the explosive charge has to be heated to be poured into the bomb) while they were being hung on the planes that would drop them!
That is true but the idea of penetrating bombs goes further back than this. Among others the Durandal anti-runway bomb was designed in the early 80’s to penetrate concrete (or whatever) so it would blow bigger holes in runways than typical bombs. The Durandal actually uses a rocket motor to propel it forward (it’s dropped like a normal bomb but once the nose is pointed downward towards the target the rocket motor fires).
For the bunker buster bombs being mentioned here I think Bob Scene is correct in that it merely uses its 5,000 lb. weight falling from a great height to drive it into the ground or bunker.
Picture a nail being driven into a board. Not much different, it just uses its own weight and speed as the hammer.
Quite a hammer it would be also: It weighs 4,637 pounds, and contain 630 pounds of high explosives (Tritonal). It is a little over a foot in diameter and about 19 feet long. Essentially, a 20 foot long nail with explosives in it. With that weight and very small cross section it would hit the ground with incredible speed.
Several years ago I got a chance to visit the museum at Watervliet Arsenal where the Bunker Busters were produced for the Gulf War. They had a very good videotape that showed exactly how it was made and how it was supposed to work. At that time you couldn’t get a copy of it, I asked. I went to their web site and I don’t see any mention of it at their museum section. If you check out their section on Manufacturing Capabilities you’ll see some of their abilities. Maybe by contacting someone over there you could get some serious info.
Homepage…
http://www.wva.army.mil/
Gotta teach you youngsters some history.
The British Royal Air Force used “bunker-busting” type bombs in WWII against heavy fortifications like u-boat pens and V1 launch sites. A unit called the Dambusters* flew heavily-modified Lancaster bombers, and dropped 12,000 lb “Tallboy” and 22,000 lb (10 tons!) “Grand Slam” bombs from high altitude (well, high for WWII bombers), and by the time they hit the ground, the bombs were travelling well in excess of the speed of sound. Although they could penetrate reinforced concrete, they worked best when dropped in the relatively soft soil right next to a buried fortification. They would go off after drilling deeply into the earth, concentrating the explosive force against (or underneath) the fortification, shattering it.
If dropped accurately (no small feat for high altitude bombing in WWII) they were very effective.
*The Dambusters got their name from their first raid, to destroy the Mohene and Eder dams in the Rhur valley. They used a different sort of bomb than that described above: this one was dropped from low altitude over the dam reservoir, skipped across the water and sank next to the dam wall. The explosion cracked the dam and the weight of the water collapsed it.
The Dambusters went on to become the RAF’s premier high-accuracy specialist bombing unit.
The warhead design is patterned after a masonry nail (as scotth alludes to) and weighs nearly 5,000 pounds, which is what allows it to bust through all that concrete.
Check out this Washington Post link to get a close-up view of the GBU-28, and Navy test photos of it in action on a mock bunker.
The “bomb” probably a guided missile, fires a preliminary charge to open a hole then a steel rod punctures a hole next you have the main blast. This is an oversimplified explanation.
Everything you would need to know about the weapon.
AGMThe Conventional Air-Launched Cruise Missile (CALCM) is an affordable, long-range standoff weapon that has proven itself in combat in Operation Desert Storm, Desert Strike, Desert Fox and Operation Allied Force.
CALCM is produced by modifying surplus nuclear-armed AGM-86B Air-Launched Cruise Missiles (ALCM). CALCM Block 0 and Block I configurations feature a high explosive, blast-fragmentation warhead and a Global Positioning System (GPS) receiver for accurate GPS-aided inertial navigation. Launched from B-52H aircraft, CALCM provides the US Air Force with an economical, rapid response, worldwide conventional strike capability, making it a cost-effective choice for additional system upgrades and new mission applications.
-86D - Hard Target Defeat Capability
Precision strike accuracy combined with an advanced penetrating warhead will be incorporated into the AGM-86D CALCM to provide an enhanced capability against hard and deeply buried targets. A Foreign Comparative Test (FCT) program was initiated in June 1997 to evaluate the integration of the British Aerospace Royal Ordnance BROACH/Multiple Warhead System (MWS) with CALCM.
The MWS uses a shape charge and a follow-through penetrator to perforate reinforced concrete targets in excess of 10 feet. A successful sled test of the MWS in a CALCM fore-body was conducted in the United Kingdom in May 1998. In a dynamic sled test using a BROACH, the CALCM missile successfully penetrated a reinforced, 12-foot-thick concrete target. Two verification sled-tests of the MWS in CALCM will be conducted in late 1998 at Eglin AFB, Florida.
The Lockheed Martin, US-developed Advanced Unitary Penetrator (AUP-3M) warhead is also being evaluated for CALCM. Sled tests of that configuration against similar concrete targets are planned for fall 1998. The Air Force is conducting a Cost Benefits Analysis (CBA) of the two warhead alternatives and will make a selection of a CALCM AGM-86D warhead based upon performance, cost and risk by the end of January 1999.
The Defense Special Weapons Agency (DSWA) has included funding for CALCM AGM-86D in FY99 through FY01. Productionization of the AGM-86D missile would begin by March 1999, with flight tests in the second quarter of 2001, followed by production of an initial lot of up to 85 missiles. Existing requirements to attack select targets from long stand-off ranges may generate additional production.
Nahhh… more like a jart.
From scotth’s explanation, I guess they don’t rotate like a bullet and drill themselves into the ground. Or I guess they would screw themselves into the ground, which makes our pilots screwdrivers, and the Taliban just gets screwed.
(I’ll consider weapons ‘sexy’ when my idea of sex includes high explosives.)
[QUOTE]
*Originally posted by Derleth *
**
s/Or I guess they would screw themselves into the ground/Or I guess they don’t screw themselves into the ground/
s/or/ry
Poloin99, just a friendly note: when quoting material in a post, it’s customary to cite the source of that material with a link or if it’s not online, with a notation: “text from The Boeing Company’s CALCM briefing material, copyright 2001”. Otherwise it will look like you plaigarised it, and that’s frowned on around here.
Kamandi, Apologize for the negligence. I will implement your advice in the future. Here is the address: http://www.boeing.com/defense-space/missiles/calcm/calcm.htm
Could you please tell me how to insert a link and if possible how to insert a quote with lines above and below.
Thank you