USAF re-invents the Grandslam

[Navaleye]

From Strategypage with the usual health warning:

November 15, 2004: The U.S. Air Force has backed off on building a nuclear deep penetration bomb, and is instead going with one using conventional explosives. The new bomb, the Massive Ordnance Penetrator (MOP), will weight 15 tons and be carried internally by the B-2 or B-52 bombers. The MOP will be guided, by GPS (as well as other methods as a backup.) First test models are to be available in 2005. Operational characteristics (how deep the bomb can go in different types of material) has not been announced. And probably won’t be, as you would want to keep that data secret lest the bad guys dig too deep for MOP to reach them.

PS: Anyone else read "A hell of a bomb"?

[ZH875]

Isn't this the bomb previously referred to as 'MOAB' - Mother Of All Bombs. (Massive Ordnance - Air Burst)

[Navaleye]

No, that was an updated version of the Daisycutter at about 15,000lbs. This is a different beast altogether. IIRC, the USAF did have a Grandslam style weapon after WW2. A B36 could carry two externally, so I guess they are drawing on that experience.

The only real problem with the Grandslam was not the bomb itself, but the height it was released from. I think the Lanc struggled to get to 15,000ft. The designed dropping height was 40k ft. The other not so small matter is how do you stop a bomb breaking apart when it hits 60ft of reinforced concrete?

[Gainesy]

At Boscombe a few years ago, I'm sure I saw a Grandslam (or Tallboy) rusting away near the MT section; anybody confirm? It was just the nose section, no tail cone or fins.

[Razor61]

The MOAB (GBU-43) is replacing the 15,000Ib Daisy Cutter. It is currently rated at 21,700Ib.

http://www.globalsecurity.org/military/systems/munitions/moab.htm

The link has a video of the MOAB delivered by an MC-130E and exploding on the range at Eglin.
Also shows the relative size compared with Tall Boy and Grand Slam....

Razor

[bigflyingrob]

Ah nice to know the USAF have finally managed to convince themselves the earthquake bomb was theirs and not Barnes Wallis. Now they can build them without feeling second best

[Pontius Navigator]

There is a Grand Slam and a Tall Boy at the BBMF at Coningsby. There is also a Grand Slam at Ludford standing on its nose by yje old level crossing.

The Tall Boy at 12,000 lb was apparently the better of the two bombs. It was slimmer and less prone to breaking up on impact. The Grand Slam on the other hand was a real earthquake bomb when dropped on the bridge viaduct (polesti?) but then the ground was not reinforced concrete.

Against the Tirpitz the 12,000 lbs were much better. Only problem was you had to hit or at least get the bomb under it - one shot. With GPS and Barnes Wallis who knows what Bomber Harris might have achieved. Imagine 20,000 individually aimed bombs PER NIGHT.

[Navaleye]

Pontius,

With a GPS Tallboy the war would have been over in a month. Two viaducts were hit by Grandslams, one was Arnsberg the other Bielefield. I got to go round the Valentin U-Boat factory which was hit by several tallboys and grandslams. It looked like a lunar landscape.

[Pontius Navigator]

Navaleye, mind you the Axis did much better than the allies when it came to PGMs and missiles so just maybe the war would have been over in a month, auf weidersen!

[Navaleye]

Yes that's true, but they were relatively small devices in comparison to a Grandslam or a Tallboy, the shear wallop of this things must have been quite something. Even when they couldn't penetrate a structure the concussion they caused must have been (to quote George W. Bush) "Horrocias"

[Pureteenlard]

Bielefeldt viaduct? I apologise for the spelling but I can recall the name but not the correct sequence of letters . . .
I'm sure I read an account of a span, on being struck by grandslams at either end, lifting up and being hit whilst airborn dead centre by a tallboy.
That might be my fevered imagination, a tall(boy?) story or yet another myth spontaneously created in the depths of the interweb.

[Archimedes]

Isn't that in Brickhill's The Dambusters ? I know I read this (although how true it is...) before the internet was anything more than the playthings of a few computer experts...

[Pontius Navigator]

Pureteenlard, Bielfeldt, you're right. Polesi was the oil refinery.

It could well have been Brickhill as Archimedes says. I recall that the effect wa sto create a camouflete and cause the viaduct suspension to collapse as the underlying ground structure was pulverised.

[Air-Geko]

Now why is it I think the daisy cutter (M.O.A.B.) and the deep penetration ordinence are two completely different items? I seem to recall that the daisy cutter is primarily an A.P. bomb designed to explode 10-15 feet off the deck via an extended probe -- shredding everything within sight whereas the penetration bomb is designed NOT to detonate upon impact but rather detonate at "deck minus 60 or so." And lastly wasn't someone experimenting with using a capped tank cannon tube (with added stabalizing fins) to create the explosive "delivery device"?

Just the recollection of an old dude....

Air-Geko

[Red Line Entry]

Six Foot have a Grand Slam and a Tall Boy at the entrance to their HAS site (also have what must be an empty barrel of 80 shilling between them...).

IIRC, the idea of the Grand Slam was NOT to directly hit the target. Getting the earthquake effect was the principle objective and to do this the bomb had to land near, but not on, the target.

[BEagle]

The oil field was at Ploesti, Romaia.

Air-Geko, yes, the 5000lb GBU-28B 'Deep Throat' pentrator weapon used at the end of GW1 was indeed constructed from surplus 8" artillery barrels. Only 2 were dropped in GW1, but they worked as advertised and could penetrate over 20 ft of reinforced concrete.

The 21000lb 'MOAB' is totally different and follows on from the 15000lb BLU-82 'Daisy Cutter', originally intended to facilitate instant helicopter landing pads in Viet Nam. This produces a massive overpressure which can punch holes in minefields and turn anything within the blast radius to jelly.

Part of the psyops on GW1 was to tell an Iraqi unit to move out and surrender, because the next day the world's largest bomb was going to be dropped on them. They didn't and it was.....

[Pontius Navigator]

Air Gecko, while the 1000lb bomb is known as a General Purpose bomb it used to be two very specific models.

For airburst, with a radar airburst fuze, the bomb body was made of cast iron to aid fragmentation. If impact, penetration and shock are required the forged body would be used. Externally they looked the same.

To crater a runway the forged bomb would be prefered for the concrete but the cast would be better on the soft ground. The Stanley impact stick was probably with all cast bombs, Mark 11s I think, but I am both guessing and surmising here.

The GP replaced special AP or armoured piercing bombs in the 50s. I don't know if the modern mark 22 has an alternative hard version.

Now that we are moving to 'effects based warfare' weapon/target matching is taking on a fresh meaning. Bit like the guns/amraam for air policing debate.

[BEagle]

Incidentally, the US also used the UK's 12000lb Tallboy design in the Trazon bomb of the early 1950s. This was a steerable large bomb and was reasonably succesful for its time. However, it was rendered obsolete by contemporary nuclear thinking.

[HectorusRex]

A side link from the original "Global Security" site gives a very full account of the design and construction of all the very large bombs designed by Barnes Wallis.

http://home.aol.com/nukeinfo2/

Production was shared beteen UK and USA.

[Pontius Navigator]

Curiously enough this month's FOCUS carries a book review on 'Barnes Wallis' Bombs: Tallboy, Grand Slam and Dambuster, by Stephen Flower @£25.

These earthquake bombs were only superseded in destructive power by the atom bomb.

Not only that, but there was a talk in Woodhall Spa on Sunday by one of the 9 Sqn Bomb Aimers on the Tirpitz raid. The Tallboys that missed destroyed the bed of the fjord and this allowed the Tirpitz to turn turtle. Had they not cratered the sea bed it was possible that the ship would not have inverted.

[Grimweasel]

And there was me thinking the 'Grand Slam' was the involuntary cr@pping, pi$$ing and chundering of one's self apres many swills when in one's pit at night!!!! :O :O :O

[Melchett01]

That might be my fevered imagination, a tall(boy?) story or yet another myth spontaneously created in the depths of the interweb.

No old bean, your imagination isn't working over time. They did drop a tall-boy against said viaduct having failed dismally to schwack it on many many previous occassions.

Have seen the cine-camera footage of it on a course - and there was one hell of a bloody big hole in the middle of it caused by the earthquake effect when the bomb went off slightly to one side. Almost as devastating as my arse the morning after a vindaloo.

[tony draper]

I thought the Tallboy was designed to be dropped alongside rather than directly on the target, seem to recall reading or seeing that somewhere, of course its a good line if you miss slightly,
"ah its ok twas meant to do that"
:rolleyes:

[Pontius Navigator]

tony, as far as a concrete bunker (submarine pen) the TB was designed to explode in the pen. No prizes for a near miss. Shake the water about a bit but hardly an earthquake.

Against a bridge pier OTOH the huge camoueflet caused by the bomb would totally wreck the ground structure and cause structural failure of any adjacent structures.