RAF 'Tall Boy' and 'Grand Slam' bombs

[Warren Thompson]

Were these deep-penetration weapons ever used on 'soft' targets? Were they ever used by the USAAF?

[Aufklarung]

Hi
Tall Boy was used against a railway tunnel and Grand Slam against a Viaduct. Over 800 of the first and something like 40 of the latter were used during the war. Is this what you mean by "soft targets"?

http://www.bismarck-class.dk/tirpitz/mi ... llboy.html

http://www.tecsoc.org/pubs/history/2003/mar14.htm

I could find nothing showing the USA used these bombs but they did design an Aircraft (XB-45) capable of lifting those specific bombs.

http://www.wpafb.af.mil/museum/research ... 4/b4-7.htm

Hope that is of some help to you.

regards
A

[Warren Thompson]

Thanks. I'd heard of their use v. the bridge and the tunnel. Were they ever used on unreinforced buildings?

[Vinnie O]

I've seen photos of a B-29 being loaded with a Grand Slam and then dropping it (on a test range in the US). The bomb had to be placed in a concrete-lined trench and the B-29 towed over it because the B-29 was too close to the ground. The doors to all 4 bomb bays were removed and a portion of the fuselage may have been carved off to fit the widest part of the bulge.

The "Green Book" volume on the US Ordnance Corps in WW2 describes the effort to manufacture Grand Slams in the US, which was done using welded up sections of "pipe", rather than a single large forging. The US was in the position to start cranking them out like hot dogs.

Not satisfied with the 22,000 lb. Grand Slam, the US (Army Ordnance Corps) produced a 42,000 lb. version, which could have only been carried by a B-36 (expected in 1946). The 42,000 lb. bomb did not receive a separate designation, probably because it never finished qualification. The US Army Air Force did extensive drop tests of the 22,000 lb. bomb to develop ballistic data (to feed into the Norden bombsight?).

If the war against Japan had continued for a few more months, Grand Slams would have arrived in the Pacific and been dropped by B-29s. The English had no base close enough to bomb Japan with Lancasters.

The Grand Slam (and Tall Boy) were intended to damage targets by earthquakes rather than direct hits. The direct attacks against submarine pens (which proved pointless) were an exception. Any large structure that might be rendered inoperative by shock to its foundations could have been attacked by "deep penetration" bombs. I think the claim to fame was knocking down an aquaduct.

[Warren Thompson]

RAF Bomber Command's last raid of the war was 25 April 1945 (I think) and directed at Berchtesgaden. Were either of these bombs employed then?

[Warren Thompson]

As well, I seem to remember that deep-penetration bombs were used against the Watten Bunker, Eperlecques (a planned-for V-2 assembly and launching site), hitting one corner of the structure.

[Andy H]

If the war against Japan had continued for a few more months, Grand Slams would have arrived in the Pacific and been dropped by B-29s. The English had no base close enough to bomb Japan with Lancasters

I have posted somewhere on the forum that at the end of the war in Europe, plans were afoot to transfer some 10+ Lancaster Sqns out to the Pacific theatre to help with the air campaign against Japan

Andy H

[Aufklarung]

Andy
I think this is perhaps the thread of which you speak.
http://www.thirdreichforum.com/viewtopic.php?t=28674

regards
A

[Andy H]

Thanks Auf

Sure your not in Int Corp

Stag on my friend

Andy H

[Dora]

Vinnie O,
Great description and history of the two British big bombs. In your story of their use by the USAAF, I was wondering if, in addition to not having US aircraft being able to carry them without extensive modification, was the knowledge that the use of such ordanance would soon be unnecessary in light of the atomic weapons soon to be deployed against Japan? Just a thought.
Dora
800mm

[redcoat]

As well, I seem to remember that deep-penetration bombs were used against the Watten Bunker, Eperlecques (a planned-for V-2 assembly and launching site), hitting one corner of the structure.

Here the list of targets hit by Grand Slam bombs

Bielefeld viaduct ( 14/3/45 ) 1 bomb
Arnsberg viaduct ( 15/3/45 ) 1 bomb
Arnsberg viaduct ( 19/3/45 ) 6 bombs
Arbergen bridge ( 21/3/45 ) 2 bombs
Nienburg bridge ( 22/3/45 ) 5 bombs
Bremen bridge ( 23/3/45 ) 5 bombs + 1 jettison
Farge U-Boat shelter ( 27/3/45 ) 12 bombs + 1 jettison
Finkenwerder U-boat shelter ( 9/4/45 ) 2 bombs
Heligoland batteries ( 19/4/45 ) 6 bombs
All were dropped by the one squadron, 617(Dambusters).

The bomb that hit the Watten bunker may have been a Disney bomb (no I'm not kidding )

'Disney' Rocket-Assisted Bomb
Designed by Captain Terrell RN of the UK, this 4,500 lb (2040 kg) hard-case streamlined bomb was intended to be used against U-boat pens and other super-hardened targets.
Dropped from approx 20,000 ft (6096 m) the bomb had a barometric fuze which activated at 5,000 ft (1525 m.) a rocket in the tail of the bomb bringing the impact velocity up to 2,400 ft/sec (730 m/sec.)

Carried only on B-17 bombers in pairs under-wing, this weapon was first used in Febuary 1945, when eighteen Disney bombs were used on the U-boat pens at Ijmuden in Holland, scoring one direct hit. By the end of the war a total of 158 Disney Bombs had been used in combat.