Tallboy (bomb)

Tallboy
RAF ground crew handling the Tallboy that was later dropped on the V Weapon site at Wizernes, France, 1944
Type	Earthquake bomb
Place of origin	United Kingdom
Service history
In service	8 June 1944 – 25 April 1945
Used by	No. 9 Squadron RAF, No. 617 Squadron RAF
Wars	World War II
Production history
Designer	Barnes Wallis
Manufacturer	Vickers
No. built	854
Specifications
Weight	12,000 lb (5,400 kg)
Length	21 ft (6.4 m)
Diameter	38 in (97 cm)
Filling	Torpex D1
Filling weight	5,200 lb (2,400 kg)
Detonation mechanism	No. 58 fuse, built from No. 30 Pistol (impact detonation); or No. 47 time delay fuse. Fuses were inserted into tetryl boosters located in the rear of the casing.

External image

Bomb damage at Mimoyecques V-Weapon Site

Tallboy, or Bomb, Medium Capacity, 12,000 lb, was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis and deployed by the RAF in 1944, at five long tons and carried by the Avro Lancaster. It was effective against hardened structures against which prior, smaller bombs had proved ineffective.

Wallis presented his ideas for a 10-ton bomb in his 1941 paper A Note on a Method of Attacking the Axis Powers, which showed that a very large bomb exploding deep underground next to a target would transmit the shock into the foundations of the target, particularly since shock waves are transmitted through the ground more strongly than through air.

Wallis designed the "Victory Bomber" of 50 tons, which would fly at 320 mph (510 km/h) at 45,000 ft (14,000 m) to carry the heavy bomb over 4,000 mi (6,400 km), but the Air Ministry opposed a single-bomb aircraft, and the idea was not pursued after 1942.

The design and production of Tallboy was done without a contract on the initiative of the Ministry, following Wallis' 1942 paper Spherical Bomb—Surface Torpedo and the design of the "bouncing bomb" for the Dam Busters of Operation Chastise. As such, the RAF used bombs that they had not bought and which were still the property of Vickers the manufacturer. This situation was normalised once their capabilities were recognised.

Accomplishments of the Tallboy included the 24 June 1944 Operation Crossbow attack on La Coupole—along with Grand Slams—which undermined the foundations of the V-2 assembly bunker; and a Tallboy attack on the Saumur tunnel on 8–9 June 1944, when bombs passed straight through the hill and exploded inside the tunnel 60 ft (18 m) below the surface.

The last of the Kriegsmarine's Bismarck-class battleships, the Tirpitz, was sunk by an air attack using Tallboys.