Tallboy bomb
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| Tallboy bomb | |
|---|---|
 Modern replica of a Tallboy |
|
| Type | Conventional |
| Place of origin | United Kingdom |
| Service history | |
| In service | June 8, 1944 - April 25, 1945 |
| Used by | No. 617 Squadron RAF |
| Wars | World War II |
| Production history | |
| Designer | Barnes Wallis |
| Manufacturer | Vickers |
| Number built | 854[1] |
| Specifications | |
| Weight | 5,443 kg (12,000 lb) |
| Length | 6.35 m (21 ft) |
| Diameter | 950 mm (38 in) |
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| Filling | Torpex D1 |
| Filling weight | 2,358 kg (5,200 lb) |
| Detonation mechanism |
No. 58 fuse - built from No. 30 Pistol (impact detonation) - or No. 47 time delay fuze |
The Tallboy was an earth quake bomb developed by Barnes Wallis and brought into operation by the British in 1944. It weighed five tons and, carried by the Avro Lancaster bomber, was effective against concrete structures against which earlier, smaller bombs had proved ineffective.
Contents |
[edit] History
The British aeronautical engineer Barnes 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 transmitted through the ground are less attenuated than through air. Barnes Wallis designed the "Victory Bomber" of 50 tons which would fly at 320 mph (510 km/h) at 45,000 feet (14,000 m) to carry the heavy bomb over 4,000 miles (6,400 km), but the Air Ministry were against a single-bomb bomber and the idea was not pursued beyond 1942. Following Wallis's 1942 paper Spherical Bomb — Surface Torpedo and the design of the "bouncing bomb" for the Dam Busters of Operation Chastise, the actual design and production of Tallboy was done without a contract on the initiative of a single official within the Ministry. As such the RAF were using bombs they had not bought and which were actually still the property of the manufacturers; Vickers. This situation was regularized once their capabilities were recognised.
Amongst many spectacular accomplishments by the Tallboy, the June 24, 1944 Operation Crossbow attack on the La Coupole (along with Grand Slam bombing) undermined the foundations. A Tallboy of the June 8/9, 1944 Saumur tunnel attack passed straight through the hill and exploded right inside the tunnel 60 feet (18 m) below the surface.[2]
[edit] Design
Most large Allied World War II aircraft bombs had very thin skins to maximize the weight of explosive which a bomber could carry—this was an improvement on the early part of the war when the actual HE content of British bomb designs was low. To be able to penetrate the earth (or hardened targets) without breaking apart, the casing of the Tallboy had to be strong. Each was cast in one piece of high tensile steel that would enable it to survive the impact before detonation. At the same time to achieve the penetration required, Wallis designed the Tallboy to be very aerodynamic so that when dropped from a great height it would reach a velocity higher than traditional bomb designs. In the final design the tail of the bomb was about half the overall length of the finished weapon—the bomb casing was some 10 feet (3 m) of the overall 21-foot (6 m) length. Initially the bomb had a tendency to tumble, so the tail was modified—the fins were given a slight twist so that the bomb spun as it fell. The gyroscopic effect thus generated stopped the pitching and yawing, improved the aerodynamics and improved accuracy. The improved design worked so well that it was found in development that it passed through the sound barrier as it fell.[citation needed] When dropped from 20,000 ft (6,100 m) it made a crater 80 feet deep (24 m) and 100 feet (30 m) across and could go through 16 feet (5 m) of concrete.[1]
W. J. Lawrence wrote about the Tallboy bomb in his book, No 5 Bomber Group:[3]
"It was an extraordinary weapon, an apparent contradiction in terms, since it had at one and the same time the explosive force of a large high-capacity blast bomb and the penetrating power of an armour-piercing bomb. On the ground it was capable of displacing a million cubic feet (29,000 m³) of earth and made a crater which it would have taken 5,000 tons of earth to fill. It was ballistically perfect and in consequence had a very high terminal velocity, variously estimated at 3,600 and 3,700 feet (1,100 m) per second (1,100–1,130 m/s or about 2,500 mph / 4,000 km/h), which was, of course, a good deal faster than sound so that, as with the V-2 rocket, the noise of its fall would be heard after that of the explosion."
The weight of the Tallboy (approximately 12,000 lb) and the high altitude required of the bombing aircraft meant that the Lancaster bombers used had to be specially adapted. Armour plating and even defensive armament were removed to reduce weight and the bomb-bay doors had to be adapted. Even then the Lancaster was not capable of reaching the bomb's intended dropping height of 40,000 ft (12,200 m) but only around 25,000 (7,700 m). At the same time No. 617 "Dambusters" Squadron trained in the use of a special bombsight the Stabilizing Automatic Bomb Sight (SABS). For accuracy multiple corrections had to be made for temperature, wind speed, etc. However it was only effective if the target could be identified and several missions were canceled or unsuccessful because of difficulty in accurately identifying and marking the targets.
Each bomb was a precision-built instrument of war made from expensive materials and carefully finished. They were not considered expendable and if not used on a raid were to be brought back to base rather than safely dropped in the sea.[4] The value of the weapon offset the additional risk to the aircrew.
The Tallboy was used to attack strategic targets that could not be destroyed by other means. When it was found that the Lancaster could be modified to carry a bomb larger than the Tallboy, Wallis produced the even larger Grand Slam bomb.
For use on underground targets, the bomb was fitted with three inertia pistols. These operated a detonator with a 28 second delay which allowed time for the bomb to penetrate to design depth before exploding. Three fuses were always used in order to guarantee detonation.
[edit] Tallboy operations
[edit] June - August 1944
- Saumur rail tunnel — The sole operational north-south route on the Loire. Nineteen Tallboy equipped, and six conventionally equipped Lancasters of No. 617 Squadron, attacked on the night of 8/9 June 1944. This was the first use of the Tallboy bomb and the line was destroyed — one Tallboy bored through the hillside and exploded in the tunnel about 60 ft (18 m) below, completely blocking it. No aircraft were lost during the raid.[2]
[edit] Operation Crossbow sorties
Operation Crossbow was a set of offensive and defensive measures that were carried out to deal with the threat of German V-1 and V-2 rocket weaponry. As part of the operation, a number of bombing sorties that carried Tallboy bombs were deployed by the British to bomb and destroy a number of missile sites.
- Éperlecques, June 19, 1944
- The nearest Tallboy by No. 617 Squadron landed 50 yards (46 m) from the target[4]
- Wizernes, June 24, 1944
- Several Tallboy hits undermined the foundations but did not penetrate the dome.[4]
- Saint-Leu-d'Esserent, July 4, 1944
- 17 Lancasters, 1 Mosquito and 1 Mustang of No 617 Squadron used Tallboys in an attempt to collapse the limestone roof of the caves. No 5 Group follows with 1,000 lb (450 kg) bombs.[4][5][6]
- Mimoyecques July 6, 1944
- Tallboys hit one of the V-3 cannon's shafts and block galleries with earth and debris[7][5][4]
- Wizernes, July 17, 1944
- 16 Lancasters, 1 Mosquito and a new P-51 Mustang bomb Wizernes -- 3 Lancasters managed to drop Tallboys (one caused the dome to shift out of alignment, two others blocked the entrance.[8]
- Rilly La Montage, July 24, 1944
- Both ends of the railway tunnel were collapsed by Tallboy bombs dropped by No. 617 Squadron.[4] William Reid's Lancaster at 12,000 ft (3,700 m) was hit by a Tallboy dropped from 18,000 ft (5,500 m)[9]
- Éperlecques, July 27, 1944
- One Tallboy hit the target but did not penetrate the structure.[10]
[edit] Sorties against German dockyards
Shipping in the English Channel and the Atlantic Ocean were threatened by U-boats and E-boats stationed in France. U-boat docks were protected against conventional aerial bombardment by thick concrete roofs.
- Le Havre, June 14, 1944
- Part of the first massive RAF daylight raid since the end of May 1943, two waves attacked E-boat facilities at Le Havre: No 1 Group first, No 3 Group second. Just before the first wave, 22 Lancasters of 617 Squadron and 3 Mosquito marker aircraft attacked, with several hits on the pens and one bomb penetrated the roof.[4]
- Boulogne harbour, June 15, 1944
- 297 aircraft - 155 Lancasters, 130 Halifaxes, 12 Mosquitos - of Nos 1, 4, 5, 6 and 8 Groups attacked Boulogne harbour. 1 Halifax was lost. A French report described the great destruction as the worst raid on Boulogne.[4][citation needed][11]
- Brest, August 5, 1944
- 15 Lancasters of No. 617 Squadron attacked the U-boat pens at Brest and scored 6 direct hits with Tallboys penetrating the concrete roofs. 1 Lancaster shot down by flak. Subsequent attempts to reinforce other sites with even thicker concrete diverted resources from other projects.[4]
- La pallice, August 8, 1944
- Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.[12]
[edit] September - November 1944
- Dortmund-Ems Canal near Ladbergen, north of Münster – No. 617 Squadron scored six direct hits with Tallboys on night September 23/24 1944.[4]
- Kembs Dam north of Basle — The dam waters could have been kept in reserve to flood the area of a US advance. On 7 October 1944, the Dambusters destroyed the lock gates with Tallboys dropped at low level releasing the stored water.[4]
- Sorpe Dam — This target of the original Dambusters raid survived a second attack by 9 Squadron on 15 October 1944 (617 Squadron did not participate in this raid). The Tallboy bombs were seen to hit the dam but did not breach it.[4]
[edit] Bombing sorties against Tirpitz
The German battleship Tirpitz was a threat against convoys sailing to and from the Soviet Union.
- Operation Paravane, September 15, 1944
- One Tallboy hit near the bow of the Tirpitz and caused considerable damage. The bombing shock from the operation damaged the battleships engines, and the Germans converted the ship for use as a semi-static heavy artillery battery.[4]
- Operation Obviate, October 29, 1944
- No direct hits were scored during but one near miss bent a propeller shaft of Tirpitz.[4]
- Operation Catechism, November 12, 1944
- In the final operation the Tirpitz was sunk when at least two Tallboys[13] hit and capsized the battleship.[4]
[edit] December 1944 - April 1945
- Bombing of U-boat pens, December 1944-April 1945
- Flight Lieutenant Thomas Clifford Iveson dropped one Tallboy.[12]
- IJmuiden, January 12, 1945
- 32 Lancasters and 1 Mosquito of Nos 9 and 617 Squadrons attacked U-boat pens and shipping in Bergen harbour. 3 Lancasters of No 617 Squadron and 1 from No 9 Squadron were lost; the Germans told the local people that 11 bombers had been shot down. A local report says that 3 Tallboys penetrated the 3½-metre-thick roof of the pens and caused severe damage to workshops, offices and stores inside.[4][12]
- IJmuiden & Poortershaven February 3, 1945
- 36 Lancasters of No 5 Group attacked U-boat pens at IJmuiden (No 9 Squadron) and Poortershaven (No 617 Squadron) with Tallboy bombs. Hits were claimed at both targets without loss.[4]
- No. 617 Squadron attacked with Tallboys and Grand Slam bombs.[citation needed] Some of the bombs hit their target and no aircraft were lost.[4]
- 969 aircraft - 617 Avro Lancasters, 332 Handley Page Halifaxes, 20 de Havilland Mosquitos of all groups - successfully used Tallboys to bomb the Naval base, airfield, and town into crater-pitted moonscapes. Three Halifaxes were lost,[4] and the islands were evacuated the following night.
The Urft Dam, (30 miles south west of Cologne) was attacked on 8 December and 11 December 1944 to prevent it being used to flood the area below as American troops advanced. The lip of the dam was damaged, but the Germans prevented further damage by lowering the water level.[14][15]
Politz was attacked by No. 617 21 December 1944[citation needed][16]
The Bielefeld and Arnsberg viaducts were attacked by No. 617 and No. 9 squadrons with Tallboys and the first Grand Slam bomb on 14 March 1945. The Arnsberg viaduct withstood the attack but 100 m of the Bielefeld viaduct collapsed through the 'earthquake effect' of the Grand Slam and Tallboys.[4] The Arnsberg viaduct was attacked again on 15 March 1945 by No. 9 Squadron it did not collapse.[4]
The Pocket battleship Lützow was attacked on 16 April 1945 by No. 617 Squadron. Despite intense flak, 15 aircraft managed to bomb the target with Tallboys or with 1,000-pounders. One near miss with a Tallboy tore a large hole in the bottom of the Lützow and she settled to the bottom in shallow water. One Lancaster was shot down, the Squadron's last loss in the war.[4]
Hitler's vacation home, Berghof, near Berchtesgaden was attacked on 25 April 1945 with a mixed force which included 6 Lancasters of No. 617 Squadron dropping their last Tallboys. The bombing appeared to be accurate and effective.[4]
[edit] See also
[edit] Notes and references
- ^ a b Bombs Weapons Rockets Aircraft Ordnance
- ^ a b Saumer Tunnel, 9th June 1944. Royal Air Force Bomber Command 60th Anniversary. Retrieved on 2007-05-24.
- ^ Spartacus: Tallboy
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y Campaign Diary. Royal Air Force Bomber Command 60th Anniversary. UK Crown. Retrieved on 2007-05-24. 1944: June, July, August, September, October, November, December 1945: January, February, March, April
- ^ a b Irving, David (1964). The Mare's Nest. London: William Kimber and Co, p245.
- ^ Collier, Basil [1964] (1976). The Battle of the V-Weapons, 1944-1945. Yorkshire: The Emfield Press, p68,84. ISBN 0 7057 0070 4.
- ^ Brickhill, Paul (1951). The Dam-busters, Apogee Books Space Series 36. New York: Thomas Y. Crowell. ISBN 0-330-37644-6.
- ^ Dambusters - The raid on Wizernes Rocket Base
- ^ Flight Lieutenant William Reid VC. News. Telegraph Media Group Limited 2008 (November 29, 2001). Retrieved on 2008-02-17.
- ^ World War II German hardened A4/V2 rocket launch sites. Retrieved on 2008-02-17.
- ^ The reference for Boulogne does not indicate Tallboy bombs were used.
- ^ a b c d e f g Keable, Jim. Flight Lieutenant Thomas Clifford Iveson (html). AeroVenture News. AeroVenture. Retrieved on 2008-02-24.
- ^ Tirpitz, November 12 1944. Royal Air Force Bomber Command 60th Anniversary. UK Crown. Retrieved on 2007-05-24.
- ^ 617 Squadeon - The Operational Record Book 1943 - 1945 (pdf) with additional information by Tobin Jones; Binx Publishing, Pevensey House, Sheep Street, Bicester. OX26 6JF. Acknowledgement is given to HMSO as holders of the copyright on the Operational Record Book. Page 507
- ^ Iain Murray [Big & Bouncy: The Special Weapons of Barnes Wallis], 2005. Quotes Alan W. Cooper; From the Dams to the Tirpitz, 1982 (Goodall), and Alan W. Cooper; The Men Who Breached the Dams, 1982 (Kimber)
- ^ Memorabilia signing and veterans day at Lincolnshire Aviation Heritage Centre East Kirkby South Yorkshire Aircraft Museum 29 August 2005] See Flight Lieutenant Thomas Clifford Iveson. The Campaign Diary does not indicate Tallboy bombs were used on this Politz mission.
[edit] External links
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