Bouncing bomb

Infobox Weapon
name = Vickers Type 464
code name: Upkeep store


caption = Upkeep bouncing bomb at the Imperial War Museum Duxford
origin = UK
type = Conventional (depth charge)
is_ranged =yes
is_bladed=
is_explosive =yes
is_artillery=
is_vehicle=
is_UK =yes
service = May 16/17 May 1943
(Operation Chastise)cite web|last=|first=|url=http://www.raf.mod.uk/bombercommand/may43.html|format=html |title=Campaign Diary|work=Royal Air Force Bomber Command 60th Anniversary|accessdate=2007-05-24|publisher=UK Crown]
used_by = No. 617 Squadron RAF
wars = World War II
designer = Barnes Wallis
design_date = April 1942
manufacturer = Vickers-Armstrongscite web|last=Field|first=Brian|url=http://www.bbc.co.uk/ww2peopleswar/stories/27/a2163827.shtml|format=html |title=Dambuster Bomb Development|work=WW2 People's War|accessdate=2008-02-21|publisher=bbc.co.uk]
production_date = February 1943
number = 19
variants = Highball spherical bouncing bomb, concrete training bombs
weight = 4195 kg (9,250 pounds)cite web|last=|first=|url=http://www.thedambusters.org.uk/upkeep.html|format=html |title=Upkeep: The Bouncing Bomb |work=The Dambusters (617 Squadron) |accessdate=2008-02-21|publisher=thedambusters.org.uk]
length = 60 inches (152 cm)
part_length=
width =56 inches (142 cm )
height =
crew =
cartridge=
caliber=
action=
rate = 500 rpm backward spinNOTE: In addition to slowing the bomb on each successive bounce so it would trail "behind" the aircraft (for safety), the backward spin increased the relative speed of the surface of the bomb against the surface of the water, allowing the bomb to skip at lower airspeeds. The prolate spinning also helped to keep the bomb horizontal during the skip trajectory (in a different manner than the flat oblate spin of a skipped rock.)]
velocity = 240-250 mph (386-402 km/h)
range = 400-500 yards (365-457 m)
max_range=
feed=
sights =
diameter =
filling = Torpex
filling_weight = 6,600 pounds (2,990 kg)
detonation = hydrostatic fuze (depth of 30 ft),cite web|last=Moorcraft|first=Lucy|url=http://www.chm.bris.ac.uk/webprojects2001/moorcraft/The%20Bouncing%20Bomb.htm|format=html |title=The Bouncing Bomb|work=The Dambusters|accessdate=2008-02-21|publisher=University of Bristol] with backup chemical time fuze.
yield=

A bouncing bomb is a bomb designed specifically to bounce to a target such as across water to avoid torpedo nets. Unlike skip bombing, [In the 1600s, Vauban had finalized the use of bouncing artillery shells for attacking forts.Fact|date=July 2007 In the nineteenth century, the Royal Navy had observed that cannonballs had increased range when they bounced on water.] which uses conventional bombs as during the March 1943 Battle of the Bismarck Sea, the British, Germans, and Soviets developed World War II bombs specifically for bouncing to targets and then exploding. The inventor of this technique was the British engineer Barnes Wallis. His Upkeep bouncing bomb was used in the May 1943 British Operation Chastise to bounce into dams and explode underwater with similar effect to the underground detonation of the earth quake bomb (e.g., Grand Slam bomb and Tallboy bomb), which he also invented.

British bouncing bomb

Barnes Wallis' April 1942 paper Spherical Bomb — Surface Torpedo described the attack on a battleship by bouncing a weapon on the surface of the water, striking the ship, and then dropping to explode at a depth where the hull is less protected. The initial spherical design with dimples codenamed Highball was developed to be dropped from a modified de Havilland Mosquito that could carry two of the bombs. The mechanical differential analyzer analogue computer used during design is preserved in New Zealand at MOTAT.Fact|date=July 2007 In September 1942, full-scale test drops of the spherical design began at Chesil Beach using a modified Vickers Wellington.cite web|last=Murray|first=Iain|url=http://www.computing.dundee.ac.uk/staff/irmurray/bigbounc.asp|title=Big & Bouncy - the special weapons of Sir Barnes Wallis|work=|accessdate=2008-02-21|publisher=University of Dundee] At the start of 1943, Wallis' paper Air Attack on Dams reporting the results of scale model experiments and aircraft drops. [cite web|last=|first=|url=http://www.war-experience.org/history/keyaspects/damsraid0543/default.asp|title=The Second World War Experience Centre - The Dams Raid May 1943|work=|accessdate=2008-02-21|publisher=]

Upkeep bouncing bomb

The operational British bouncing bomb was officially code named Upkeep storeFact|date=July 2007 and was known by the manufacturers as Vickers Type 464. The cylindrical bomb used Torpex ("torpedo explosive") to provide a longer explosive pulse for greater effect against underwater targets. Testing of the bouncing bomb was done at Reculver, Kent. During this time, Barnes Wallis lived at the Mill House, Chislet.The Times, 20 October 2005] In May 1943, Operation Chastise attacked dams in Germany's Ruhr Valley -- two were breached "with limited effect". [cite web|last=|first=|url=http://www.usaaf.net/surveys/eto/ebs14.htm|format=html |title=Secondary Campaigns|work=United States Strategic Bombing Survey, Summary Report (European War)|accessdate=2008-02-21|publisher=|date=1945-09-30|quote= The breaking of the Mohne and the Eder dams, though the cost was small, also had limited effect.] The British losses during the operation prompted the project to be discontinuedFact|date=July 2007 and, in January 1974 under Britain's "thirty year rule", the files for both Upkeep and Highball (along with Ultra files) were released.
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thumb|right|Animation_of_a_bouncing_bomb_path_over_torpedo nets into a dam]

urviving bombs

All combat Upkeep bombs were disposed of at the end of hostilities.Fact|date=July 2007 However, concrete-filled bombs used in test and training drops at Reculver, Kent have been recovered and are displayed at various sites:
* Dover Castle.
* Imperial War Museum Duxford
* Brookland's Museum in Weybridge
* Herne Bay Museum and Gallery.
* Brenzett Aeronautical Museum on Romney Marsh.
* Spitfire & Hurricane Museum at RAF Manston, Kent.
* Lincolnshire Aviation Heritage Centre, East Kirkby.
* Haverfordwest Aerodrome displays a section of a Highball bomb
* Abbotsbury Swannery displays a section of a Highball bomb
* RAF Lossiemouth - only accessible to the public with prior permission.
* "The Petwood Hotel" museum, Woodhall Spa, Lincolnshire, displays a damaged Upkeep bomb.
* Eden Camp Museum North Yorkshire
* Yorkshire Air Museum Elvington, North Yorkshire

German bouncing bomb

The Germans recovered an unexploded Operation Chastise bomb in some woods and a 385 kg (850 pound) version of the bouncing bomb was tested by the Luftwaffe. Designed for use against British shipping, the German bouncing bomb was code named Kurt and built at the Luftwaffe Experimental Centre in Travemünde. However, without backspin the dropped bomb matched the speed of the Focke-Wulf Fw 190 during trials. Booster rockets failed to rectify the problem and the project was discontinued in 1944. [Sweetman, John. "The Dambusters Raid". London: Cassell, 1999. ISBN 0-304-35173-3]

oviet bouncing bomb

The Soviets are reputed to have used two bouncing bombs during the attack that sunk the World War II German anti-aircraft cruiser Niobe in Kotka, Finland on 16 July 1944.Fact|date=November 2007. No development details are known for this device, and it may have been a skip bombing incident.

External links

* [http://youtube.com/watch?v=5JqBiMgC2Wg&feature=related Test film of both Upkeep and Highball] bouncing bombs including US A-26 Invader test drops
* [http://www.1001crash.com/index-page-bomb-lg-2.html The bouncing bombs] - History, pictures and videos.

References and Notes