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"This electromechanical counting machine was designed to eliminate variables at high speed. Its action was described as 'machines that go on ticking until they reach a combination that will cause them to produce an output'; hence bombe." |
Introduction
A mock-up of the Bombe could be viewed in Hut 11A during the late 1990s, but the roof was leaking and it wasn't a particularly suitable place for the rebuild. However, the frame and early motor/gearing was delivered here and the mechanical work continued until about 2002. By then the electrical/wiring side of the project was to commence and the unit was moved to the drier Hut 12. From about 2004 the Bombe was relocated to B Block where it was completed and officially switched on in 2007. The Bombe Rebuild was moved to H Block (TNMoC) in 2018.
It's well worth a trip to go and hear the Bombe ticking and to listen to the story of its construction and use.
| Turing Welchman Bombe | |
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The electrical components are contained on the hinged section, shown here swung out for access. |
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Part of hinged section of relays, resistors and condensers. |
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One end of the unit showing access to more plugs and red wiring. |
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Centre of photo shows oiling tubes. |
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The Bombe Rebuild was transferred from Bletchley B Block to H Block [TNMoC] during April and the new gallery opened in July 2018. |
| Components | |
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Showcase displaying machined parts and jigs which were an essential part of the rebuild method. |
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Wiring and cableform jigs. |
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A test drum. |
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Commutator wiring. |
| Photo Gallery | |
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A selection of photos taken between 2007 and 2015 of the Bombe Unit Hut 11 and the Rebuild in B Block. |
| PETARD | |
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Before the Bombe Rebuild Team made large numbers of mechanical parts, a test assembly needed to be constructed. This covered all the main parts of the machine, but it was only necessary to make four Letchworth Enigmas driven by shortened vertical and horizontal shafts and one carry cam assembly to achieve this. This unit is capable of demonstrating the full Bombe mechanical action albeit at one third speed. The plan is that when resources become available, this unit will be completed with commutators and a lubrication system etc.. Following this power supply will be added and electric and electronic units developed to turn this whole unit into a permanent working demonstration unit. |
The team chose the name Petard because this is another name for a type of small Bomb(e). It is also the name HMS Petard that was instrumental in capturing vital German Enigma material. |
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