SADARS

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2 June 2016 - The World War Two Proximity Fuze by Brian Hawes

Posted: 03 Jun 2016 02:54 AM PDT
http://www.sadars.co.uk/archives/1260


A good turn out heard Brian explain the need for a WW2 system to achieve
greater accuracy in the Anti-aircraft systems. The equipment needed to
track a moving aircraft was complicated by the typical shell time of ten to
twenty seconds and the need to predict the movement of the target.

By 1940 various systems such as photo sensors, electrostatic or magnetic
field sensors were tried buy found wanting. Fortunately, Three British men,
Butement, Shire and Thomson of The Air Defence Experimental Establishment
suggested a CW oscillator in the shell with a circuit that would measure
the Doppler effect of a reflected signal from the target and trigger the
explosive shell.

However, Britain did not have the resources to produce the fuze in
sufficient numbers and the decision was taken to send the design to the USA
as part of the Tizard Mission since the USA had the industrial resources to
exploit the military potential of the British research.

The system was used with very little modification and in combination with
the SCR 584 ten centimetre tracking radar was considered the most important
development in WW2 after the Atom Bomb.

Photo by Brian Hawes of the Proximity Fuze