150th Anniversary

Shedding light on our mystery object

Thank you one and all who contributed ideas on the mystery object found earlier this year in the depths of the Civil and Environmental Engineering building.

Many creative and interesting guesses were made. Several guesses came close.

The most popular suggestion was a calibration tool used to set explosives during World War I.

Shrapnel shells were widely used in WWI as anti-personnel weapons, and were particularly effective in the open. “Shrapnel” is a term often misused to indicate fragments of bursting high-explosive shells, but true shrapnel was a shell that burst over or in front of the target, throwing a payload of small balls forward and downward. The shell was detonated by a fuze, which in WWI field artillery was frequently an igniferous time fuze. Time fuzes allowed the shell to burst in the air at a certain time after being fired.

Until the development of electronics such fuzes were set manually with a key or wrench. Our mystery object is a German-made example.

Julian Napper (BE Elec Eng, 1958) and John Nairn (BE Elec Eng, 1960)

Igniferous time fuzes consisted of a powder ring in an inverted ‘U’ metal channel. The shock of firing the shell ignited the powder ring, which would be transferred through a flash hole to the magazine and ignite the bursting charge in the shell. Setting the fuze aligned the flash hole with a time marker on the channel. These fuzes relied on their velocity to be effective, and obviously setting the fuzes manually required great skill – particularly with moving targets, as frequently happened.

Shrapnel shells were gradually superseded as an anti-personnel munition from World War II in favour of high-explosive shells, filled with  explosives in a casing which would also fragment.

Unknown artist, 1938. From Artillery (2nd ed., Military Publishing House of the People's Commissariat of Defense of the USSR.) From Wikimedia Commons

Sources:
http://en.wikipedia.org/wiki/Shrapnel_shell
http://nigelef.tripod.com/ammo.htm
http://www.lovettartillery.com/15cm_sFH_Setter.html

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