EXPLODER DYNAMO MARK VII
These would both have been made to the same standard although 5 years apart.
It was designed to fire through 150-ohms resistance.
The increased current required to fire Detonators Electric No.33 and the commercial equivalent of the time, was 15 detonators through 400 yards (365m) of double lead E.I. Mk II cable.
The exploder weighs 12.5lbs (5.7kg) and has a lift up carrying and firing handle.
The 15 detonators were fired with a 3” length of stroke, with downward pressure increasing towards the end of the stroke. To do this it was essential that the exploder was operated on a firm surface.
The Exploder MkVII was tested using the Box Fusion Test which was set to 100 ohms and if it could fuze the iridio-platinum bridge through that resistance, it was considered that it could fire 15 of the detonators in series through the 400 yards of specified double cable, with that length of stroke.
This was not necessarily the maximum capacity of the exploder, but it was a safe figure and was not be exceeded.
This was the situation by September 1942, but sometime by the end of WWII a modified Exploder Mark VII* was introduced which could fire 40 of the same detonators using the same parameters.
The only general publications of which I am aware are:
Military Engineering, Volume IV, 1934 - Chapters I to VIII inclusive.
Field Engineering Pamphlet No.7 1940.
Military Engineering, Volume IV, Part 1, Demolitions 1942 (Provisional), which superseded the other two, if it was ever produced.
The latter contained so much information about all aspects of demolitions, explosives, sabotage etc. that it would never have been on general issue and would hav.e been held at formation HQs.
Various arms such as military engineers, ammunition technical staff, assault pioneers etc. would have those parts relative to their activities included in their own publications.
These would both have been made to the same standard although 5 years apart.
It was designed to fire through 150-ohms resistance.
The increased current required to fire Detonators Electric No.33 and the commercial equivalent of the time, was 15 detonators through 400 yards (365m) of double lead E.I. Mk II cable.
The exploder weighs 12.5lbs (5.7kg) and has a lift up carrying and firing handle.
The 15 detonators were fired with a 3” length of stroke, with downward pressure increasing towards the end of the stroke. To do this it was essential that the exploder was operated on a firm surface.
The Exploder MkVII was tested using the Box Fusion Test which was set to 100 ohms and if it could fuze the iridio-platinum bridge through that resistance, it was considered that it could fire 15 of the detonators in series through the 400 yards of specified double cable, with that length of stroke.
This was not necessarily the maximum capacity of the exploder, but it was a safe figure and was not be exceeded.
This was the situation by September 1942, but sometime by the end of WWII a modified Exploder Mark VII* was introduced which could fire 40 of the same detonators using the same parameters.
The only general publications of which I am aware are:
Military Engineering, Volume IV, 1934 - Chapters I to VIII inclusive.
Field Engineering Pamphlet No.7 1940.
Military Engineering, Volume IV, Part 1, Demolitions 1942 (Provisional), which superseded the other two, if it was ever produced.
The latter contained so much information about all aspects of demolitions, explosives, sabotage etc. that it would never have been on general issue and would hav.e been held at formation HQs.
Various arms such as military engineers, ammunition technical staff, assault pioneers etc. would have those parts relative to their activities included in their own publications.
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