mortar shellfitted with an M734 Fuze]
The M734 Multioption Fuze for
mortar shells uses frequency modulated continuous wave (FMCW) directional doppler ranging (DDR) techniques and is hardened against electronic countermeasuresdesigned to prematurely trigger detonation. Electrical power is supplied to the fuze via an air flow driven turbine alternator.
The M734 fuze is used on 60 mm, 81 mm, and 120 mm mortar
projectiles. The updated version is the M734A1.
The fuze has three safety/arming mechanisms: initial arming is via
setback(>395 gs), accompanied by a velocitychange of 70 fps sustained airflow to the turbine alternator for a minimum of 100 metres, coupled with apex detection for delayed electrical arming [http://www.l-3com.com/products-services/docoutput.aspx?id=688] .
Tools are not required to arm, disarm or configure the M734 fuze. There is no pull-wire safety pin to remove, unlike some other mortar fuzes. The M734 can be adjusted simply by rotating the top of the fuze
clockwiseby hand until the required 3-letter setting is over the index line. Additionally, the detonation setting can be changed any number of times before firing, without causing damage to the fuze.
There are four sets of 3-letter codes engraved around the
circumferenceof an M734 fuze which have the following meanings:
#PRX - proximity
air burstbetween 1 and 4 metres(3 to 14 feet) above the target
#NSB - near surface-burst between 0 and 1 metre (0 to 3 feet) above the target
#IMP - impact i.e. instantaneous
detonationupon hitting the target
#DLY - delayed detonation, 0.05 seconds after impact
Note: the PRX setting will
detonatea 60/81mm mortar shell at a height of 7 feet, and a 120mm shell at a height of 14 feet above the target.
Reliability is increased by the fact that if the M734 fails to detonate the mortar shell at one setting, it will automatically use the next one along i.e. failure at the PRX setting causes NSB detonation to be selected. Similarly, failure to detonate at the NSB setting would automatically cause IMP to be selected, and so on.
* [http://www.kdi-ppi.com/html/m734_bio.htm The M734A1 fuze]
* [http://www.globalsecurity.org/military/library/policy/army/fm/23-90/ch3.htm Mortar strategy (includes M734)]
* [http://proceedings.ndia.org/5560/Wednesday/Session_III-B/Mohan.pdf M734 improvement project information]
* [http://www.l-3com.com/products-services/docoutput.aspx?id=688 Manufacturer's technical specifications for the M734]
* [http://www.l-3com.com/divisions/overview.aspx?id=43 KDI Precision Products Inc (manufacturer of the M734)]
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