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BLU-43 B or BLU-44 A/B “Dragontooth"

pzgr40

Well-Known Member
Premium Member
Cutaway model of a US designed and manufactured BLU-43 B or BLU-44 A/B (Bomb Live Unit) “Dragontooth”, a cluster mine (also called minelet) as used extensively in the Vietnam war during operation “Igloo White” (1970) , a program to prevent infiltration of NVA and Vietcong personel into the southern part of Vietnam.
The mine is a hydraulicly activated air dropped dispenser mine. Due to it’s shape –borrowed from nature’s earonautical design of a maple seed- it does not need a parachute, it will descend to the ground rotating on it’s wing, minimalizing the impact force.
120 Dragontooth mines were packed in a CDU-2/B Cluster adepter, forty of which were loaded into a SUU-13/A dispenser (remains on plane, dispensing cluster adepters), meaning one dispenser holds 4800 mines to form the CBU (Cluster Bomb Unit) 28/A cluster munitions.

Functioning of the mine:
The mine exists of a plastic body, in which an aluminium fuze body with two radial slots is placed. A spring loaded piston with a sleeve is placed in the fuze body which is kept in upper postion by the arming piston retainer (1). The piston also acts as a sort of valve, keeping the liquid sensitizer fluid –Propylenediamine/Methanol- (B) apart from the main charge of 9 grams Nitromethane/ Nitroethane (A) by means of two O-rings. The spring loaded firing pin is kept in backward position by two balls which are kept in inward position by the release sleeve surrounding the firing pin housing (green). Connected to this sleeve is an aluminium cup in which the duplex detonator is placed. A spring keeps this assembly in it’s forward position. A rubber O-ring around the detonator and the inside of the piston sleeve prevents the fluid (B) from leaking away. A sterilizer capsule (C ) is placed in the mine body. This exists of an aluminium cup with a spring loaded sterilisation tablet, kept in place by a disolvable cover.

After release from the CDU-2/B Cluster adepter, the arming tab is released (03), enabeling the arming piston retainer (01) to fall out. This enables the spring to move the piston with the sleeve downward, thereby enabeling the sensitizer fluid (B) to mix with the main charge fluid (A) to form the explosive mix. The fuze and the main charge now form one space filled with liquid. If pressure is applied to the mine body, the hydraulic pressure will push down the aluminium cup with the duplex detonator and the connnected release sleeve, riding it’s spring downward. This enables the two balls to move outward and release the firing pin, exploding the mine.
The mixing of fluids A & B also enables the sensitizer fluid (A) to start to dissolve the dissolvable cover of the sterilisation tablet. If after activation of the mine it is not stepped upon after a certain time, the spring will push the sterilisation tablet (C ) through the weakened dissolvable cover, forming a chemical self- neutralisation system. However, this does not render inert the duplex detonator.

The main difference between the BLU-43B and BLU-44B is in the chemical proces of neutralisation.
The mine weighs 90 grams.
The mine is activated if 7 kg of pressure is applied.
The mine can be found in the colours olive drab, tan, brown, camouflaged or white. An inert Dummy model of the mine is also available.
The transport safety (02) was removed only after the mine was loaded into the CDU-2/B Cluster adepter.

The BLU-44 A/B (self destruct) has a nominal life of 84 hours (3,5 days), and self destructs between 14 and 35 days. The self destruct (neutralisation) capsule of the BLU 44A/B contains Cuprous Chloride and Sodium Borohydride. The Sodium Borohydridereacts with the Methanol and water in the explosive to produce hydrogen gas. The hydrogen gas creates sufficient internal hydraulic pressure to function the fuze.If the mine fails to self destruct, hydraulic pressure will rupture the mine housing or force the hydrogen gas or the explosive mixture out through a small hole (flaw) in the mine. If the explosive mixture remains in the mine , sterilisation will be affected by the cuprous chloride.

The Sowjet union made a copy of this BLU mine, the PFM-1. However this mine is larger than the BLU-43B or`` BLU-44 A/B.

Regards, DJH
 

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Hallo DJH,
really nice work, like always. Thank you. About 45 years have passed since the inception of this mine. Also Millions must have been scattered all over South-East-Asia, I never read anything about this mine, at the time, also the Vietnam war was the last war, with reasonably free press-access. When the russian PFM-1 appeared in Afghanistan in the 80s, western newspapers were full with reports about this dastardly maimer of children. According to the reports, this was a russian invention. In the 90s many models, drawings, dummies of the PFM-1 appeared on the markets. But, only a few years back I found a drawing of the "Dragon Tooth" mine fuze on Wikipedia. By the way, do you know what type of plastic is used as bodymaterial for this mine ? "Myrol" is a very good solvent for many plastics, so you could not use those that would react with "Myrol". Another thing I don't fully understand. What is the reason for the red plastic insert, in between the arms of the safety-tong ? Is this what you call the arming-piston-retainer ? You call this tong-shaped sheet-metal part "arming tab". What action makes this fall off after release from its container ? Always admiring your beautiful work, I remain with kind regards,
Bellifortis.
 
Hi Bellifortis, thanks for your reply.
As youcan see in the drawing , the arming tab (in Dutch: transport veiligheid) has to be pinched together to be removed. to prevent this from happening accidentaly, the red pvc cilinder is placed inbetween. So first one has to renove (push out) the red cilinder, than the tab can be removed.
I suppose the mine is made of PVC (Polyvinylchloride), the most common of plastics.

Regards, DJH
 
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