Questions about RDX and Torpex

[marty1]

Couple of questions regarding explosives...

1) When did ordnance containing torpex begin seeing service. Was torpex a British invented explosive?

2) When was RDX developed? Was this a British development?

Thanks for any replies.

Best regards
marty_01

[Tiornu]

Yes, Torpex was British. It started into service at the tail end of 1942, made its way across the Atlantic to the US, and became standard in both navies during 1943.

[marty1]

Thnx Tiornu. Any idea when RDX first began being used in military high explosives? Surely Torpex wasn’t the first instance?

[tommy303]

RDX, which is the British acronym for Hexogen was discovered in about 1932 and by 1935 was also being produced in Germany by at least one plant, and during the war by another ten or so. It's early usage was hindered by its expense and its relative instability compared with other explosives such as TNT. It could only be processed in solid form as its melting point too closely conincided with the temperature at which it would detonate. Consequently it was generally powdered and mixed with other, lower melting point explosives to form Torpex, Semtex, Trialene, and various demolition explosives such as Compositions A, B, and C.

In Germany, RDX was used in varying percentages in bomb and shell fillings such as Trialen 105, 106, 107, 108, 109, 110, and 105/109, Amatol39N and N5, Fp40/60, Füllung 89 (RDX and Montan wax), etc. It was also desensitized with wax and used in gaines for shells and bombs under the designations Füllung 91-H5 and 92-H10. In Tritolital, RDX was used with TNT and aluminium powder as a substitute filling in mines, torpedos and depth charges for the more usual SW18, 36, and 39 fillings.

[marty1]

Thanks Tommy.

This is perhaps very obscure -- but I have been looking over Soviet/Red Naval AP projectiles from the mid-1930's up to the end of WWII. I have been unable to find anything reliable from this period regarding bursting charges and their composition. Much of the information I have stems from post war/cold war assessments of Soviet Naval AP. Any idea if the Soviet were using RDX/Hexogen in bursting charges during this period -- i.e. mid-1930's up to the end of WWII?

[tommy303]

RDX is one of those little military secrets which did not remain secret for very long. I am not aware of the exact extent to which the Soviets used RDX, but it was used in a number of smaller calibre AA shells and aircraft cannon, usually mixed with molten TNT which was cast into the shell, or mixed with TNT and wax which was pressed into blocks to fit the shell cavity.

I did a little more research into RDX by the way. It was actually discovered in Germany in the 1890s by Hans Henning, although its explosive properties were not recognized until the 1920s. In about 1932 it was given the designation RDX (Research and Development eXplosive or X for unknown catalog number depending on the story you read). It was, however expensive to make until about 1940 when the British found a way to synthesize its production. Aside from its sensitivity, it was also dangerously toxic, aggrevated by its being processed only as a powder (which makes me glad that its discoveror, Henning, was not my physcian since he offered it as a medicine).

Getting back to Soviet usage of RDX, their major calibre shells appear not to have used it neither as a constituent of the main charge nor as a part of the gaine. Instead, fillers appear to have been cast TNT for major shells and cast TNT desensitized with wax for major AP shells. Nor do the Soviets appear to have used it mines, torpedos or depth charges, preferring instead to mix TNT with Tetryl powder or as the Germans did, TNT mixed with hexanitrodiphenylamine.

hope this helps a bit.

thomas

[tommy303]

To clarify my above statement, RDX is the British name for hexogen, while Cyclonite is the name the popular name the Germans assigned to it. For secrecy purposes, so that production facilities were more difficult to identify, it was given the military designation Füllung 104.

[marty1]

Hi Tommy:

Yes, I have also seen references to the medicinal use of Cyclonite. Perhaps it was something like taking nitroglycerin for a heart condition. Better health through the practical application of explosives.

Do you have any thoughts on Soviet use of Amatol during this period? Did they have good supplies of TNT during WWII, or were they cutting it with ammonium nitrate?

Thnx again for your input. I realize this is a rather obscure topic.

[tommy303]

I would imagine that the big savings Amatol would have made would have been in saving high quality alloy steel rather than saving TNT. High quality alloy steels were better used in armour plate production and for AP shot and shell. There is little reason to presume the Soviets were short of TNT or like quality explosives. Low quality steel shells actually fragment better with Amatol 60/40 for instance then they do with straight TNT. Essentially the ammonium nitrate lowers the brisance factor of the TNT allowing the charge to rend the shell into usable fragments with adequate coverage of an area and adequate lethal radius. A straight TNT charge could easily blow a low or poor quality shell into a cloud of tiny fragments which might not have sufficient weight to carry out to the hoped for lethal radius. Its a matter of matching the explosive to the steel of the shell--stronger allow shells require stronger explosives--low quality cast steel shells need lower powered explosives.

I am sure the Russians used Amatol to a degree, but to exactly what an extent I would only be guessing.