Editing Torpex

{{Short description|High explosive}}

[[File:Royal_Air_Force_Bomber_Command,_1942-1945._CH15363.jpg|thumb|[[Tallboy bomb]] stencilled with its explosive filling]]
'''Torpex''' ("Torpedo explosive") is a [[Explosive#Secondary|secondary explosive]], 50% more powerful than [[Trinitrotoluene|TNT]] by mass.{{sfn|Gannon|1996|p=184}} Torpex comprises 42% [[RDX]], 40% TNT and 18% [[Powder (substance)|powdered]] [[aluminium]].<ref name="Türker">{{cite journal |last1=Türker |first1=Lemi |last2=Variş |first2=Serhat |title=Structurally modified RDX - A DFT study |journal=Defence Technology |publisher=Elsevier BV |volume=13 |issue=6 |year=2017 |issn=2214-9147 |doi=10.1016/j.dt.2017.02.002 |pages=385–391|s2cid=99529511 |doi-access=free |hdl=11511/51361 |hdl-access=free }}</ref> It was used in the [[Second World War]] from late 1942, at which time some used the names Torpex and RDX interchangeably. Torpex proved to be particularly useful in underwater munitions because the aluminium component made the explosive pulse last longer, which increased the destructive power. Besides torpedoes, [[naval mine]]s, and [[depth charge]]s, Torpex was also used in the M.C 500lb and 1000lb bombs, the 4000lb, 8000lb, and 12000lb "cookie" H.C bombs<ref>{{Cite web |last=U.S.N.B.D |date=1st November 1944 |title=BRITISH BOMBS AND FUZES PYROTECHNICS DETONATORS |url=https://stephentaylorhistorian.com/wp-content/uploads/2020/02/usnbd-british-bombs-and-pyrotechnics.pdf |access-date=31.05.2025}}</ref> and in the [[Bouncing bomb|Upkeep]], [[Tallboy (bomb)|Tallboy]] and [[Grand Slam bomb]]s as well as the drones employed in [[Operation Aphrodite]].<ref name="Barnes Wallis">{{cite web |title=Munitions Design |website=Barnes Wallis Foundation |url=https://www.barneswallisfoundation.co.uk/life-and-work/munitions-design/ |access-date=16 June 2022}}</ref><ref name="Webb">{{cite web |last=Webb |first=Mason B. |title=Operation Aphrodite |website=Warfare History Network |date=18 January 2019 |url=https://warfarehistorynetwork.com/2019/01/17/operation-aphrodite/ |access-date=16 June 2022}}</ref> Torpex has long been superseded by [[Composition H6|H6]] and [[Polymer-bonded explosive]] (PBX) compositions.<ref name="Graf">{{cite book |last=Graf |first=M.B.K. |title=Avro Lancaster |publisher=REI |year=2017 |isbn=978-2-37297-333-5 |url=https://books.google.com/books?id=EuFKDgAAQBAJ&pg=PA30 |page=30}}</ref><ref name="Persson">{{cite book |last1=Persson |first1=P.A. |last2=Holmberg |first2=R. |last3=Lee |first3=J. |title=Rock Blasting and Explosives Engineering |publisher=CRC Press |year=2018 |isbn=978-1-351-41822-5 |url=https://books.google.com/books?id=i2C1DwAAQBAJ&pg=PA73 |page=73}}</ref> It is regarded as [[obsolete]] and Torpex is unlikely to be encountered except in old munitions or [[unexploded ordnance]], although a notable exception to this is the [[Sting Ray (torpedo)|Sting Ray]] lightweight torpedo, which as of October 2020 remains in service with the Royal Navy and several foreign militaries. The German equivalent of Torpex was [[Trialen]].<ref name="Fedoroff">{{cite book |last1=Fedoroff |first1=B.T. |last2=Kaye |first2=S.M. |title=Encyclopedia of Explosives and Related Items |publisher=Picatinny Arsenal |issue=v. 10 |year=1960 |url=https://books.google.com/books?id=VdBTAAAAMAAJ&pg=RA2-PA55 |page=2-PA55}}</ref>

==Development==
Torpex was developed at the [[Waltham Abbey Royal Gunpowder Mills|Royal Gunpowder Factory, Waltham Abbey]], in the United Kingdom as a more powerful military alternative to TNT. [[RDX]] was developed in 1899. Though very stable and serving as the reference point by which the sensitivity of other explosives are judged, it was too expensive for most military applications and reserved for use in the most important products, such as torpedoes.{{sfn|Gannon|1996|p=183}} Aluminium powder was also added to the mix to further enhance the effect. Although both RDX and TNT have a negative [[oxygen balance]], the superheated aluminium component tends to contribute primarily by extending the expansion time of the explosive product gases.<ref name="Edri">{{cite journal |last1=Edri |first1=I. |last2=Feldgun |first2=V.R. |last3=Karinski |first3=Y.S. |last4=Yankelevsky |first4=D.Z. |title=Afterburning Aspects in an Internal TNT Explosion |journal=International Journal of Protective Structures |publisher=SAGE Publications |volume=4 |issue=1 |year=2013 |issn=2041-4196 |doi=10.1260/2041-4196.4.1.97 |pages=97–116| s2cid=109491342 }}</ref> [[Beeswax]] was also added as a [[phlegmatized|phlegmatizing]] agent, to reduce sensitivity to shock and impact.{{sfn|Gannon|1996|p=183}} Later, beeswax was replaced with [[paraffin wax]], and [[calcium chloride]] was added as a moisture absorber to reduce the production of [[hydrogen]] gas under high humidity.{{sfn|Gannon|1996|p=183}}

The production of RDX in the USA skyrocketed following the [[attack on Pearl Harbor]] by the Japanese. In April 1942, 100 tons of Composition C (88% RDX and oil desensitizer), also known as [[C-4 (explosive)|C4]], was ordered by the Office of Strategic Services.{{sfn|Baxter|2018| pages=25–32}} By 8 May 1945 ([[Victory in Europe Day]]) the Holston Ordnance Works had been in full production of RDX with no end in sight. In July of that year government officials informed the plant to not exceed production quotas (as had been the practice to that point) since they knew that the atomic bomb was near completion.{{sfn|Baxter|2018| pages=135-138}}

==See also==
* [[Amatol]]
* [[Hexanite]]
* [[List of explosives used during World War II]]
* [[Minol (explosive)]]
* [[Tritonal]]

== Sources ==
* {{cite book |last=Gannon |first=Robert |title=Hellions of the Deep: The Development of American Torpedoes in World War II |location=University Park, PA |publisher=Pennsylvania State University Press |date=1996 |isbn=0-271-01508-X| oclc=32349009}}
* {{cite book |last=Baxter |first=Colin F. |title=The Secret History of RDX |date=2018 |publisher=The University Press of Kentucky |doi=10.2307/j.ctt2111h03}}

== References ==
{{reflist}}

== Further reading ==
* {{cite report |last1=Rowland |first1=Buford |first2=William B. |last2=Boyd |title=U.S. Navy Bureau of Ordnance in World War II |location=Washington, D.C. |publisher=Government Printing Office |date=1947 |url=http://www.ibiblio.org/hyperwar/USN/Admin-Hist/BuOrd/BuOrd-6.html}}

[[Category:British inventions]]
[[Category:Explosives]]
[[Category:Trinitrotoluene]]