Cordite is a family ofsmokeless propellants developed and produced in Britain since 1889 to replaceblack powder as a militaryfirearm propellant. Cordite is a mixture of nitrocellulose and nitroglycerine, and is therefore a mixture of a chemical high explosive stabilized with a low explosive. These produce a subsonicdeflagration wave rather than the supersonicdetonation wave produced by brisants, orhigh explosives.[not verified in body] The hot gases produced by burning gunpowder or cordite generate sufficient pressure to propel abullet orshell to its target, but not so quickly as to routinely destroy thebarrel of the gun.[not verified in body]
Cordite was used initially in the.303 British, Mark I and II, standardrifle cartridge between 1891 and 1915.[not verified in body] Shortages of cordite inWorld War I led to the creation of the "Devil's Porridge" munitions factory (HM Factory, Gretna) on the English–Scottish border, which produced around 800 tonnes of cordite per week. The UK also imported some United States–developed smokeless powders for use in rifle cartridges. Cordite was also used for large weapons, such astank guns,artillery, and naval guns. It has been used mainly for this purpose since the late 19th century by the UK andBritish Commonwealth countries. Its use was further developed beforeWorld War II, and as 2-and-3-inch-diameter (51 and 76 mm)Unrotated Projectiles for launchinganti-aircraft weapons.[1] Small cordite rocket charges were also developed forejector seats made by theMartin-Baker Company. Cordite was also used in the detonation system of theLittle Boy atomic bombdropped over Hiroshima in August 1945.[2]
The term "cordite" generally disappeared from official publications between the wars. During World War II,double-base propellants were very widely used, and there was some use of triple-base propellants by artillery. Triple-base propellants were used in post-war ammunition designs and remain in production for UK weapons; most double-base propellants left service as World War II stocks were expended after the war. For small arms it has been replaced by other propellants, such as theImproved Military Rifle (IMR) line of extruded powder or the WC844ball propellant currently in use in the5.56×45mm NATO.[3] Production ceased in the United Kingdom around the end of the 20th century, with the closure of the last of the World War II cordite factories,ROF Bishopton. Triple-base propellant for UK service (for example, the105 mm L118 Light Gun) is now manufactured in Germany.
Gunpowder, a combustable mixture ofsulfur,charcoal andpotassium nitrate (also known assaltpetre), was the original propellant employed infirearms andfireworks. It was used from about the 10th or 11th century onward, but it had disadvantages, including the large amount of smoke it produced. With the 19th-century development of various "nitro explosives", based on the reaction ofnitric acid mixtures on materials such ascellulose andglycerin, a search began for a replacement for gunpowder.[4]
The first smokeless powder was developed in 1865 byJohann Edward Schultze. At the time of this breakthrough, Schultze was a captain of Prussian artillery. Schultze eventually rose to the rank of colonel. His formulation (dubbedSchultze Powder) was composed ofnitrolignose derived from nitrated wood grains, impregnated withsaltpetre orbarium nitrate.[5][6][7]
In 1882, theExplosive Company of Stowmarket introducedEC Powder, which contained nitro-cotton and nitrates of potassium and barium in a grain gelatinised by ether alcohol. It had coarser grains than other nitrocellulose powders. It proved unsuitable for rifles, but it remained in long use for shotguns[8] and was later used for grenades and fragmentation bombs.[9]
In 1884, the French chemistPaul Vieille produced a smokeless propellant that had some success. It was made out ofcollodion (nitrocellulose dissolved inethanol andether), resulting in a plastic colloidal substance which was rolled into very thin sheets, then dried and cut up into small flakes. It was immediately adopted by the French military for their Mle 1886 infantry rifle and calledPoudre B (forpoudre blanche, orwhite powder) to distinguish it fromblack powder (gunpowder). The rifle and the cartridge developed to use this powder were known generically as the8mm Lebel, after the officer who developed its 8 mmfull metal jacket bullet.[10]
The following year, 1887,Alfred Nobel invented andpatented a smokeless propellant he calledBallistite.[11] It was composed of 10%camphor, 45%nitroglycerine and 45% collodion (nitrocellulose). Over time the camphor tended to evaporate, leaving an unstable explosive.[12]
A United Kingdom government committee, known as the "Explosives Committee", chaired by SirFrederick Abel, monitored foreign developments in explosives and obtained samples of Poudre B and Ballistite; neither of these smokeless powders was recommended for adoption by the Explosives Committee.[citation needed]
Abel, SirJames Dewar and W Kellner, who was also on the committee, developed and jointly patented (Nos 5,614 and 11,664 in the names of Abel and Dewar) in 1889 a new ballistite-like propellant in 1889. It consists of (by weight) 58%nitroglycerin, 37%guncotton (nitrocellulose) and 5%petroleum jelly. Usingacetone as asolvent, it was extruded asspaghetti-like rods initially called "cord powder" or "the Committee's modification of Ballistite", but this was swiftly abbreviated to "Cordite".[citation needed]
Cordite began as adouble-base propellant. In the 1930s,triple-base was developed by including a substantial proportion ofnitroguanidine. Triple-base propellant reduced the disadvantages of double-base propellant – its relatively high temperature and significant flash.Imperial Chemical Industries's (ICI) World War II double-baseAN formulation also had a much lower temperature, but it lacked the flash reduction properties of N and NQ triple-base propellants.[citation needed]
Whilst cordite is classified as anexplosive, it is not employed as a high explosive. It is designed todeflagrate, or burn, to produce high pressure gases.[citation needed]
Alfred Nobel sued Abel and Dewar over an allegedpatent infringement. His patent specified that the nitrocellulose should be "of the well-known soluble kind". After losing the case, it went to theCourt of Appeal. This dispute eventually reached theHouse of Lords, in 1895, but it was finally lost because the words "of the well-known soluble kind" in his patent were taken to mean the soluble collodion, and hence specifically excluded the insoluble guncotton.[13] The ambiguous phrase was "soluble nitro-cellulose": soluble nitro-cellulose was known asCollodion and was soluble inalcohol. It was employed mainly for medical andphotographic use. In contrast, insoluble in alcohol, nitrocellulose was known asgun cotton and was used as an explosive.[13][14] Nobel's patent refers to the production ofCelluloid usingcamphor and soluble nitrocellulose; and this was taken to imply that Nobel was specifically distinguishing between the use of soluble and insoluble nitrocellulose.[14] For a forensic analysis of the case, see The History of Explosives Vol II; The Case for Cordite, John Williams (2014). However, in her comprehensive 2019 biography of Alfred Nobel[15]Ingrid Carlberg notes how closely Abel and Dewar were allowed to follow Nobel's work in Paris, and how disappointed Nobel was with how this trust was betrayed. The book argues for Nobel as the original inventor and that the case was lost because of an unimportant technicality.
It was quickly discovered that the rate of burning could be varied by altering the surface area of the cordite. Narrow rods were used in small-arms and were relatively fast burning, while thicker rods would burn more slowly and were used for longer barrels, such as those used in artillery and naval guns.[citation needed]
The original Abel-Dewar formulation was soon superseded, as it caused excessivegun barrel erosion. It has since become known asCordite Mk I.[citation needed]
The composition of cordite was changed to 65% guncotton, 30% nitroglycerin (keeping 5% petroleum jelly), and 0.8% acetone shortly after the end of theSecond Boer War. This was known asCordite MD (modified).[16]
Cordite MD cartridges typically weighed approximately 15% more than the cordite Mk I cartridges they replaced, to achieve the same muzzle velocity, due to the inherently less powerful nature of Cordite MD.[17]
During World War I, acetone was in short supply in Great Britain, and a new experimental form was developed for use by theRoyal Navy.[18] This wasCordite RDB (=ResearchDepartment formulaB); which was 52%collodion, 42%nitroglycerin and 6%petroleum jelly. It was produced atHM Factory, Gretna;[18] and theRoyal Navy Cordite Factory, Holton Heath.[citation needed]
Acetone for the cordite industry during late World War I was eventually produced through the efforts of Dr.Chaim Weizmann, considered to be the father ofindustrial fermentation. While a lecturer atManchester University Weizmann discovered how to use bacterial fermentation to produce large quantities of many desired substances. He used the bacteriumClostridium acetobutylicum (the so-called Weizmann organism) to produce acetone. Weizmann transferred the rights to the manufacture of acetone to the Commercial Solvents Corporation in exchange for royalties. After theShell Crisis of 1915 during World War I, he was director of the British Admiralty Laboratories from 1916 until 1919.[citation needed]
Cordite RDB was later found to become unstable if stored too long.[citation needed]
Research on solvent-free Cordite RDB technologically extremely similar to ballistite continued primarily on the addition of stabilizers, which was based on German RP C/12 propellant featuring significant amounts ofcentralite (Called "carbamite" in British parlance) and led to the type commonly used inWorld War II as the main naval propellant. In Great Britain this was known asCordite SC (= Solventless Cordite), and it required production facilities separate from classical cordite.
Cordite SC was produced in different shapes and sizes, so the particulargeometry of Cordite SC was indicated by the use of letters or numbers, or both, after the SC. For example, SC followed by a number was rod-shaped cord, with the number representing the diameter inthousandths of an inch. "SC T" followed by two sets of numbers indicated tubular propellant, with the numbers representing the two diameters in thousandths.[citation needed]
Two-inch (approximately 50 mm) and three-inch (approximately 75 mm) diameter, rocket Cordite SC charges were developed in great secrecy before World War II for anti-aircraft purposes—the so-calledZ batteries, using 'Unrotated Projectiles'.[1]
Great Britain changed tometric units in the 1960s, so there was a discontinuity in the propellant geometry numbering system.[citation needed]
An important development during World War II was the addition of another explosive,nitroguanidine, to the mixture to formtriple-base propellant orCordite N andNQ. The formulations were slightly different for artillery and naval use. This solved two problems associated with the large naval guns fitted to British Navy'scapital ships: gun flash and muzzle erosion. Nitroguanidine produces large amounts ofnitrogen when heated, which had the benefit of reducing the muzzle flash, and its lower burning temperature greatly reduced the erosion of the gun barrel.[citation needed]
N and NQ were also issued in limited amounts to ammunitions used by the British25-pdr and5.5-inch land-based artillery pieces.[citation needed]
After World War II production of double-base propellants generally ended. Triple-base propellants, N and NQ, were the only ones used in new ammunition designs, such as the cartridges for 105 mm Field and for 155 mmFH70.[citation needed]
In Great Britain, cordite was developed for military use at theRoyal Arsenal by Abel, Dewar and Kellner,Woolwich,[19] and produced at theWaltham Abbey Royal Gunpowder Mills from 1889 onwards.[20]
At the start of World War I, cordite was in production atWaltham Abbey Royal Gunpowder Mills and by seven other suppliers (British Explosives Syndicate Ltd, Chilworth Gunpowder Company Ltd, Cotton Powder Company Ltd, Messrs Curtis's and Harvey Ltd, National Explosives Company Ltd, New Explosives Company Ltd and Nobels Explosive Company Ltd).[21] Existing factories were expanded and new ones built, notably by Nobel's at Ardeer,HM Factory, Gretna, which straddled theScotland-England border atGretna, and theRoyal Navy Cordite Factory, Holton Heath. A factory was also established by the Indian Government at Nilgris. Both the Gretna and the Holton Heath cordite factories closed at the end of World War I.[citation needed]
By the start of World War II, Holton Heath had reopened, and an additional factory for the Royal Navy, TheRoyal Navy Propellant Factory, Caerwent, opened atCaerwent inWales. A very largeRoyal Ordnance Factory, ROF Bishopton, was opened in Scotland to manufacture cordite for the British Army and the Royal Air Force. A new cordite factory at Waltham Abbey and two additional ROF's—ROF Ranskill andROF Wrexham—were also opened. Cordite produced in these factories was sent tofilling factories for filling into ammunition.[citation needed]
The British Government set up additional cordite factories, not under Royal Ordnance Factory control but as Agency Factories run on behalf of theMinistry of Supply (MoS). The company ofICI Nobel, at Ardeer, was asked in 1939 to construct and operate six factories in southern Scotland. Four of these six were involved in cordite or firearm-propellant manufacture. The works at MoS Drungans (Dumfries) produced guncotton that was converted to cordite at MoS Dalbeattie (triple-base cordite) and at MoS Powfoot (monobase granulated guncotton for small-arms). A smaller site at Girvan, South Ayrshire, now occupied by Grant's distillery, produced cordite andTNT.[22] The ICI Ardeer site also had a mothballed World War I Government-owned cordite factory.[23]
35% of British cordite produced between 1942 and 1945 came from Ardeer and these agency factories.[24] ICI ran a similar works at Deer Park (which was also confusingly known as Ardeer after the adjacent suburb) near Melbourne in Australia and in South Africa.[24]
Additional sources of propellant were also sought from the British Commonwealth in both World War I and World War II.Canada, South Africa, and Australia had ICI-owned factories that, in particular, supplied large quantities of cordite.[citation needed]
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Canadian Explosives Limited was formed in 1910 to producerifle cordite, at itsBeloeil factory, for theQuebecArsenal. By November 1915 production had been expanded to produce 350,000 lb (159,000 kg) of cordite per month for theImperial Munitions Board.[25]
The Imperial Munitions Board set up a number of additional explosives factories inCanada. It builtThe British Cordite Ltd factory atNobel, Ontario, in 1916/1917, to produce cordite. Production started in mid-1917.[25]
Canadian Explosives Limited built an additional cordite factory at Nobel, Ontario. Work started in February 1918 and was finished on 24 August 1918. It was designed to produce 1,500,000 lb (681,000 kg) of cordite per month.[25]
Factories, specifically "heavy industry" (Long, and Marland 2009) were important for the provision of munitions. Cordite factories typically employed women (Cook 2006) who put their lives at risk as they packed the shells.[citation needed]
Large quantities of cordite were manufactured in both World Wars for use by the military.[26]
Prior toWorld War I, most of the cordite used by the British Government was produced in its own factories. Immediately prior to World War I, between 6,000 and 8,000 tons per year of cordite were produced in the United Kingdom by private manufacturers; between 1,000 and 1,500 tons per year were made byNobel's Explosives, at Ardeer.[23] However, private industry had the capability to produce about 10,000 tons per year, with Ardeer able to produce some 3,000 tons of this total.[23]
At the start of World War I, private industry in the UK was asked to produce 16,000 tons of cordite, and all the companies started to expand.[23]HM Factory, Gretna, the largest propellant factory in the United Kingdom, which opened in 1916, was by 1917 producing 800tons (812tonne) of Cordite RDB per week (approximately 41,600 tons per year).[18][23] TheRoyal Navy had its own factory atHolton Heath.[27]
In 1910,Canadian Explosives Limited produced 3,000 lb (1,362 kg) ofrifle cordite per month at itsBeloeil factory, for theQuebecArsenal. By November 1915 production had been expanded to 350,000 lb (159,000 kg) of cordite per month (approximately 1,900 tonnes per year).[25] The Canadian Explosives Limited cordite factory atNobel, Ontario, was designed to produce 1,500,000 lb (681 tonne) of cordite per month (approximately 8,170 tonnes per year).[citation needed]
HM Factory, Gretna, and theRoyal Navy Cordite Factory, Holton Heath, both closed after the end of the war and the Gretna factory was dismantled.[18] This left the Waltham Abbey and Ardeer factories in production.[citation needed]
As noted above, in addition to its own facilities, the British Government had ICI Nobel set up a number of Agency Factories producing cordite in Scotland, Australia, Canada and South Africa.[citation needed]
