Monday, January 13, 2014

Postblogging December, 1943, Technical Appendix, II

Edit: Bulwark seems to have been lost due to spontaneous detonation of ammunition, not propellant.

To this day I remember Chris Friedrichs (warning: UBC's security certificate for this site has expired) telling us that now that we were graduate students, we would appreciate being able to be in the library right up to Christmas, while undergraduates scattered off to home and hearth. 

Nowadays, the UBC libraries are closed during Saturnalia. 

Which is why the second technical appendix for December postblogging appears first. It has nothing to do with my losing precious research time exploring the 40 or so "Esquisse pour servire a l'histoire du Rome" inserted, apparently randomly and by an unknown hand, into the map pocket at the back of the library's 1876 Desjardins. In the spirit of the season....

That said, even without having covered the Fortune article yet, it is pretty clear that refrigeration needs a post, especially as I am going to link it to the Battle of North Cape. And by "needs a post," I mean, "needs multiple doctoral dissertations in economic, social, cultural and gender history." But that ain't gonna happen. So instead here is a discussion of the history of explosives, which is important because the transition to modern explosives required storage in temperature and humidity-controlled conditions that, in turn, led to state security-related investment in HVAC technology ahead of the rise of the cold chain logistics that has so clearly transformed our lives without being much investigated, although Jonathan Reese's book looks like an interesting first step.

So: the link to the Battle of North Cape? North Cape is the somewhat grandiose title for Bruce Fraser's successful mousetrapping of the battlecruiser KMS Scharnhorst on 26 December 1943. By keeping fast capital ships in Norwegian ports threatening the Russian convoys, the Germans were able to stretch Allied naval resources, with knock-on effects extending from the Eastern Front to the Pacific, until, as must inevitably happen, they ran out of capital ships.  Losing Scharnhorst --somehow-- was both inevitable and painful for the Germans, and an incremental step towards victory for the Allies. 

That's the top down view. Bottom up, it comes down to steam conditions, fire control solutions (1,2,3), volume of fire and progress in organic chemistry. (Noting that I got Robert Neville confused with James H. McGraw, Jr.)

The steam condition thing is interesting. Scharnhorst was very fast for its size due to operating with 850F steam, and, like its heavy cruiser contemporaries, suffered repeated machinery breakdowns because of it. So is it possible that the fatal blow that slowed it down at North Cape was inflicted internally, by steel failing in the wet blast? It's a wild-assed theory that I raise because of its salience to issues that do matter.  (Here's Antonio Bonomi promoting it.)

For fire control, we can notice that it was Bruce Fraser who  headed the team that designed the Admiralty Fire Control Table, and Bruce Fraser who won the Battle of North Cape. There's a lot going on here in the nascent history of computing, and I am not going to dissent from the common analysis that the radar stuff matters more than a weird little pneumatic computer, but there it is.

For volume of fire, I link to my posting on Jutland, the battle that the Royal Navy lost by letting institutional imperatives trump safety considerations, and the historical profession muffed by missing the well-publicised cause of the battlecruiser losses in favour of talking about "technological decline." Take what you will from that. The point is that Duke of York's ammunition chain was designed to make it mechanically impossible for a deflagration to propagate unchecked from the turret to the magazines. This was the right thing to do: even the most vigorous lip service to safety is still lip service. It is unfortunate that the resulting loss of fire opportunities keeps getting laid off on "unreliability," as though safety precautions were unmanly or something. Slow we are to learn.

So, ammunition storage is the previously-mentioned entre to the issue of the extremely rapid propagation of powered HVAC up and down the cold chain and of air conditioning on parallel lines. This takes us back to the introduction of the first 'modern,' artificial explosive, nitrocellulose, the explosive that was also a plastic!   I have talked about modern explosives, indirectly before. Specifically, I notice that I supplied the footnote, but not the discussion! As I move towards the climax of the munitions war, so it is time to get that stuff on the internet.

Explosives and Propellants: Volatile chemicals were used in WWII for a number of purposes, of which the most important were demolition explosives, weapon bursters and artillery propellants. As a class, explosives, bursters and propellants are self-reducing chemical compositions containing a high energy molecular bond and another capable of bonding with the molecules linked by that bond and so "reducing" it. When the bond is broken by an initial catalyzing event such as an electrical charge, percussion or ignition flame, the oxidant and reactant decompose into gasses, producing considerable energy.

 Contary to popular belief, this is not a particularly large amount of energy per unit mass compared with, say, gasoline. It is simply a matter of it being independent of external fuel, usually air. It does help if the resulting gas bubble is hot, and so expands rapidly. This is what we call the  “explosion,”  but I do not throw "deflagration" into these discussions just because I am incurably pedantic. Technically, a distinction is made on the basis of the shock wave propagation velocity between “deflagrants” and explosives. The distinction is that in open spaces the velocity of the shockwave is too low to carry actually burning gas, with the result that deflagrants burn, while explosives explode. Practically, the question is usually the "shattering" effect of the wave, or brisance. This is why black powder did not lead to civil engineers "blasting" their way through mountains, while dynamite did. Nitroglycerine has a high enough brisance; black powder does not. This is also why the Suez and Panama Canals were dug after nitroglycerine, and not before. And why plans were made to turn the Sahara into an inland sea in the late Nineteenth Century, and did not have to wait until (apparently)  the invention of LSD. 

Now if only we knew when and how the Cilician Gates and the Khyber Pass were cut....*

This does not mean that deflagrants are more (or less) stable in their response to external catalysis. Dynamite is particularly dangerous, because trinitrotoluene can “sweat” nitroglycerine. This is why it would be silly to say that the British propellants used at Jutland "caused" explosions that would not otherwise have happened, even if we did not already know what caused them.  As the tragic loss of Vanguard showed, British WWI-era propellants were unstable due to the presence of acidic iron pyrite particles struck up by factory yard railways. Spontaneous combustion can lead to deflagration in ammunition stores, and battleship magazines, being contained in armour and very full of deflagrant in proportion to surface area, can have overpressures build up that can break the ship's structure. But the propagation of deflagration from the turrets to the magazines depends on the presence of fuel on the route. 

Some explosives are suitable for demolition, others for loading into shells and bombs. The latter have to be quite insensitive, while the former have to be carried to the site, which puts a premium on efficiency by weight, especially for military purposes. Most of the explosives used by the British armed forces in WWII were still trinitrotoluene (TNT), and ammonium nitrate, but this need for weight economy had one of those unsuspected and wide ramifications so characteristic of the basic research and development projects of the 1930s, RDX. 

Production of ammonium nitrate and TNT continuous flow basis had been well established in WWI, and although there was substantial increase in productive capacity, development of industrial technique was left to Canadian and American engineers, who developed the batch production method until it was even more efficient than the 20 year old continuous flow method. RDX, still at a nascent stage of development, was more challenging. In 1920 the German, Herz (notice the formulation, beloved of the historical introduction to scientific papers? It means that the original author couldn't be arsed to look up "Herz's" first name. Very respectful. Unless we're decorously hiding the fact that he was Jewish.)

However, RDX had been previously identified by another German, Henning, in 1899. Unlike Henning, Herz recognised its explosive power, and published a patent that attracted attention in the United States and the United Kingdom, but only in the latter country was there concentrated work. A small-scale plant was producing 75lb/day at the Waltham Gunpowder Factory associated with the Royal Arsenal Woolwich by 1933. While not spelled out in this extract, where I am summarising some old textbook, this was to meet the needs of the Royal Engineers, who could not carry enough dynamite in divisional trains to knock down the new reinforced concrete bridges being thrown up in Europe to replace the ones blown up during the previous war. 

Meanwhile, work went on to improve the synthesis method, which gave a highly impure product. Production was still at the level of only a few hundreds of tons of RDX a year in the autumn of 1941, notwithstanding the opening of one unit at a dedicated factory at Bridgwater in August 1941. Even with the opening of the second unit in 1942, dependence on Canadian and American supply remained heavy, and as with progress in conventional explosives production, it was the North American manufacturers who developed high volume RDX production techniques. Fortunately, the impurities discovered in initial RDX production included other novel explosives of equal value, PETN and HMX. RDX was used in various mixtures by the British armed forces in WWII. Here it is not spelled out, as it is in Postan or in the report of the British Strategic Bombing Survey Unit, that the limited supply of RDX held up the introduction of aircraft bombs that made really big "booms."[1]

    Propellants also posed problems for chemists. Propellant gas is far too energetic to be contained by the metal of a gun barrel. The life of the metal at the breech, where the containment lasts longest, may be no more than 10 seconds, although this will correspond to a very large number of firings, from thousands in the case of a shoulder arm to at least more than 100 for a long naval rifle. Nor is the waste energy confined to the barrel. Incandescent gas is expelled from the gun barrel, producing an intense muzzle flash, which dazzles the weapon’s crew and identifies it to enemies during night fighting while contributing to muzzle wear through a back overpressure. The more energetically efficient the propellant, the greater the flash problems. Less energetic propellants, on the other hand, produced excessive amounts of smoke. All artillery propellants used in 1939–45 were organic compounds containing carbon and high energy nitrogen-oxygen bonds. The traditional gunpowder had long fallen out of favour, and the simplest propellants now used were nitrocellulose (cellulose nitrated with nitric acid) gelled with acetone, or double-base compounds containing a mixture of nitrocellulose and nitroglycerine with greater energy. The original modern brand name propellant was referred to as “Cordite,” and the name was perpetuated without distinction when pure nitrocellulose was succeeded in some navies by  double-base, triple-base and even multiple base compounds, with the result that the name itself becomes meaningless.  Double-base “cordites” are hotter and thus more energetically efficient. For example, Admiralty standard Cordite MC (65% nitrocellulose, 30% nitroglycerine, 5% cracked mineral jelly stabiliser) had a gas temperature of 3215K and a calorie content of 1025 calories/gram(?). The British services used an (inadequately) stabilised double base nitrocellulose-nitroglycerine as their standard propellant in WWI, and MC was virtually a better-stabilised descendant of that propellant, but by 1939 several triple-base propellants had become available. Cordite SC was 49.5% nitrocellulose, 41.5% nitroglycerine and 9% symmetrical diphenyl diethyl urea (Centralite), with a gas temperature of 970K and calorific value of 3090. The obvious major virtue of SC was that its lower gas temperature reduced barrel wear, but it was equally important that it could be extruded in high pressure presses, allowing its grains to be accurately sized and shaped cords and tubes. This mechanical modification gave significant consistency improvements. SC cords  in effect improved gun accuracy, while Cordite HSC or HSCK (potassium cryolite replacing Centralite) tubes gave higher muzzle velocity. Unfortunately, all of these propellants were doped with small amounts of chalk to counteract residual acidity, and the resultant calcium gave SC and HSC notoriously bright flashes. A flashless propellant was necessary, at least for special purposes.
During the interwar years intensive research at the Armament Research Department at Woolwich led to the development of a new propellant combining nitrocellulose and nitroglycerine with nitroguanidine (CH4N4O2, first prepared by Jousselin in 1877) and the gelatinising agent nitrodiethyleneglycol replacing acetone. The advantage of the nitroguanidine compositions was that they produced their impetus energy at much lower temperatures (as low as 2100"C compared with 2840"C for pure cordite), greatly reducing barrel erosion, while the new solvent permitted extrusion shaping as referred to above. The resultant so-called triple base propellant NF (55% nitroguanidine, 16.5% nitrocellulose, 21% nitroglycerine, 7.5% Centralite, 0.3% cryolite) was awkwardly bulky, and never available in adequate quantities because calcium carbide is required in the synthesis of nitroguanidine, and its production demanded excessive amounts of electrical power. The sole Commonwealth production facility in Niagara Falls never produced more than 19% of the originally projected output. NF was thus never as widely available as hoped, and this was exacerbated by a decision to supply the US Navy, which had not taken steps prewar to move beyond its traditional all-nitrocellulose cordite. Extrusion plant was also provided, but in inadequate quantities, preventing the U.S. Army from securing a supply of SC. 

Late war British tanks, using either HSK or some other material. (Notice how I weasel word around my suspicion that RDX was being added to the ammo of the 17 pounder and its successors, and that somehow no-one mentioned it? It's still a good theory, though.) This propellant had approximately an 11% advantage in potential muzzle energy compared with tanks still using conventional nitrocellulose at the expense of greatly increased barrel erosion. At this point, my original text put in more weasel words, to the effect that British performance may be more usefully compared with Japanese and German practice. Which is to say that the point here is not to invert the classic formulation according to which American arms were benefitted by American "high tech." It is not that Britain was "higher tech" than America. It was that Britain invested more in military explosives research. So, of course, did Germany and Japan and even Italy and Russia, which is why everybody's ammunition was better than American, at least to start with. Everyone used nitrocellulose and nitroglycerine mixes with Centralite and other minor additives and sometimes even RDX. There is the difference that the Japanese in particular did not use solventless-forming methods, but this goes to the shortage of high power hydraulic presses, not lack of chemical engineering know now. Instead, the well-known Japanese flashless powder substituted hydrocellulose and potassium sulphate for nitroguanidine and gained the same virtues of flashless affect and disadvantages of excessive charge bulk, albeit to a somewhat greater extent.[2]
Shell bursters demanded, like highly efficient demolition charges, the most energetic explosive possible, but a higher order of stability. WWI-era British shells were famously charged with Shellite (70% trinitrophenol, 30% dinitrophenol), by comparison with German shells, still charged with TNT desensitised by admixture with wax. Or perhaps I should say "infamous," as overly sensitive Shellite prematurely detonating was an issue in the Boer War. I believe that the report circulated by the High Seas Fleet immediately after Jutland, and still seen today, which describes British shells as prematurely detonating against light German structures, was either confirmation bias or, conceivably, black propaganda based on the Boer War controversy. 

It was, however, successful inasmuch as the alleged instability causing premature bursting led to a general reaction. Nelson and Rodney were given relatively light shells charged with block TNT. A few years later, this was seen to be overreaction, and there was a reversion to Shellite. Now, RDX can be mixed with the Shellite in significant proportions, but due to the limited supply of RDX, there was nothing like a 100% conversion. For example, naval use was confined to torpedoes, mines and guns likely to engage surfaced submarines.

The takeaway here, from a crowded post, is that the munitions ramp-up of World War II had huge implications for industry at large. At one level, there is a massive mechanical cold chain reaching out from San Francisco Bay into the Pacific, moving unprecedented amounts of nitrated chemicals (explosives!) towards Japan. Whether or not that compares in industrial skill-upsizing with the parallel and much more prosaic cold chain that got food to the fleet, I cannot say. 

It is interesting, and important, that the process of making explosives in world war-level quantities was transforming the chemical industry and getting it ready for the postwar plastics boom. But I cannot really link that to a Fortune article on refrigerators.

[1]Akhavan, 10–11, 36; William Hornby, Factories and Plant History of the Second World War; Civil Series (London: HMSO, 1958):112.
[2]P. R. Courtney-Green, Ammunition for the Land Battle (London: Brassey’s, 1991): 1–11; J. Akhavan, The Chemistry of Explosives (Cambridge, U.K.; Royal Society of Chemistry, [1998]): 9–11, 36, 171; E. Freeman, “Thermodynamic Properties of Military Gun Propellants,” 103–32 in Stiefel, ed. 122–27; J. M. Heimerl, “Muzzle Flash Kinetics and Modelling,” 261–310 in Stiefel, ed., 266; Constance M. Green,, H. Thomson, and P. Root, The United States Army in World War II: The Technical Services: The Ordnance Services: Planning Munitions for War (Washington, D.C.: GPO, 1953), 354; John Campbell, Naval Weapons of World War II (Annapolis: Naval Institute Press, 1994; Originally published London: Conway, 1985): 5, 172.

*It will be noticed that the Cilician Gates, as they look now, were cut by the Berlin-to-Baghdad engineers. However, here is an old antiquarian talking about the pre-railway cut, and, of course, supposing that it "must" have been made by Greeks. The interesting question is whether, if it were cut at the beginning of the Iron Age, it changed the traffic patterns out of central Anatolia and that this change can be deployed to explain the abandonment of Hittite identity. In a similar way, early movements from the Kabul River Valley to the Indian plain tend to go by high passes debouching at Taxila. It would be nice, given the importance of Taxila to world Buddhism, to have a sense of when the city's connections with the west were bypassed. I have no big theories about what might have resulted from that. So, in way of compensation, I was going to link to the so-crazy-that-it-actually-turns-the-corner-to-plausibility theory that Ashoka was actually Demetrius I of Bactria, but it's been purged from Wikipedia. This is as it should be, but also a shame.


  1. As the tragic loss of Vanguard showed, British WWI-era propellants were unstable due to the presence of acidic iron pyrite particles struck up by factory yard railways.

    This could really do with a link? That sounds interesting.

    Off topic, take a look under the green forest cover of New England, with LASERS! And find evidence for not just one, but several, major reshapings of the landscape - that seem to have left property lines untouched since the early 1700s, as the woods were cleared and put under the plough and then when the cities grew and the woods came back.

  2. John Campbell's Naval Weapons of World War II isn't on the Internet. Something about the publisher being able to sell it at $347 a pop....

    ""British propellant had a poor reputation after he 1914--1918 War . . . . Much work was done on these problems in the 1920s, and the spontaneous explosions were traced beyond any reasonable doubt to the presence in the nitrocellulose of dust impurities 0.005in or less in diameter with a high content of iron pyrites (iron disulphide). The sulphur in the pyrites slowly oxidised to sulphuric acid, which corroded the nitrocellulose with local evolution of heat sufficient to cause spontaneous ignition. The source of the contamination was easy to find in pyritic coal dust, untarred cinder paths and dumps of pyrites, and the cure was obvious...." (5)

    Campbell does not go on to say what the obvious cure was, but I'm going to go with adding chalk as a buffering agent.