Thursday, April 7, 2011

Running Away to the Air: I: The Broad Atlantic

(Yes, I'm a wimp. But you can find the unbowdlerised version easily enough.)

The Battle of the Atlantic was one of the great campaigns of the Second World War. It's traditional at this point to say that it was decisive; I'd be inclined to be all blah blah about ships and ports and submarine tactics before I gave up the point. What I worry about is that it was fought by many participants and has a rich historiography. Far too much of which sucks in a way that goes to my own curiosities.
Again, the cynic in me reduces it to the worst in humanity. The Royal Air Force participated in the entire battle in all its facets, and another participant, the Admiralty, wishes that it hadn't. Oh, not that the Navy boys didn't want planes. Just that, you know, it wanted planes. This is the way of the bureaucracy; never happy unless it owns the assets its using. So if it has an intellectual hit-man used to subordinating his craft to the needs of the institution --a description that fits Stephen Roskill, official historian of the Royal Navy in World War II-- it can commission a version of history that turns the Admiralty's hopes and dreams of the 1950s into the history of the 1940s. Specifically, it can invent itself an Atlantic Air Gap. And a plane that can "patrol for three hours, 1100 miles from base," the Consolidated Liberator. A miracle of American technology that struck Britain out of the blue in 1941 and saved the day.

Okay, obviously the Atlantic is pretty broad. Even in the far northern latitudes between Newfoundland and Ireland, it is 1500 miles wide, and 800 miles from Cape Farewell at the southern end of Greenland to the Azores. And it is true that during WWII, the RAF only rated accepted one manufacturer's make of maritime patrol aircraft as a "Very Long Range" type. And it's true, too, that these were Consolidated LB-30 B-24 "Liberators," and that only about a dozen Liberator Is were available to 120 Squadron RAF in the fall of 1942, while other Liberators had been turned over to the RAF were being used for a variety of other purposes, including bombing, albeit only in the Middle East.  And so as sinkings grew apace on the broad Atlantic steeps, the Combined Chiefs of Staff became very upset, and in February told the air forces to pull it out and hand over more of these miracle planes for naval duties.
And so, by June of 1943, an RCAF squadron was flying ASW patrols in Liberators from Goose Bay in Newfoundland. (Because it took that long to work up Liberator Vs, which were different aircraft from Liberator Is, and so weighed more than Liberator Is, and thus had shorter ranges, until they were modified in various ways. Shall I speak more slowly and explain the difficult concept of how different planes are different, Mr. Terraine? Mr. Barnett, I assume that you know this, and are pretending not to. Commander Roskill, I know you do. It has been brought to your attention already.)
"But," you say, "hadn't Dönitz admitted defeat and pulled his boats out of the convoy battles by this point?" Yes, because surface patrols in the Bay of Biscay were catching and sinking far too many of his boats in transit, and the convoy battles were going against them, too. 9.2cm airborne radar was catching the Type VII boats transiting on the surface (since many of these were mounted on short range Liberators, the statistics can be quite neatly cooked), and they were far too short-legged to make the trip submerged. Meanwhile, the whole model of central control by radio was doubly vulnerable to decrypting and high-frequency direction finders on the escorts. I would argue that the spring weather was another important and neglected factor in the turnaround in the convoy battles, but that's by the by. If the whole story about magic VLR technology being hoarded by Bomber Command is wrong, what about the story of the magic plane to begin with?
Well, that's an interesting question to me, and hopefully to you too. So let's talk about it. First, let's put down the magic. All we need to know about a plane is how much fuel it carries, how much fuel lit burns per horsepower/hour at most efficient engine setting, and what cruising speed that power output corresponds too. That in turn comes back to drag, or rather "parasitic" and "induced" drag. The former can be reduced by designing your aircraft to the limits of state of the art. The latter is a function of the amount of wetted surface needed to keep the aircraft aloft. In short, less aerodynamic miracles, which have been mistakenly claimed for the B-24, and some aerodynamic optimising of less consequence that certainly do apply to the B-24, it comes down to weight,. Which brings us to the vicious cycle of range: more fuel means more range but in turn means more weight which means less range.
Now, it is a paradox of the Atlantic Gap that as big as it is, it was hardly unmastered by the air age. Amongst its victors were the standard RAF medium bomber of 1919; the RAF's basic trainer; and the RAF's standard wartime maritime long range patrol aircraft. Amongst the aircraft that were perfectly capable of patrolling the gap from bases in Greenland were pretty much all of its standard, shorter ranged patrol aircraft. They didn't, of course, because the real issue was climate, not distance. Winter flying is hard. Head winds cut into real air speed; icing adds weight while reducing lift; poor visibility makes patrolling difficult and navigation harder; long nights mean the same; the risk of fogged-in airfields means that aircraft have to have enough reserve fuel to fly to Gander instead of Goose Bay, or Akureyri instead of Keflavik. Icy runways reduce allowed takeoff weight. And in order to lug depth charges and radios and two different kinds of radar about in a reasonably comfortable plane, you need disposable lift. And the more weight you lift off the ground, the harder it is to achieve range. And the more range (fuel) you put into the aircraft, the more weight you have to lug around in the old Red Queen's Race. Wow. With all these difficulties, a forward-looking air force would be working on improving its long range performance from decade to decade, instead of letting the problem hit it in the face, like the RAF did, right?
Ahem. Exactly. Like that. Or that.
But enough of the good old days: what about the lead-up to war?
 On 7 November, the Air Ministry announced to a world that had been hearing a great deal about the ineffectuality of the RAF's air defence capabilities and the malign powers of bombers that its Long Range Distance Unit had completed a record flight between Ismaili, Egypt, and Darwin, Australia: 11,520 km. As the Air Ministry gravely assured the world that the fact that two of the three of the Flight's specially modified Vickers Wellesleys made the distance (while one landed 500 miles short) demonstrated that this was no mere stunt.
I wouldn't go that far, but I would point to the technical coverage. A long range record begins with fuel capacity, and thus disposable lift. To set their record, the LRU’s Wellesley’s had to carry an immense amount of fuel. At a rated empty weight of 11,000 lbs, they lifted off at 19,000 lbs. That's a better weight-lifting performance than that of the Boeing B-29 Superfortress that set the 1946 distance record! (Which is no big deal. Boeing and the USAAF hadn't had enough time to adapt the B-29 for long range record flying, and the engines wouldn't run cool at the very low power output ratings achieved by the much better-tested Pegasus XXIs.) And the basic design of the aircraft aimed at a high wing aspect ratio, accomplished using Vickers’ geodetic construction. We could spend all day on geodetics, another slightly-dubious utopian engineering miracle of a bygone age. The point is that it signalled an aged of mathematical analysis of loading stresses, of a new standard of aircraft design. To those who could read the signs, this was a signal that British aeronautical engineering had reached the level of analytical capability that would soon enough be manifested in fighters that were faster than they should be and bombers carrying impossible bomb loads. Good news in this parlous month, even if the Government wasn't sure how to handle it. (It would have been even better if the Maia had set the land record in its flight, setting up a one-two punch. It was not, however, to be.)
Besides quantity of fuel, the Wellesleys of the LRU also had very fuel efficient engines. The 9 cylinder, 28 litre radial Bristol Pegasus engine used in the Wellesley was a proven winner in the Italian license-built version, which powered Savoia-Marchetti SM 79s to the first five places in the 1937 Marseilles-Damascus-Marseilles long distance air race. But that was not thanks to the power plant. (At least not in general, because the Pegasus was an old and pedestrian engine; but the particular model of Pegasus used by the LRDU (the XXI) gave more than 1000 hp at takeoff, and a maximum of 825 hp at a cruising altitude of 4,000 feet. Compare those figures to the standards set by licensed versions of the Pegasus and you knew that something was up (higher grade alloys and nitriding, mostly), and that if your industry couldn't do the same to their versions of the Pegasus, your air force had no place in a sky where Merlins were flying.
The Italian winners also celebrated the contribution of their Claudel-Hobson "variable datum" carburettors, while the Pegasus XXI had a constant speed airscrew.  The previous generation of long range records had been very much products of the heroic age of aviation. The skilled pilots who set them had been able to control their engines almost by instinct, setting them for fuel-efficient flying by hand-adjusting the mixture control with an eye on the tachometer. This was impossible on the more complex Pegasus. Although Zero pilots were still doing it the old-fashioned way over Guadalcanal, “variable datum control" was automatic, servoe'd control. In other words, another example of the automatic control that I've already blah blah blah.
Finally, there was the fuel burnt by the LRDU: "100 octane" in lieu of the RAF's then-standard 87 octane. This was no technological miracle. The United States air forces had been procuring 100 octane for several years (although not, I'm told, 100 octane to Air Ministry standards). And it was easy enough to make 100 octane in the laboratory or even in the field with the right fuel stocks. What mattered here was the development of methods for making 100 octane on an industrial scale. The French and the Americans are still arguing about who was responsible for the key breakthrough here, but for any continental tinpot despot contemplating provoking a world war, the lesson was, or ought to have been that the new "reforming" processes only delivered about 80% as much avgas per unit feedstock as the old cracking methods. 

I've said about as much as I need to say here. If we were to boil down the sheer number of technological changes and breakthroughs required to make the LRDU possible, I'd have to talk about everything from slide rules to leathermaking. (No, seriously.) Not all of them, by a long shot came out of research promoted by the Air Ministry. But enough of them did for some of us (okay, me) to glimpse a vision of British society at mid-interwar, boarding its chariots of fire and driving towards a future in which all sorts of miracles might be possible. Or, alternatively, running away to the air. To boil this down to a single miracle plane from Los Angeles is to miss a relationship between military spending, industrial investment, and workforce training that might still have something useful to tell us.

And it's all a little funny considering that I'll be quoting Kirsten Seaver blasting people who think that North Atlantic weather makes too much difference, soon enough.

iHere are some books and articles I found useful in writing the unpublished article that I'm extracting and blogifying here:  H.F. King, “Transports Today and Tomorrow,” Flight, 28 April, 1938: c–f; R. A. E. Luard, “Transport Comparisons,” Flight, 6 January, 1938, 16; F. M. Green, “Aircraft Propulsion,” Proceedings of the Institute of Mechanical Engineers, 156 (January–December, 1947): 176–9, 182–5 Lutz Budraß, Flugzeugindustrie und Luftrüstung in Deutschland 1918–1945 (Düsseldorf: Droste, [1998]), 29–31, 78–80; Oliver Stewart, (“Egg Shell Airplanes: Geodetic Construction Increases Bomber Range 2 1/2 Times,”Aviation, July, 1936, 23–25; Brian Johnson and Terry Hefferman, Boscombe Down 1939–45: A Most Secret Place [{London}]: Jane’s, {1982},1–13]; W. O. Manning, and Sidney Camm comments on   J. Robinson, “Some Developments in Aircraft Production,” (J. Roy. Aero. Soc. 43 (1949): 39–66); T. P. Wright, “American Methods of Aircraft Production,” Jour. Roy. Aero. Soc 43 (1939): 51.); Irving Brinton. Holley, Jr., Buying Aircraft: Matériel for the Army Air Forces. A work in the series US Army in World War II (Washington: GPO, 1964), 541; Francis K. Mason, The Avro Lancaste (Bourne End, U.K.: Aston, 1989), 27–30; Eric J. Grove, ed. (Publications of the Naval Records Society Vol. 137): Defeat of the Enemy Attack on Shipping: A revised Edition of the Naval Staff History Volumes 1A (Text and Appendices) and Volume 1B (Plans and Tables) (Aldershot, U.K.; Ashgate, 1997)); Stephen W. Roskill, The War at Sea, 3 vols. History of the Second World War United Kingdom Military Series (London: HMSO, 1954-1961), where for discussions of the air component of ASW, see especially 2: 77-8, 81-2, 86-7, 89, 359-64, 450, and 3, 2: 389 and ff; Correlli Barnett, Engage the Enemy More Closely: The Royal Navy in the Second World War (London: Hodder and Stoughton, [1991); Clay Blair, Hitler’s U-Boat War. 2 vols (New York: Random House, 1996-8); John Buckley, “Air Power and the Battle of the Atlantic, 1939–45,” Journal of Contemporary History 28 (1993): 143–161; and The RAF And Trade Defence, 1919-1945: Constant Endeavour (Keele: Ryburn and Keele University Press, 1997); Elke C. Weal, Combat Aircraft of World War II (London: Botsford, 1977), 178; E. A. Harrop, “Planned Flying and Planned Servicing in the Royal Air Force and the Effects of Aircraft Design on Maintenance,” Jour. Roy. Aero. Soc. 51 (1949): 669; Richard J. Overy, The Air War, 1939-1945 (London: Europe, 1985; republished London: Macmillan, 1987), 39; John Terraine, Business on Great Waters: The U-Boat Wars, 1916-1945 (London: L. Cooper, 1989), 539-40; Max Hastings, Bomber Command (n.p.: M. Joseph, 1979; reprinted New York: Touchstone, 1987), 46, 178; The Mediterranean and the Middle East, History of the Second World War United Kingdom Military Series, Vol. 4, I. S. O. Playfair and C. J. C. Molotny (London: HMSO, 1966), 490–7; Wesley Frank Craven and James Lea Cates, eds., The Army Air Forces in World War Two, vol. 2, Europe: Torch to Pointblank; August 1942 to December 1943, by the United States Air Force Historical Center (Chicago: University of Chicago Press, [1949]), 15–18, 30–2, 220; J. David Brown, “The Battle of the Atlantic: Peaks and Troughs,” in To Die Gallantly: The Battle of the Atlantic, ed. Timothy J. Runyan and Jan M. Copes, 137-157 (Boulder: Westview Press, 1994); Alfred Price, Aircraft Versus Submarine: The Evolution of the Anti-Submarine Aircraft, 1912 to 1980 second ed. (London: Janes, 1980); Norman Friedman, Submarine Design and Development (Annapolis, Md.: Naval Institute Press, 1984); Willem Hackmann, Seek & Strike: Sonar, Anti-Submarine Warfare, and the Royal Navy, 1914-1954 (London: HMSO, 1984); World at Arms: A Global History of World War II (Cambridge: Cambridge University Press, 1994), 375; John Keegan, The Second World War (London: Hutchinson, 1989), 116, 120; Militärgeschichtliche Forschungsamt, Deutsche Reich und der zweiten Weltkrieg, 7 vols. to date (Stuttgart: Deutsche Verlag-Anstalt, 1979-), 6: 362; and Pierre Miquel, La Seconde Guerre Mondiale ([Paris]: Fayard, 1984), 481-3; Spenser Dunmore, The Official History of the Royal Canadian Air Force. Vol. 2. The Creation of a National Air Force ([Toronto]: University of Toronto Press in Cooperation with the Department of National Defence, 1986); Alex Niestlé, German U-Boat Losses During World War II: Details of Destruction [Annapolis, Md.: Naval Institute Press, {1998}], 1–142); “Civil Aviation News,” Flight, 21 November, 1946: 701–702; J. H. Famme, “Design Analysis of the Consolidated B-24 Liberator,” Aviation, July, 1945, 134; George R. Schairer, (the B-24's designer), “Range Versus Payload,” Aviation, August, 1938, 25-27, 71, 74, 77; Philip Joubert de la Ferté, “High Latitude Flying by Coastal Command in Support of Convoys to North Russia,” The Geographical Journal 108 (July–December, 1946),Eric Mensforth, “Airframe Production,” Jour. Roy. Aero. Soc. 51 (1946): 27).J. A. Ratcliffe, “Aerials for Radar Equipment.” J. Inst. Elec. Eng. 93, Part IIIA (Radiolocation) (1946): 22-32.Flight for Oct. 13, 1938, 311; Nov. 10, 1938, 414, Ibid., Nov 17, 1938, 458; Ibid., June 15, 1939, 616; December 16, 1937, 601; May 20, 1937, 502; and Aviation, December, 1938, 52 also G. H. Burchall, “North Atlantic Flights in 1938,” in H. G. Thursfield, ed. Brasssey’s Naval Annual, 1938 (London: W. Clowes, 1938), 209-19;“The Marseilles-Damascus-Paris,”Flight, August 26, 1937: 204-7;William Haynes, ed. American Chemical Industry, Vol. 6, The Chemical Companies (New York; London: Van Nostrand, 1949), 151-3, 216, 380-5; Maxwell Smith, Aviation Fuels (Cambridge, U.K.: G. T. Foulis, 1970), 20-2, 34-5, 50-6, 71, 73, 231-8; and N. O. Rawlinson, “Chapter 13: Aviation Fuels,” in Modern Petroleum Technology, 3rd. Ed., Hon. Ed. E. B. Evans (London: By the Institute of Petroleum, 1962), 495; on Allied fuel supply see Robert E. Wilson, “Petroleum and the War,” Transactions of the American Institute of Chemical Engineers 37 (1941), 508-09; and S. J. M. Auld, “Some American Thoughts on To-morrow’s Oil,” Institute of Petroleum Review, 1 (1947), 107; and W. M. Holaday, “Wartime Refinery Operations and Their Effect Upon Motor and Aviation Fuels,” SAE Journal, June, 1946, 303–9; for the development of 100/130 gasoline, see Henrietta M. Larson, et al., History of the Standard Oil Company (New Jersey): New Horizons, 1927-1950 (New York: Harper & Row, 1971), 503; F. Entwhistle, “Atlantic Flight and its Bearing on Meteorology.” Quarterly Journal of the Royal Meteorological Society (hereafter Quart. Jour. Roy. Met. Soc.) 64 (1938): 217.

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