I don’t generally read history books, but at a recent meeting Stuart Arnold, instigator of the Systems Engineering Standard ISO 15288, and a leading light in the defence engineering community, showed me his copy of The Most Dangerous Enemy, A History of the Battle of Britain, by Stephen Bungay (Aurum, 2000). He said it was very interesting from a Systems Engineering point of view. (Since he showed me his, I showed him mine: I was reading Tom DeMarco and Tim Lister’s Waltzing with Bears.) So, I read it with interest.
The first casualty of war is truth, it’s said, and both sides had good reason to create myths for the Battle of Britain – whether of Aryan warrior-heroes with magic Messerschmitt Bf 109 swords, or of plucky little Britain, defenceless and unprepared, muddling through to fight off the ‘Hun’ through improvisation, daring, and happening to have ordered 1000 Hurricanes and 450 Spitfires, in peacetime, and trained their pilots, along with an Observer Corps of 30,000 men, and a continuous network of low- and high-level radar stations. Plainly the truth is very far from the myths, though as one pilot said, ‘never have so many owed so much to so few’ was true enough of the pilots’ mess bills.
There was, in fact, a carefully-engineered air defence system in place in Britain in 1940, a rock on which airborne attacks could break like water. The Luftwaffe didn’t know about it, and it’s just as well, or they might have prioritised better.
The high-level radar network consisted of a chain of about 15 tall thin steel pylons, sited from Norfolk to Devon, with a similar number of low-level radars. Each had a room nearby for the operators, who were trained to derive bearing, range, size of target, and (very roughly) altitude from the wiggly signals.
Radar detections and visual observations were telephoned back to sector command (one sector covered the Thames and east Kent, from Southend to Folkestone, for example). Sectors phoned group command: 11 Group, which through its location in the South-East had to do most of the fighting (under the inspired command of Keith Park), was at Uxbridge. Groups phoned Fighter HQ at Stanmore. Decisions were made at HQ and by Groups, and orders were given to the squadrons, which were stationed at many small airfields.
Now this, although entirely analogue, is a robust distributed system. The loss of any one radar or airfield, for instance, or any command post other than Fighter HQ (which was in a deep bunker), could be covered by its neighbours. The system could have been brought down by destroying all the radars and several control rooms, but this was hard to do. The radar towers were small and strong, and just swayed in the blast when bombed; the Luftwaffe didn’t even suspect that sector and group control rooms existed, and in any case these had backups – one was in a butcher’s shop. If you’re into -ilities, the system’s survivability and controllability were excellent. Its performance was also remarkably fast, through a simple hierarchy of point-to-point links: telephone lines. The Luftwaffe did manage to bring down parts of the system once or twice, mainly by accident: a bomb cut off much of Kent’s power grid, and several radars went down as a result; but not for long. The warning network worked splendidly; a wall of fighters met the Luftwaffe’s every move. That alone had a powerful demoralising effect.
The other, and far better known aspect of the system is its teeth: the fighter squadrons, and the aircraft themselves. On 1st July 1940 there were 48 squadrons of Spitfires and Hurricanes, each of about a dozen serviceable aircraft, with others under maintenance, and about 18 pilots. (There were also some Blenheims and Defiants.) Of those squadrons, by the way, 11 were up with 13 Group in Northumberland: squadrons were rotated to give weary pilots a rest, so there was always a reserve (whereas the Luftwaffe units fought continuously until exhausted).
The force was supported by many thousands of fitters and aircraftmen to keep the aircraft serviceable: between a quarter and a third of the planes with the squadrons were in maintenance at any one time. A steady stream of new pilots came out of flying training each month, though they had, horrifyingly, no training in fighting (and next to no gunnery practice, either); human operators are vital parts of most systems.
What is more, through the summer of 1940, the British aircraft industry was producing more than 400 fighters a month: twice what the Luftwaffe believed, and in fact easily enough to replace all the RAF’s losses – Fighter Command had more operational planes, and more pilots, in September than in July. The system had depth.
The design of the fighters themselves was far from a happy accident or the work of one or two heroes, like Hawker’s Sydney Camm who designed the Hurricane, Supermarine’s Reginald Mitchell who designed the Spitfire, and Henry Royce (of Rolls-Royce) who led the development of the Merlin engine which powered both planes. The Air Ministry itself had issued specifications to industry throughout the 1930’s, causing numerous prototypes to be developed.
Squadron Leader Ralph Sorley’s calculations and gunnery experiments led to the specification of the almost unbelievably heavy armament of 8 guns (Brownings) for each fighter, to ensure sufficient lethality with what he rightly believed would typically be an opportunity to fire of no more than two seconds. Extensive debate on many such issues within the Air Ministry led to the planning and construction of the entire air defence network.
The fighters, with monoplane wings containing the guns, retractable wheels, and less obvious things like reliable VHF radios, were state-of-the art. The Hurricane was built very simply with a metal frame, built out with wood and a canvas covering, making it strong and easy to manufacture (about 5000 man-hours per airframe).
The Spitfire
A perfect balance of -ilities?
The Spitfire had the famous elliptical wing, giving greater speed and manoeuvrability (perhaps the most critical -ility of all). This was at a price: 13000 man-hours per airframe. Willy Messerschmitt had optimised for speed and manufacturability (some call it producibility): only 4000 man-hours; but the Bf 109 was no faster than the Spitfire, and was consistently out-turned by it. Heinkel had considered the elliptical wing, but rejected it as too difficult to manufacture.
In the event, Germany only managed to produce about 200 fighters a month in the summer of 1940: not enough to keep up with their losses. Heinkel and Messerschmitt were right about the need to minimise manufacturing effort: if they had made more labour-intensive machines, such as four-engined heavy bombers (as many armchair warriors have suggested), they would have run out of planes and aircrew even sooner. We, on the other hand, can thank our lucky stars, and Mitchell, that no-one tried to do Value Engineering on the Spitfire’s wing.
There are plenty of other interesting design choices, but too many to mention here. It is often said that the cannon armament of the Bf 109 was superior to the Spitfire’s, but the cannon’s heavier calibre meant carrying only seven seconds’ worth of shells, as opposed to sixty seconds’ worth of bullets; and the vibration was severe and difficult to manage. Sorley’s guns seem to have achieved higher lethality than the Bf 109’s cannon in practice (number of planes shot down divided by number of bursts of gunfire). So that design trade-off was probably on the Spitfire’s side.
The Spitfire went on to be manufactured all through the war in many versions, getting heavier and faster in the process (as fast as the early jets). In this sense its design was robust – in the face of unknown extensions and developments. It is difficult to write requirements for this kind of robustness, sometimes called modifiability or extensibility. As a result, these requirements are usually watered down or dropped altogether, but as the Spitfire showed, modifiability can be a war-winning -ility, along with sheer performance.
Dependability also demands mention. The Spitfire’s build quality was far above the average for allied equipment at that time; as Bungay drily remarks, most allied equipment was much worse than the other side’s. One might contrast the allied Sherman tank with the fast, powerful, and well-armoured Panther, for instance. The Sherman’s grisly nickname was Ronson (a cigarette lighter): ‘one strike and it lights’. Lest anyone should think this anti-American, an all-British example is the Churchill tank. The driver could only exit when the gun was not pointing forwards, over his hatch: distinctly bad news when the tank was ‘brewing up’.
The Panther V: best of its class
The Spitfire was successful for many reasons, but one was that it always did what the pilot commanded with the stick, requiring only light finger pressure. In a tight turn or roll, the inner wing started to stall before the outer wing, causing a noticeable vibration, thus reliably warning the pilot. This in turn enabled every pilot to fly the plane to its limits – a life-saving feature. This wonderfully intuitive behaviour, ‘washout’, was created by a slight twist in the wing. Dependability, reliability, manoeuvrability, lethality, speed, controllability: no wonder the pilots were happy to have ‘beer, women, and Spitfires’.
The Luftwaffe never recovered from its losses in the Battle. In September, Goering went to the Pas-de-Calais to try to sort out the trouble, turning on all his undoubted charm.
Goering: What can I do for you?
Moelders: Upgraded engines for my Bf 109s.
Galland: A squadron of Spitfires.
It is said that Goering then lost his temper.
This wasn’t meant to be a book review. Bungay has however organized an astonishing wealth of accurate information to tell the story properly with hindsight, for no-one at the time really knew all of what was happening, though Keith Park seems to have suspected most of it.
A cover quote unflatteringly says ‘the most exhaustive and detailed account…’, thus totally failing to make the point that a large pile of pieces doth not a system make.
The book, however, for all its failings of style and repetitiveness, does brilliantly turn the evidence into a coherent story, blowing away a cloud of myths in the process. Oh, and who was ‘The Most Dangerous Enemy’? Britain, of course. Oberst Beppo Schmid, head of Luftwaffe intelligence in 1939, was right about that.
© Ian Alexander 2005