The Eternal Debate

imgres Since the end of the Battle of Britain, there has been     almost endless discussion about the various merits of the fighters involved. Most conclude, however, that, on balance, there was not much in it between the Spitfire Mk I and the Me 109E series. On paper, the maximum speeds of the two were about the same, while the Spitfire could out-imgres-1turn an Me 109E, something that has always been viewed as a key attribute in dog-fighting. ‘But who gives a bugger about turning?’ says Tom Neil, a former pilot in 249 Squadron and veteran of the Battle. ‘You don’t need to turn. All you need to do is go like a bat out of hell, catch the other fellow, fire your guns, and disappear. These things the Me 109 did very, very well. It could catch us and it could run away from us, almost at will.’

spitfire_Richard Paver Photography BG Tom is quite right. When compared with the either the Spitfire or Hurricane Mk Is, the Me 109E had a superior rate of climb and speed of dive, and most definitely vastly superior firepower. These were the key ingredients to successfully shooting down lots of the enemy in the summer of 1940.

The reason for its superb acceleration was a combination of its supercharger, fuel-injection and electric variable pitch propeller, all of which also contributed to its swift rate of climb.  During the first half of the summer of 1940, Me109Es had a far more sophisticated propeller than either Spitfires or Hurricanes, something that was revealed by extensive tests at Farnborough in May and June 1940 on two intact Me109s captured intact in France.  Up to this time, British fighters, on the other hand, had two-speed propellers, that is, the angle of their propellers could be varied between just two settings, coarse and fine. Coarse pitch meant its blades were angled so that as it rotated, it would ‘bite’ the air more effectively. At fine pitch, the propeller was at a flatter angle, which allowed the engine revs to be greater, but did not provide as much ‘bite.’ But getting the best from a plane meant striking a balance between performance and fuel consumption in a range of different flying altitudes, speeds and other scenarios such as, for example, diving or climbing. Thus having just two pitch options was somewhat limiting, especially when compared to a variable pitch propeller, which enabled a pilot to maintain a far more varied and subtle use of the interchange between thrust, engine revs and power.

On the back of the Farnborough tests, however, first Spitfires and then Hurricanes were hurriedly converted to De Havilland variable pitch propellers. In an astonishing feat of British production, over a thousand existing, repaired and new-build Spitfires and Hurricanes had been converted by 15 August, which did much to improve their performance during the crucial weeks of the Battle.

This put them on an equal footing with the 109E in only one regard, however.  The Me 109’s ability to dive away from any mêlée quickly was largely due to the DB601’s fuel injection, which Spitfires and Hurricanes did not have, nor would not acquire throughout the Battle. Rather, the Merlin engine which powered the British fighters relied on a carburettor. Any sudden dive downwards created negative gravity, or negative-g, which not only pushed the pilot up against his straps, but also forced all the fuel to the top of the float chamber. If the negative-g was maintained, this would cause the carburettor to become flooded with fuel because the float was no longer controlling the fuel flow into the carburettor. This in turn then caused the engine to cut out (called a rich-cut), producing a large puff of black smoke as it did so. This only lasted as long as the duration of the negative-g, and might only take a few seconds, but it was in that moment that an enemy could make good his escape.

This was not an issue for the Me 109 because with its pioneering Bosch fuel injection fuel was pumped into the engine consistently even when under negative-g. It was this feature of the Me 109 that saved Siegfried Bethke’s life on 2 September. A pilot in 2/JG 2, Siegfried had been around 12,000 feet above the eastern edge of London, and escorting bombers, when they were, as expected, attacked by British fighters. In a confused tussle, Siegfried was performing a very steep left turn, and glancing up in his mirror his blood suddenly chilled. Just behind him was a Hurricane with all of its eight machine guns spitting bolts of lightning at him. He knew that the 109 could out-dive the British fighters and that therefore his only chance of escape was by quickly diving away. The Hurricane followed after him, but could not catch up, having lost precious seconds.

The Me 109 also suffered little sideslip when banking, unlike the Spitfire and Hurricane. Sideslip occurred because of the change of airflow caused by the turn, which meant it would literally slide, or drop a bit of altitude. But by keeping this to a minimum, an attacker could keep an enemy aircraft in his sights with greater ease.

It is true that in the Daimler-Benz 601 the Me 109 had a beast of a powerplant, but in addition to its supercharger and airscrew, it was the thrust from this engine combined with superb airframe design and high wing loading that gave the Me 109E such high speed and aggressive handling. Wing loading refers to the weight of the aircraft divided by the area of the wing, and on the Me109E was 32 lb per square foot, while that of the Spitfire Mk I was 25 lb per square foot – in other words, it was much higher on the Me109 than on the Spitfire. This was because the Me 109E had comparatively small wings; the Spitfire had very thin wings, but their elliptical shape gave them quite a large surface area. The advantage of small wings is that speed is created by forward thrust countering drag; thus, the smaller the wings, the less the drag, and this contributed to greater speed.

There is, however, a pay-off for having high wing loading, namely that the aircraft will stall at higher speeds. A stall occurs when the airflow over the wing reaches a stage where it no longer provides lift, at which point the aircraft starts to drop out of the sky. This is not necessarily a problem when operating at height, but it can be when taking off and landing, when the aircraft would be necessarily travelling at low speeds. Inexperienced Me 109 pilots could find taking off particularly difficult because the propeller would be rotating one way, creating enormous torque. This meant that lift was being caused over one of the wings and prop-wash – airflow over the wing caused by the propeller – over the other. This needed to be corrected by use of the rudder and aileron, but if a pilot was not careful, he could over-correct, the aircraft would roll, and he would crash into the ground.

When coming in to land, the high stalling speed was lowered by slats at the front of the wing, which automatically extended from the leading edge of the wings at around 110 mph, and flaps at the back, thus giving the wings greater surface area and preventing the aircraft from stalling. Me109 pilots, however, could use this capability in combat to help them achieve a tighter turn. The theoretically minimum turning circle of the Me 109E was 885 feet, while that of a Spitfire was 696 feet. Any aircraft will lose speed when turning, which is one of the reasons not to turn in the first place when in the middle of a dogfight. However, by pulling back on the stick, and allowing the slats to open an Me 109 could, in fact, out-turn a Spitfire.

In any case, as was revealed by the Farnborough tests, Spitfire and Hurricane pilots were often reluctant to push their aircraft in as tight a turn as possible because they were worried about stalling. A pilot could feel the aircraft nearing the stall as the control column would start to shake; it was what was called ‘pre-stall buffeting’. It was easy to recover an Me 109E from a stall, but this was not always the case with the Hurricane, which, despite being a very forgiving aircraft, could flip over and go into a spin. ‘The Hurricane would always drop a wing,’ says Pete Brothers, a pilot with 32 and 257 Squadrons. ‘It was notorious for it.’ The Spitfire, despite its thoroughbred, silky handling, could also prove a handful if ever pushed to stalling point. Pilots were warned of this in the accompanying Pilot’s Notes. ‘Never attempt a “tail-chase” with an enemy aeroplane having a smaller turning circle than the Spitfire,’ it noted. ‘If stalling incidence is reached, the aeroplane usually does a violent shudder, with a loud “clattering” noise, and comes out of the turn with a violent flick. This would be a serious loss of advantage in a combat.’

Certainly, during the Farnborough tests, the pilots, despite being highly experienced combat and test pilots, were nervous about stalling both the Spitfire and the Hurricane. ‘In a surprisingly large number of cases, however,’ noted the report, ‘the Me 109 succeeded in keeping on the tail of the Spitfire or Hurricane during these turning tests, merely because our pilots would not tighten up the turn sufficiently from fear of stalling and spinning.’ It is interesting that those writing the report felt it necessary to underline this key part of their findings. In other words, what was comparable on paper did not really represent what was happening in the air. The Me 109E, on the other hand, was less likely to flip and spin in a stall, and its high stalling speed could be used by skilled pilots to good effect in combat, because a stall enabled it to lose sudden height very quickly, a useful trick when being pursued.

It was also true that the Me 109E had a comparatively narrow undercarriage, which made it less stable on the ground, potentially a hazard in the hands of inexperienced pilots when touching down. However, although its roots were much narrower than that of the Spitfire, its legs were splayed so that in fact, they were about the same width as that of the British fighter. The Hurricane, with its inward folding undercarriage, was the most stable of the three on the ground, but the great advantage of the Me 109 arrangement was that the legs were attached to the underside of the fuselage rather than the wing. This meant wings could be replaced with comparative ease without having to dismantle the wheels, legs and hydraulics. It is a myth, however, that it was the narrow undercarriage that made the Me109 so potentially lethal to the inexperienced. Rather, it was its unforgiving nature at low speeds, more a result of its high wing loading and the enormous torque of its DB601 engine. At Guines, for example, where JG54 were based during the Battle, there was a track running about two-thirds of the way across it. ‘It was only a slight dip,’ says Hans-Ekkehard Bob, a pilot in III/JG54, ‘but it was just where you took off and where you landed back down again. If you didn’t judge it right, it was very easy to jolt the plane as the wheels went over it. Then a wingtip would hit the ground, then the propeller, and before you knew it the machine had flipped. It never happened to me, but it did to lots of others.’

It is undoubtedly the case that considerable numbers of Me 109s were lost or damaged in flying accidents, but there is little to suggest they were any higher than those of the RAF, which suffered its fair share too. Despite its wide and stable undercarriage, a staggering 463 Hurricanes, for example, were damaged as a result of accidents between 10 July and 31 October. Some of these were minor prangs, others were fatal. ‘Landed with undercarriage retracted’, or ‘overshot’, or ‘hit rough ground’ were common lines scrawled across the accident report cards. So too was ‘failed to open quick enough – aircraft stalled’. ‘Taxied wrong way after landing on a very dark night,’ read another report, ‘ran into ditch.’ ‘Carelessness. Unnecessary taxying in the dark when out of touch with Aldis lamp.’ There were also other non-combat-related losses: mechanical failure, mid-air collisions, navigation error, lack of fuel. In fact, it has been suggested that these contributed as much as 20–30 per cent of losses during the Battle – on both sides. Most were caused by a mixture of inexperience, lack of concentration and fatigue.

Yet, interestingly, the Farnborough tests also revealed that the British pilots had no difficulties landing or taking off in the Me 109E once they got used to it. Nor did Hans-Ekkehard Bob or Siegfried Bethke. Ulrich Steinhilper, a pilot with 3/JG52, dropped a wingtip and damaged his 109 when he took off and suddenly hit a strong cross-wind. He had also just had a few whiskies since he had not been expecting to fly. Clearly, he had not been concentrating as hard as usual.

What this showed was in the hands of very good and experienced pilots the Me 109 held no terrors. It was the inexperienced who struggled with it. In contrast, most pilots found the Spitfire and Hurricane both very straightforward and forgiving to fly. A really superb pilot flying a Spitfire could not get much more out of it than an average pilot. An excellent pilot flying an Me109, however, could do all sorts of things in his machine that a pilot of lesser ability would never achieve. Already, the leading German aces – or Experten, as they were called – were amassing considerable scores during the summer of 1940, Dolfo Galland and Werner Mölders to name but two. In part this was because of the pairing system, with one man doing the principal shooting while the wingman watched his back. But it was also because all those men were excellent pilots and could get a performance from their Me 109Es that was significantly superior to anything the enemy could manage.

The other key factor was firepower. Both the Spitfire and Hurricane had eight machine-guns, four spread in each wing, that simultaneously fired 1,200 rounds per minute. The problem was that they only carried ammunition drums of 300 rounds, which meant they had just fifteen seconds’ worth of firing time. Most pilots found this was very quickly used up. The second problem was that to bring the full effect of these machine guns to bear, the target needed to be hit at the point at which the bullets all converged. And since most of these bullets were ordinary .303 that were the same size as those used in a Bren or a Lee Enfield rifle, on their own they did not pack that much of a punch. The advent of De Wilde incendiary ammunition improved matters a bit. ‘When it hit an aeroplane,’ says Tony Bartley, a pilot with 92 Squadron, ‘it flashed and you could see the flash as it hit, which was good.’ But De Wilde rounds only ever made up a small proportion of the bullets used. Air Chief Marshal Dowding, Commander of RAF Fighter Command, and the Air Ministry – and Lord Beaverbrook at the Ministry of Aircraft Production especially – had recognized that cannon-armed Spitfires were the way forward, but although some Spitfires had been trialled with cannons, jamming and seizure were recurring problems that had yet to be ironed out.

In contrast, both the Me 109E3 and E4 had two MG17 machine guns and two MGFF 20 mm cannons, one in each wing. The E4 had the MGFF/M, which fired a new and more powerful explosive shell. Both machine guns were mounted on the engine cowling so there was no need to worry about bullet convergence – a pilot simply pointed his plane at a target and fired. Each of these high-velocity machine guns had 1,000 rounds, that is, more than three times as many rounds as each of the Brownings used in the British fighters. Since the MG17s also had a slightly lower rate of fire, that meant German fighter pilots had around 55 seconds’ worth of ammunition, almost four times as much as their British counterparts. It was true that the cannons only had sixty rounds each, and that even though they had a far slower rate of fire they were worth just seven seconds of firing time. However, the cannon and machine gun had different firing buttons – a thumb button on the top of the control column grip fired the cannons, while a finger trigger fired the MGs – so could be used once the machine guns had already found their mark. And while just one 20 mm high-explosive cannon shell could mean instant destruction for a British fighter, it often took a lot more .303 bullets to shoot down anything, as 74 Squadron discovered when between them they fired 7,000 bullets at a Do17 and still failed to knock it out of the sky. Stand at 250 yards and fire a single .303 bullet into a piece of aluminium and the result is a neat hole. Do the same with a 20 mm cannon shell and a hole the size of a fist is the result. Add something on the other side against which the shell can explode and the mess is astonishing. Allan Wright, a British pilot in 92 Squadron, once saw a Spitfire hit by a German cannon shell. ‘The cockpit blew up,’ he says. ‘You could see the canopy disappear and presumably the bloke as well because there was such an explosion.’

Unsurprisingly, most pilots when asked which they would rather have, the German or British armament, opt for the cannon and machine-gun combination. ‘They had much more ammunition than we did,’ says Tom Neil, ‘and it was effective. Their cannon shells exploded.’ Pete Brothers agrees. ‘Cannon gave them a tremendous advantage,’ he says. ‘You certainly envied them their cannon.’

The Me 109 was thus a better fighter aircraft than the Spitfire in 1940, and a far superior one to the Hurricane. It has been endlessly pointed out that the Hurricane shot down more aircraft than the Spitfire in 1940, but there were much more of them than Spitfires, which makes this something of a false argument. Compare the profile view of the Hurricane with its biplane predecessors such as a Hawker Hart or Fury, for example, and the genealogy is immediately apparent. All three have almost identical fuselages, tail planes and cowlings. The fuselage of the Hurricane was also made of doped Irish linen like the earlier biplanes. Another big drawback of the Hurricanes and Spitfires was fuel tanks that had not been treated with any kind of flameproof sealant. This was partially remedied, as those in the wings were treated with a sealant called Linatax, but the reserve tank in the fuselage was left uncovered. The best that could be done for the large fuel tank sitting the other side of the instrument panel was to put up a metal bulkhead in between, but this was of limited value if the tank was punctured and started leaking fuel all over the pilot, while even with Linatax the wing tanks in the Hurricane were especially susceptible to flame, which, thanks to the draught caused by the gun holes, soon spread along the hollow wings and engulfed the cockpit. The problem was that once the cockpit was on fire, the pilot had seconds to get out, because opening the hood once the fire took hold only fanned the flames further. Many of those who did get out suffered horrific burns.

Hurricanes had their merits. They were a stable gun platform and certainly bullet holes through the fuselage were easy and quick to repair. They were also faster than all the German bombers and infinitely more manoeuvrable. Pete Brothers did everything he could to improve the performance of his Hurricane. He took the mirror off the top and bought a curved car mirror and had it fixed inside the windscreen, and when he was waiting to be scrambled, he and his rigger would often sit on the wing with a bit of sandpaper, filing down the pock rivets to help reduce the drag. ‘I reckon we got an extra seven miles per hour out of it,’ he says. ‘No-one else bothered but I thought it was worth doing and it gave me something to do on the ground.’

The Germans did have another fighter, in the Battle of Britain, however – one that is all too often discounted from any comparative analysis.  The twin-engine Messerschmitt 110 Zerstörers had greater firepower than any of the single-engine fighters and were faster than Hurricanes, which made them a dangerous opponent. Plenty of Spitfires and Hurricanes, especially, were shot down by Me 110s, although this did not hide their fundamental weakness as a fighter – their lack of manoeuvrability. The Zerstörer was another pet project of Göring, the Commander-in-Chief of the Luftwaffe, which, like the Stuka, was horribly shown up once they were confronted with half-decent single-engine fighters. Unlike the Stukas, the Zerstörers would continue to play a part in the battle, albeit a reduced one, but the losses of Me 110s were horrendous. Twenty-one were destroyed on 15 August, and a further thirteen three days later. Since Göring had puffed up the status of the Zerstörer units, its pilots were often both highly skilled and experienced.  The tactical short-sightedness with which Göring and his staff viewed the Zerstörers meant far too many potentially highly skilled pilots who might have been far better used in single-engine fighters were lost to the Luftwaffe.

In 1940, the Hurricane was at the end of its development cycle, the Me 109 was half way through, but the Spitfire was really still in its infancy.  By the war’s end, numerous other marks of this most famous of fighters had been developed and it became more than a match for anything Professor Messerschmitt could develop.  However, in the summer of 1940, the Me109E was king.  People can argue about turning circles and manoeuvrability until they are blue in the face, but the facts about the make-up of these differing fighters are indisputable.  Moreover, it is hard to argue against the judgement of those British test pilots flying all three fighters over Farnborough in May and June 1940.  This argument, should now, once and for all, be put to bed.

2 replies
  1. Eric
    Eric says:

    At what point did historians and the establishment fix beginning and end dates to the Battle of Britain. Looking at the night bombing of British cities during the winter of 1940 and spring of 1941, one can make a case for that period being the last phase of the battle. Any thoughts?

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