Spitfire Versus Messerschmitt Bf109 in 1940
The bulk of this essay was first published in 1992 as part of my "Spitfire!" hyperbook title for the Commodore Amiga computer, (it has been widely plagiarised since; whole paragraphs crop up on other websites without a word altered). I have updated it since, with details from work published since then. I do not mind people quoting this page - that's what it's there for - but an acknowledgement of the source and a link back to my website would be appreciated.
The Spitfire achieved fame in the Battle of Britain. It was seen as the aircraft that had saved Great Britain from Invasion. In fact, it was the Hurricane that bore the brunt of the Battle of Britain, equipping 32 Squadrons to the Spitfire's 19.
However, it was the Spitfire that gained the respect of the Luftwaffe, a force that was until then accustomed to having its own way.
The Spitfire and Hurricane were, in truth, a great team. The Spitfire had the performance and speed to take on the German fighters, and its widely spaced "blunderbuss" machine guns were ideal for fighter-v-fighter dogfights. The rugged, reliable Hurricane was available in numbers that ensured the RAF did not lose a battle of attrition. Its closely grouped machine guns were good for bringing down German bombers.
What of the Spitfire's opponent the Messerschmitt 109? Which was the better aeroplane? Some sources say the Spitfire was faster, others maintain it was the Messerschmitt that had the edge in speed. Some people have even said the Bf109 was more manoeuvrable. The Bf109 also had the advantage of a direct fuel-injection system for its engine, which meant it could do negative G manoeuvres that a Spitfire would have difficulty following (See the section on the Merlin engine). The 109 was also equipped with cannon armament, whereas the Spitfire had to make do with machine guns. Many armchair aviators have concluded that the Messerschmitt was the better design. However, the Spitfire is remembered as the victor, and rightly so...
We shall now look in more detail at the performance of both aircraft, remember that all figures refer to the Spitfire Mk I with Merlin III engine and the Messerschmitt Bf109E3/4 fitted with DB601A engine.
SPITFIRE Mk1 (Merlin III) = 355 MPH AT 18,500 feet. *
Bf 109E (DB601A) = 348 MPH AT 17,500 feet. *
You will no doubt see maximum speeds for the Spitfire quoted as being around 365 mph, this is without much of the equipment onboard a Spitfire would have carried into battle in 1940. Foremost amongst the extra weight was a sheet of armoured metal behind the pilot and an armoured windshield in front of him. Ask most Spitfire pilots what they would prefer, the armour or a few extra mph and most would plump for the armour. With armour fitted it was rare for the pilot of a Spitfire to be killed outright by the machineguns or low-velocity cannon of a 109E. With his Spitfire shot to bits around him, the Spitfire pilot could bale out or crash-land to fight another day. His biggest danger was his fuel tank catching fire or exploding. There was no problem with losing a Spitfire, British fighter production had been pushed to new heights in 1940. A Spitfire pilot would find a new aircraft waiting for him back at his airfield. It was pilots the British were short of in 1940, not aircraft.
Airspeed varies with height and both the Spitfire and Bf 109 achieved their best speeds in the band between 15 and 25 thousand feet. The Spitfire maintained a slight speed advantage over the standard Bf109 (with DB601A engine) at both higher and lower altitudes. The situation was changed by the DB601N engine in the Bf109E-4N model that started to be introduced during July 1940. This gave an increased performance, particularly at high altitude. It also had provision for the injection of nitrous oxide to further boost performance at altitude. The DB601N had reliability issues and had only half the operating life of the earlier DB601A engine, so it was introduced into service in only small numbers at first but as 1940 wore on it became more prevalent and the Bf109s started to operate at higher and higher altitudes to make the best use of its performance (the later Bf109E-7 model also used the DB601N engine). In the same time-frame, the RAF introduced the Spitfire Mk II with the Merlin XII engine, which went some way to redress the balance.
The rates of climb of the Spitfire I and Bf109 with DB601A engine were almost identical. However, the Bf109 could climb at a higher angle than the Spitfire (albeit at a lower forward speed). A skilled German pilot could use this ability to disengage from combat.
The first Spitfires to be delivered had two-bladed fixed-pitch propellers, and later three-blade two-position propellers. Just before the Battle of Britain both Spitfires and Hurricanes were quickly modified with constant-speed propellers. This greatly increased the performance of the engine and decreased the workload of the pilot. The Bf109 also used propellers with an adjustable prop angle, there were two different methods of control, depending on the mark of aircraft, one of the versions took some time and practice to master.
A Spitfire pilot will tell you the Spit could turn inside the 109. Some Messerschmitt pilots were unshaken in their belief that the 109 could turn inside the Spitfire! Both designs were capable of turning circles that would cause the pilot to "black-out" as the blood drained from the head. The pilot who could force himself to the limits without losing consciousness would emerge the victor from a turning battle, and the Spitfire pilots had supreme faith in their machine. The British popular press (and even one broadcast by the BBC early in the war) told them that the wings came off the 109 in a dive or tight turns, untrue but possibly based on some early wing failures in the 109's predecessor the Bf108. British designers and aeronautical pundits also found the Bf109's wing structure somewhat strange, with only two attachments between the wing and fuselage and their suspicions that this might prove fragile in combat probably influenced the popular press comments.
The Spitfire had a lower wing loading than the Bf 109 and this would normally give the better turning circle. However the 109 had help with its leading-edge slats which gave a lower stalling speed, and thus was able to turn tighter than a simple comparison of wing areas might suggest. The 109 was very forgiving if stalled, with little tendency for a stall to develop into a spin, something that could happen to a Spitfire, although the Spitfire gave its pilot plenty of warning that he was approaching a stall due to the slight twist in the wing known as "wash-out". It is this "wash-out" that probably holds the key to the Spitfire's success. Because of the twist to the wings the stall (break up in airflow over the wing) would develop first near the fuselage rather than at the tip as on most conventional "straight" wings. This manifests itself as feedback to the pilot through the controls and the airframe, in effect the Spitfire "talks" to the pilot and tells him he must ease back on the stick to avoid stalling completely. Because the airflow at the tips of the wings (where the control surfaces are) is still stable the controls are still effective. In a tight combat turn with minimum turning circle, the aircraft is always on the edge of stalling, the feedback the Spitfire gave its pilot is probably the crucial factor in a turning battle.
There is more than one account by German wartime fighter pilots that suggest that many Luftwaffe novices did not use the turning performance of the 109 to the full. They seem to have regarded the point at which the automatic slats popped out as being a warning to ease back. Only more experienced pilots pushed the Bf109 to its limits. The way the slats operated could itself be a problem, causing the Bf109 to "buck" and throw off the aim of the Bf109 pilot, perhaps at the critical moment. The slats could also operate asymmetrically if flown into the slipstream of another aircraft, again making aiming difficult.
Both the Spitfire and Messerschmitt became harder to control at high speeds, with greater and greater strength needed on the control column as the speed increased.** However the problem was much worse in the Messerschmitt and in the high-speed fights that developed in the Battle of Britain the Spitfire had the advantage. The Messerschmitt's elevator control was very heavy at high speed and there are reports that Spitfire pilots would escape from 109s by diving towards the ground and pulling up at the last moment knowing that the German would find it much harder to pull back on the stick to escape destruction. The Spitfire was capable of being pulled out of a dive with such high "g" forces that the pilot would blackout (for only a second or so), meaning the pilot, not the aircraft, was the limiting factor, this is how it should be for a fighter. The Messerschmitt's heavy elevator control at high speed meant that a German pilot would not be able to pull enough "g" to blackout, meaning the aircraft itself was the limiting factor.
This brings us to the control column; the small cockpit of the Bf109 allowed only a very small area of travel for the stick, only 4 inches. Nowadays, with powered controls, this would be seen as an advantage (like the small steering wheel in a racing car), but in 1940 pilots used sheer muscle-power to haul their aircraft around the sky. The cramped cockpit of the 109 meant that its pilot could employ only a fraction of his strength on the control column. Meanwhile, the more spacious Spitfire allowed more elbow room for its pilot to wrestle with the control column, which was topped by a large spade type grip so that the pilot could use both hands.
The rate of roll of the Messerschmitt was inferior to the Spitfire at high speed. Since you have to roll before you can get into a turn this gave the Spitfire pilot another advantage at the start of any turning dogfight at high speed.
Thus it can be seen that if a Spitfire pilot could keep the speed of the dogfight high he held a distinct advantage in manoeuvrability.
Two very different appraisals of the turning circles of the Spitfire and Bf109 can be found in the books "Fighter" by Len Deighton and "The Most Dangerous Enemy" by Stephen Bungay. The former has a diagram showing the Bf109s turning circle to be inside that of the Spitfire (750 feet and 880 feet respectively) while the latter has a diagram showing the opposite (850 feet and 700 feet respectively). Crucially all the tests of mock combats between captured Bf109s and Spitfires always give the Spitfire the edge.
Diving and "Negative-G".
The most well-known advantage of the Bf109 was its ability to pull "negative-g" manoeuvres. Because its engine had direct fuel injection the engine would continue to work. Meanwhile, both the Spitfire and Hurricane's Merlin engines used a conventional float-carburettor, which would flood and starve the engine of fuel if negative-g manoeuvers were tried. Thus a Bf109 could leave its opponents behind by "bunting" over into a dive. However, this fact is rather overplayed in descriptions of the German fighter. The Bf109E accelerated in a dive much more quickly than either the Spitfire MkI or Hurricane MkI and would rapidly leave them trailing behind. Thus, a dive away would still have been a standard escape tactic for any Bf109 E pilot even if the fuel-injection advantage had not existed. British pilots tried to counter the negative-g effect by rolling their aircraft inverted to follow the Bf109 into a dive. That way the force on the carburettor float acted in the opposite direction and the Merlin engine continued to give full power. After the Battle of Britain, in March 1941, Spitfires and Hurricanes were fitted with a simple device devised by Beatrice Shilling at the Royal Aircraft Establishment which prevented the carburettor from flooding from short applications of negative-g. This served as a stop-gap until the introduction of Bendix pressure carburettors in 1943. However, the Bf109F could still outstrip the contemporary Spitfire MkV in a dive. It was the introduction of the Spitfire Mk IX that gave the RAF an aircraft that could keep up with a BF109F or G in a dive, while the Griffon-engined Mk XIV could overtake them.
The combined effect of the Bf109's advantage in diving, and also its ability to climb more steeply, gave it an advantage in the vertical plane. Thus the Bf109 was best at diving attacks. Meanwhile, the Spitfire (and Hurricane) held the advantage in the horizontal plane. If the encounter developed into a turning dogfight the British fighters held the advantage, even more so if that dogfight took place at high speed.
The Spitfire had eight Browning machine guns spread out along the wing. These each had 300 rounds of normal bullets, tracer, incendiary or armour-piercing (the last type only effective against the thinnest of armour). The guns were configured so that the bullets converged on a single point some distance in front of the aircraft. At first, this distance was over 400 yards, however, pilots soon found that the best results were obtained if they made it 250 or 200 yards instead. The use of eight machine guns meant that even the novice fighter pilots thrown into the battle by the British had a chance of hitting something if they could get into firing position. On the other hand, the 109`s armament favoured the marksman. The 109 had two machine guns of similar performance to the British Brownings, but mounted in the nose and synchronised to fire through the propeller. These had magazines of 1,000 rounds each, which meant the German could keep his finger on the trigger over three times longer than his British counterpart, but after that time he would have still expended 400 fewer rounds than the Spitfire pilot. The Messerschmitt was also equipped with two 20mm cannon, but they had a low velocity, poor rate of fire and only 60 rounds per gun****. Against British bombers they were devastating, but the manoeuvrable and swift Spitfires and Hurricanes were a difficult target.
The incendiary bullets used by the British in the Battle of Britain gave the RAF a great advantage. They could cause the fuel tank of a target aircraft to explode and the flash of light they gave off showed the British pilot his bullets were striking home. The incendiary bullet had been developed in secret at Woolwich Arsenal and was only just ready in time for the Battle of Britain. Named "de Wilde" ammunition by the British this was a ruse to make the Germans think it was based on the work of a Mr de Wilde in Switzerland. In fact, it had been found that "proper" de Wilde bullets could only be made by hand, whereas the British design could be mass-produced. The British "de Wilde" bullets were the invention of C. Aubrey Dixon, a Captain in the Bedfordshire and Hertfordshire Regiment (he retired with the rank of Brigadier), one of the unsung heroes of the Battle of Britain.
Spitfire armament progressed throughout the war. Firstly, two 20mm cannon replaced four of the wing-mounted machine guns. Then the remaining rifle calibre machine guns were replaced with a pair of large calibre machine guns with longer range. Finally, like all British single-seat fighters at the end of the war, the Spitfire had a total of four 20 mm cannon.
The Spitfire cockpit canopy afforded its occupant a better view than the Bf109. The bulged canopy had not been fitted to improve vision, it was to stop pilots bumping their head when taxiing over rough ground! The Messerschmitt canopy, on the other hand, was box-like, with lots of framework to impede the view. It did have a couple of good points, it had a very good "clear view" panel that was not obscured by rain or oil thrown back from the engine, and it was made of a better quality of Perspex than the Spitfire's, which was prone to scratches. The Spitfire canopy could be slid back for a better view while taxiing and during takeoff. This was impossible in the 109 due to the canopy hinging to the side. However, the Bf109's pilot position was further forward than that of the Spitfire, this gave the Bf109 pilot a better view downwards over the leading edge of the wings. The fact that the nose of the Bf109 curved downwards (because of the engine being an inverted "V" layout) also gave the Bf109 pilot a better view directly forward, this could be of great use in deflection shooting in a turning fight. This advantage was lost with the introduction of the "beule" blisters over the breech blocks of the 13mm machine guns on the Bf109G series..
The Spitfire and Bf109 were very evenly matched in terms of pilot protection. Armour plating behind the pilot was added to both designs early in the war. The difference in the position of the fuel tanks between the two aircraft is interesting. The Spitfire had the fuel tanks in front of the pilot, between the engine and the cockpit. This meant the armour to the rear of the cockpit gave a degree of protection to the fuel tank from fire from behind. However, if the tank was punctured or set afire it meant the fuel and flames were blown back into the cockpit, giving rise to the horrific burns suffered by many British fighter pilot casualties. The pilot of the Bf109 had the fuel tank behind and below him. Sitting on a fuel tank may seem far from the ideal situation, yet the fuel tank could give the Bf109 pilot added protection, any bullets that entered the fuel itself would often be stopped by the liquid. Only if an incendiary bullet entered the vapour filled area above the fuel would there be an explosion. Any flames or fuel from a holed Bf109 fuel tank would be blown back by the slipstream away from the pilot.
The two machines had similar outward retracting undercarriages of narrow-track. The 109's was always a source of problems and a large number of 109's were damaged or written-off due to landing accidents and undercarriage faults. It was not the narrow track of the 109 alone that caused the problem (the Spitfire had an even narrower-track undercarriage but did not suffer the same issues), rather it was the narrow-track combined with long stalky legs with the aircraft wheels raked out at a "negative camber angle" that produced an overall configuration that demanded very precise handing on take-off and landing and that was easily damaged by a heavy landing. The landing characteristics of the 109, with its leading-edge slats, were different to standard aircraft and could take some getting used to.**** On the other hand, German pilots who flew captured Spitfires on test (Werner Molders for example) could hardly believe how "childishly simple" the Spitfire was to fly and land.
AS A WEAPONS SYSTEM
The two aircraft were very evenly matched. Victory went to the best pilot, or the one who had the height advantage or just saw his opponent first. In this respect, the Spitfire pilot had the advantage of being part of a much wider weapons system. The Spitfire was linked by radio to control centres that could monitor the battle with Radar. This control could place the Spitfire squadrons where they were needed most. The British strategy and disposition could be changed at a moments notice, while the German plans were effectively unable to be changed when their aircraft left the ground. The use the Germans made of their excellent radio sets was crude compared to the British. There are even stories that in 1940 high ranking Luftwaffe officers such as Adolf Galland wanted all radio equipment deleted from the Bf109 to save weight!
AFTER THE BATTLE OF BRITAIN
When the Battle of Britain ended the RAF was starting to receive Spitfire MkIIs with increased performance. This was countered on the German side by the increased availability of the Bf109E-4N and then the Bf109F. The Bf109F outclassed the Spitfire Mk I and II but was then, in turn, countered in early 1941, by the Spitfire Mk V although the Bf109F retained a slight edge, a margin widened by the later F3 and F4 models. The arrival, in late 1941, of the Focke Wulf FW 190 gave the Germans an aircraft that could comprehensively out-perform the Spitfire at all but high altitude. The FW 190 was then countered by the Spitfire MK IX and Griffon engined Mk XII, both of which also outclassed the Bf109G. The long-nosed FW 190 D series and late-war Bf109K were countered by the two-stage Griffon engined Spitfire Mk XIV.
The Spitfire was kept for home defence until the danger of Invasion had largely passed. From 1941 onwards they were released for service elsewhere. Over a thousand were given to the Americans and many went to Russia. In the far east, they served against the Japanese where they found a worthy adversary in the A6M "Zero" long-range fighter that, like most Japanese fighters, excelled in manoeuvrability. To fight it Spitfire pilots had to adopt a "slash and run" policy and use their superior speed and diving superiority to fight, and avoid being drawn into dogfights; very much a reversal of the Spitfire's tactics in the Battle of Britain.
An epic chapter in Spitfire history was in the defence of Malta. Flown off aircraft carriers or flown from Gibraltar with enormous "slipper" fuel tanks underneath, the Spitfire helped to fend off the attacks on the brave island by the Luftwaffe and Regia Aeronautica. In the Western Desert, Spitfires arrived quite late but found themselves doing good work as the Allies took all the southern shore of the Mediterranean and then attacked Sicily and Italy. The Spitfires began to carry bombs to harass the enemy ground forces. Three bombs could be carried, up to a total of 1,000 lbs.
It was here that the Spitfire met the Macchi c202 Folgore, powered by a licence-built version of the DB601 engine. Its designer had built the Italian seaplanes that had raced against Mitchell's S5 and S6 in the Schneider trophy. The Macchi had the rakish lines of a thoroughbred, but it went to war with an inadequate armament of only two machine guns and failed to stem the tide of Allied victor.
The Spitfire was, and is, to many pilots the ultimate fighter and flying machine. All who flew her loved her, and it will be a sad day indeed if there ever comes a time when there is no example of RJ Mitchell's immortal fighter able to take to the air and be at home amongst the clouds.
* In the various sources I have consulted the maximum speeds of the Spitfire and Bf109 quoted vary from 346 to 365 mph for the Spitfire Mk I and from 345 to 357 mph for the Bf109E. It is worth noting that when the Germans tested captured Spitfires they used their own lower octane fuel, and not the 100 octane fuel used by the RAF. This meant the Germans recorded a lower performance in their tests, perhaps lulling them into a false sense of technical superiority. Their initial tests were also done on a Spitfire without a constant-speed propeller, again blinding them to the Spitfire's full potential.
**It was later found that the fabric-covered ailerons of the Spitfire caused the increase in force needed on the control column due to the bulging of the fabric at high speed. When metal covered ailerons were fitted the handling of the Spitfire at high speed improved greatly. Unfortunately, this discovery did not take place in time to help British pilots in the summer of 1940.
*** The MG FF Cannon used in the Bf109E was a development of a Swiss design. It had a muzzle velocity of only 580 metres per second (compared to 870 metres per second for the British built Hispano cannon) which meant it lacked the range and penetration of the British weapon. Also, the shells of the MG FF would detonate as soon as they contacted the airframe of the target and hence would often not penetrate any armour.
****A telling insight into how traumatic the first flight in a Bf109 could be is conveyed in Heinz Knoke's book "I flew for the Fuhrer".