Dinger's Aviation Pages
Spitfire Versus Messerschmitt Bf109 in 1940
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. The more easily produced Hurricane ensured the RAF did not lose a battle of attrition. However, it was the Spitfire that gained the respect of the Luftwaffe, a force that was until then accustomed to having its own way.
What of the Spitfire's opponent the Messerschmitt Bf109? 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. 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.
What of the Spitfire's opponent the Messerschmitt Bf109? 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. 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.
SPEED
SPITFIRE MkI (Merlin III) = 355 mph (571 kph) at 18,500 feet (5,639 metres). ¹
Bf 109E (DB601A) = 348 mph (560 kph) AT 17,500 feet (5,334 metres). ¹
You will no doubt see maximum speeds for the Spitfire Mk I quoted as being around 365 mph (587 kph), 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 machine guns 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. (4,570 to 7,620 metres) 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 Mk I and Bf109E with DB601A engine were almost identical. Interestingly, British testing of a captured Bf109 said it could climb at a higher angle than the Spitfire (albeit at a lower forward speed). German tests of a captured Spitfire seemed to show exactly the opposite result! It may be that the German evaluation result was the result of them testing a Spitfire with a two-position propeller, rather than a constant-speed propeller. In which case, the advice they gave to their pilots to adopt a shallow angle of climb to escape a pursuing Spitfire, was completely wrong!
The British had the advantage of using 100 octane fuel, which allowed the use of 12 lb boost on the engine, which greatly increased speed for short periods. The RAF had started trials on using 100 octane fuel from as early as 1937, but held off adopting it for all fighter squadrons until they could be sure of adequate and continuing supplies (mostly from the USA). Large reserves of the fuel had been built up at all UK fighter stations by March 1940, so existing Spitfires and Hurricanes started to be modified to be able to use it. At the same time, new Merlin engines coming off the Rolls-Royce production lines were also built to be able to use 100 octane fuel. By the time of Dunkirk, very few (if any) Spitfires would have been using the earlier 87 octane fuel, and by the start of the Battle of Britain all operational Spitfire and Hurricane squadrons were using it. The Germans only used 87 octane fuel during the Battle of Britain period. Later in the war, they developed their "C3" fuel, which gave an increased performance, but was always in short supply.
The first Spitfires to be delivered had two-bladed fixed-pitch propellers and later three-blade two-position propellers. In the first month of the Battle of Britain, many Spitfires and Hurricanes were quickly modified with automatic constant-speed propellers. This greatly increased the performance of the engine and decreased the workload of the pilot. Work to change over to constant-speed propellers started on 22nd June 1940, with some sources reporting that all operational Spitfires and Hurricanes had been converted by 16th August. However, there is some doubt about this, because the first Spitfire captured largely intact by the Luftwaffe (N3277 that crash-landed near Cherbourg) was only the day before, 15th August, and that still had a two-pitch manual propeller. Reports of mock combats between various Spitfires and a captured Bf109E show that some of the Spitfires still had two-position manual propellers in September 1940. Many of the Bf109s in the Battle of Britain only had propellers with a manually adjustable prop angle. While this did allow finer control than the two-position controls used by the British, it still enormously increased the workload of the pilot. On some of these Bf109s, the propeller control was mounted on the instrument panel, which was hard to manipulate in a dogfight; on other Bf109s, the control was moved to the throttle quadrant. A constant-speed propeller system was introduced on the Bf109 E production lines, but the ratio of Bf109Es with this new system to those with the older manual system during the Battle of Britain period is debated. The RAF seemed to be surprised to find a constant-speed propeller on the Bf109 F when they evaluated their first captured example.
Airspeed varies with height and both the Spitfire and Bf 109 achieved their best speeds in the band between 15 and 25 thousand feet. (4,570 to 7,620 metres) 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 Mk I and Bf109E with DB601A engine were almost identical. Interestingly, British testing of a captured Bf109 said it could climb at a higher angle than the Spitfire (albeit at a lower forward speed). German tests of a captured Spitfire seemed to show exactly the opposite result! It may be that the German evaluation result was the result of them testing a Spitfire with a two-position propeller, rather than a constant-speed propeller. In which case, the advice they gave to their pilots to adopt a shallow angle of climb to escape a pursuing Spitfire, was completely wrong!
The British had the advantage of using 100 octane fuel, which allowed the use of 12 lb boost on the engine, which greatly increased speed for short periods. The RAF had started trials on using 100 octane fuel from as early as 1937, but held off adopting it for all fighter squadrons until they could be sure of adequate and continuing supplies (mostly from the USA). Large reserves of the fuel had been built up at all UK fighter stations by March 1940, so existing Spitfires and Hurricanes started to be modified to be able to use it. At the same time, new Merlin engines coming off the Rolls-Royce production lines were also built to be able to use 100 octane fuel. By the time of Dunkirk, very few (if any) Spitfires would have been using the earlier 87 octane fuel, and by the start of the Battle of Britain all operational Spitfire and Hurricane squadrons were using it. The Germans only used 87 octane fuel during the Battle of Britain period. Later in the war, they developed their "C3" fuel, which gave an increased performance, but was always in short supply.
The first Spitfires to be delivered had two-bladed fixed-pitch propellers and later three-blade two-position propellers. In the first month of the Battle of Britain, many Spitfires and Hurricanes were quickly modified with automatic constant-speed propellers. This greatly increased the performance of the engine and decreased the workload of the pilot. Work to change over to constant-speed propellers started on 22nd June 1940, with some sources reporting that all operational Spitfires and Hurricanes had been converted by 16th August. However, there is some doubt about this, because the first Spitfire captured largely intact by the Luftwaffe (N3277 that crash-landed near Cherbourg) was only the day before, 15th August, and that still had a two-pitch manual propeller. Reports of mock combats between various Spitfires and a captured Bf109E show that some of the Spitfires still had two-position manual propellers in September 1940. Many of the Bf109s in the Battle of Britain only had propellers with a manually adjustable prop angle. While this did allow finer control than the two-position controls used by the British, it still enormously increased the workload of the pilot. On some of these Bf109s, the propeller control was mounted on the instrument panel, which was hard to manipulate in a dogfight; on other Bf109s, the control was moved to the throttle quadrant. A constant-speed propeller system was introduced on the Bf109 E production lines, but the ratio of Bf109Es with this new system to those with the older manual system during the Battle of Britain period is debated. The RAF seemed to be surprised to find a constant-speed propeller on the Bf109 F when they evaluated their first captured example.
MANOEUVRABILITY
A Spitfire pilot would tell you the Spit could turn inside the Bf109. Some Messerschmitt pilots were unshaken in their belief that the Bf109 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, particularly the way the wings were designed to be easily removed, 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, but if they did so, a stall could occur without any warning. 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. The operation of the slats would also slow down the Bf109; in a turning dogfight with a Spitfire the Bf109 could find itself falling behind in the turn if the slats were in operation. Meanwhile, the clean wings of the Spitfire would enable it to retain energy and speed.
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, but if they did so, a stall could occur without any warning. 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. The operation of the slats would also slow down the Bf109; in a turning dogfight with a Spitfire the Bf109 could find itself falling behind in the turn if the slats were in operation. Meanwhile, the clean wings of the Spitfire would enable it to retain energy and speed.
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.² 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. In extreme fast dives, 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 Bf109 pilot's seat was slightly reclined, meaning the pilot could withstand more "g" forces before blacking out. This was noticed during the testing of the first captured Bf109 in 1939. In response, the British designed rudder bars with two steps, so that the pilot could raise his feet higher to better withstand "g" forces. These were tested with success by Robert Stanford Tuck (then a Flight Lieutenant) in July of 1940. They were introduced on both the Hurricane and Spitfire production lines straight away and retrofitted to existing aircraft. By the end of the Battle of Britain, most operational Spitfires had them fitted. ³
While the rate of roll of the Messerschmitt Bf109E was better than the Spitfire at low speed, they were identical at about 300mph and the Spitfire was superior at speeds above that. 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. Controversially, Deighton has a diagram showing the Bf109s turning circle to be inside that of the Spitfire (750 feet and 880 feet respectively), while Bungay has a diagram showing the opposite (850 feet and 700 feet respectively). Deighton's figures have since been discredited. Crucially, all the tests of mock combats between captured Bf109s and Spitfires always give the Spitfire the edge in turning.
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 Bf109 pilot's seat was slightly reclined, meaning the pilot could withstand more "g" forces before blacking out. This was noticed during the testing of the first captured Bf109 in 1939. In response, the British designed rudder bars with two steps, so that the pilot could raise his feet higher to better withstand "g" forces. These were tested with success by Robert Stanford Tuck (then a Flight Lieutenant) in July of 1940. They were introduced on both the Hurricane and Spitfire production lines straight away and retrofitted to existing aircraft. By the end of the Battle of Britain, most operational Spitfires had them fitted. ³
While the rate of roll of the Messerschmitt Bf109E was better than the Spitfire at low speed, they were identical at about 300mph and the Spitfire was superior at speeds above that. 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. Controversially, Deighton has a diagram showing the Bf109s turning circle to be inside that of the Spitfire (750 feet and 880 feet respectively), while Bungay has a diagram showing the opposite (850 feet and 700 feet respectively). Deighton's figures have since been discredited. Crucially, all the tests of mock combats between captured Bf109s and Spitfires always give the Spitfire the edge in turning.
"Before turning fights with the Bf 109 E type, it must be noted in every case, that
all three foreign planes have significantly smaller turning circles and turning times."
all three foreign planes have significantly smaller turning circles and turning times."
From official German test report on evaluation of a Spitfire, Hurricane and Curtiss P-36.
"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. 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 stopgap until the introduction of Bendix pressure carburettors in 1943.
It should be stressed that in 1940, "negative-g" was not just an issue for the engines of the Spitfire and Hurricane, it affected the fighters of almost every other nation in the world, the Poles; French, Dutch, Belgian and Soviet fighters all used float carburettors. Even the earlier A, B & D marks of the Messerschmitt Bf109 had used Jumo engines with float carburettors. Most US aircraft also used float carburettors although they were just starting to adopt the Bendix pressure carburettor which did not have the issue.
ARMAMENT
The Spitfire had eight Browning machine guns spread out along the wing. These each had between 300 and 350 rounds of normal bullets, tracer, incendiary or armour-piercing (the last type only effective against the thinnest of armour) giving up to 18 seconds of firing time. 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 (360 metres), however, pilots soon found that the best results were obtained if they made it 250 (230 metres) or 200 yards (183 metres) 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 MG 17 machine guns of similar performance to the British Brownings, but mounted in the nose and synchronised to fire through the propeller. The guns were slightly staggered, so that each of their ammunition magazines could take up the full fuselage cross section. These magazines each held 1,000 rounds, which meant the German could keep his finger on the trigger three times longer than his British counterpart. Two thirds of the Bf109s used in the Battle of Britain were also equipped with two 20mm cannon, but they had a low velocity, poor rate of fire and only 60 rounds per gun.⁴ Against British bombers they were devastating, but the manoeuvrable and swift Spitfires and Hurricanes were a difficult target.
There is a mistaken assumption that all the Bf109s used in the Battle of Britain had cannons. Around a third of the Bf109s used in the Battle were of the E-1 variant with an armament of just 4 machine guns. The two rifle-calibre machine guns in the wings had 500 rounds of ammunition each. Even towards the end of the Battle, around a third of the replacement Bf109s being supplied were refurbished E-1s that had machine gun armament. Their use actually seemed to increase during the Autumn of 1940 when the E-1B conversion, able to carry a bomb, was used for "tip and run" attacks on targets in the south of England.
There is a mistaken assumption that all the Bf109s used in the Battle of Britain had cannons. Around a third of the Bf109s used in the Battle were of the E-1 variant with an armament of just 4 machine guns. The two rifle-calibre machine guns in the wings had 500 rounds of ammunition each. Even towards the end of the Battle, around a third of the replacement Bf109s being supplied were refurbished E-1s that had machine gun armament. Their use actually seemed to increase during the Autumn of 1940 when the E-1B conversion, able to carry a bomb, was used for "tip and run" attacks on targets in the south of England.
Bf109 E-1 of 2/JG52 shot down during1940. The lack of cannons protruding from the front of the wings show it to have only machine gun armament. A third of the Bf109s used in the Battle of Britain lacked cannon armament. Although they only had four machine guns compared to the Spitfire and Hurricane's eight, the Bf109 carried more ammunition. The British had 350 rounds per gun, 2,800 rounds in total, while the Bf109 had a 1,000 rounds for each fuselage gun and 500 rounds for each wing gun, a total of 3,000 rounds.
One interesting difference between the British and German machine guns used in the Battle of Britain was the type of ammunition belt used. The British had belts made of metal clips that fell apart as the ammunition was used. Thus on the Spitfire and Hurricane the bits of belt were discarded with the used cartridges in flight. The German MG 17 machine gun used a flexible metal belt (the "Gurt 17") that stayed intact. So the Bf109 had to have voids into which the used belt could be fed, to bring it home with the aircraft.
The incendiary bullets used by the British in the Battle of Britain gave the RAF a great advantage. They could cause the fuel tank or oxygen cylinder of a target aircraft to explode or catch fire, 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.
Informative video on the early adoption of the 20mm Cannon on the Spitfire on the Fired Up! Youtube channel.
Article on British aircraft gun armament in WW2.
Article on Bf109 armament changes during WW2.
VISION AND CANOPY
Article on British aircraft gun armament in WW2.
Article on Bf109 armament changes during WW2.
VISION AND CANOPY
In most directions, the Spitfire cockpit canopy afforded its occupant a better view and more freedom of head movement than that of the Bf109. The bulged top of the canopy had not been fitted to improve vision; it was to stop pilots bumping their heads when taxiing over rough ground! The Messerschmitt canopy, on the other hand, was box-like and cramped, with extensive framework that impeded the view. However, the Bf109 canopy was made of a better quality of Perspex than the Spitfire's, which was prone to scratches. The Bf109 had a "clear view" panel that could used if the front windscreen was obscured by rain, ice or condensation or oil thrown back from the engine, while the Spitfire made do with a smaller "punch-out" panel on the port side of its canopy. The Spitfire canopy could be slid back for a better view while taxiing and during takeoff, or if the front windscreen was obscured. 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 slightly 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 slightly better view directly forward, which could be of 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. Late in the war, the blisters were done away with by the adoption of the "Type 110" engine cowling that was slightly asymmetrical.
Neither the Spitfire nor Bf109 in the Battle of Britain had a particularly good view to the rear. From October 1941, the rearward vision of the Spitfire was improved by the introduction of the "Malcolm Hood", a canopy with a circular cross-section that allowed the pilot to turn his head more, to look back along the side of the aircraft. Towards the end of the war, a full "teardrop" canopy was introduced on the Spitfire, giving even better all-around vision. The vision from the Bf109 was slightly improved by the "Erla" canopy (commonly called the "Galland Hood") late in the war.
During the Battle of Britain, the Bf109 had one big advantage in that the entire canopy (and the rear fenestration and radio aerial) could be jettisoned to allow the pilot to bale out. The Spitfire pilot had to push his canopy back on its runners to bale out, and if these were damaged then he could find himself trapped in his cockpit. The most famous instance of this happening was to Richard Hillary, described in the first chapter of his book "The Last Enemy". The firm of Martin Baker came up with a mechanism to allow the Spitfire's hood to be jettisoned. This was introduced on the Spitfire Mk V production line in 1941 and retrofitted to the earlier Spitfires.
PROTECTION
Armour plating behind the pilot was added to the Spitfire early in the war, and all Spitfires in the Battle of Britain would have had this protection. Armour protection on the Bf109 was introduced in the late E3 model and made standard on the E4. It was retrofitted to earlier aircraft. However, many of the E1 model, which made up a third of the Bf109s used in the Battle of Britain, are shown in photoraphs not have armour behind the pilot. Both the Spitfire and Hurricane had a slab of "bulletproof" glass on the front windscreen. This was essential for stopping the rifle-calibre bullets from the gunners on German bombers. During the Battle of Britain, a bulletproof windscreen was not a standard fitting on Bf109s; even the later Bf109F model did not have it as standard. Later in the war, a bullet-proof windscreen became essential for the Bf109 if it was to attempt attacks on American bombers, and a slab of bullet-proof glass was added behind the pilot. 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.
UNDERCARRIAGE
The two machines had similar outward retracting undercarriages of narrow-track. The Bf 109's was always a source of problems and a large number of Bf109's were damaged or written-off due to landing accidents and undercarriage faults. It was not the narrow track of the Bf109 alone that caused the problem. The Spitfire Mk I had a narrower track undercarriage of only 1.75 metres compared to the 2 metres of the Bf109, 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 precise handling on take-off and landing and that was easily damaged by a heavy landing. The negative camber angle of the wheels of the Bf109 was a particular disadvantage on rough airstrips (positive camber is usually used on "bush" aircraft designed to be flown off uneven surfaces). The landing characteristics of the 109, with its leading-edge slats, were different to standard aircraft and could take some getting used to.⁵ 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.
The photo on the left shows the spindly, splayed legs and negative camber angle wheels of a Bf109 (actually it's a Hispano Buchon, but the undercarriage configuration is the same). On the right, you can see the shorter, upright legs and wheels of a Spitfire.
COCKPIT INSTRUMENTS
The Spitfire and Hurricane had an advantage over the Bf109 during the Battle of Britain period in both being fitted with a gyro-stabilised artificial horizon. This enabled them to climb or descend through cloud safely without getting disoriented. This made it much easier to carry out interceptions of German formations coming over above cloud cover and could be of use if attempting to escape a pursuer by entering cloud. It was also crucial to the Spitfire's use as a night fighter. Bf109 pilots had to rely on more basic turn-and-bank indicators. Later in the war, the Germans fitted artificial horizons into both the Bf109 and Fw190, essential for engaging Allied bombers coming in above cloud cover and for use in nighttime "Wilde Sau" operations.
OXYGEN EQUIPMENT
For operations at high altitude, the provision of an oxygen supply was essential. Both the Germans and the British used high-pressure oxygen cylinders that could explode or burn fiercely if penetrated and ignited by explosive or incendiary bullets or cannon shells. The Bf109 and Spitfire carried approximately the same amount of oxygen, but the Germans had the advantage of a regulator system that only supplied oxygen into a closely-fitting rubber facemask when the pilot breathed in. The British system supplied a continuous stream of oxygen into a loose fabric mask, meaning the oxygen supply ran out much more quickly. This could cause British pilots to cut short their missions or have to head for a lower altitude, perhaps putting them at a tactical disadvantage at times. The British adopted the "Puffing Billy" oxygen regulator at the end of September 1940, with it being fitted to all new production Spitfires and retrofitted to existing ones.⁶
TACTICS
There is no doubt that the British formation tactics lagged behind those of the Luftwaffe. The Spanish Civil War had given the Germans the opportunity to refine their fighter battle formation into the "Shwarm".<Click here to read an article on German fighter tactics>. The RAF flew in tight "Vic" formations and initially used a series of inflexible "Attack Plans" that had been designed on the assumption that German bombers would not be escorted by fighters. Although individual RAF squadrons experimented with different formations during the Battle of Britain, it was not until 1941 that they began to adopt the "Finger Four" which was close to the German swarm formation.⁷ There is a persistent myth that RAF Spitfires took on German fighters while the Hurricanes concentrated on German bombers. This was not true, there was no way British fighter controllers could distinguish between German fighter and bomber formations. RAF squadrons just took on German forces in an ad-hoc basis. It is true that the Hurricane's steadier firing platform and closely grouped machine guns were marginally better at bringing down German bombers, while the Spitfire's widely-spaced "blunderbus" guns were slightly more effective at scoring hits on wildly manouvering German fighters, but that does not mean either type of British fighter was deliberately vectored onto specific German formations.
During the Battle of Britain, number 12 Group of Fighter Command adopted the "Big Wing" tactic, with three Hurricane and two Spitfire squadrons flying together. They hoped to score decisive victories against the Luftwaffe by flying in this larger formation. Controversy still surrounds the use of this tactic. Most historians think that the extra time needed to assemble the Big Wing meant it was always late to deploy, and that it was unwieldy in action. However, there are a few pundits who disagree with this assessment. It was certainly a surprise to the Germans to encounter large numbers of British fighters at a time when their intelligence service assured them the RAF was on its last legs.
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, by pinpointing the position of British fighters using the "Pip-Squeak" radio system and by reports from the Observer Corps. This control could place the Spitfire squadrons where they were needed most. The British strategy and disposition could be changed at a moment's notice, while the German plans were effectively unable to be changed when their aircraft left the ground. The high-frequency (HF) radios carried by the Spitfire and the Bf109 (the TR9D radio in the Spitfire and the Fug 7 in the Bf109) had roughly the same range of about 30 miles to a ground station. This meant the German fighters were out of radio contact with their base once they got over the English Channel. Meanwhile, the British had radio relay stations along the English coast that kept Spitfires and Hurricanes in touch with their sector controllers. The British TR9D radio had the extra feature of "Pip-Squeak" which transmitted a signal that could be triangulated to tell British controllers exactly where their fighters were, to guide them to interception and help pilots who got lost above cloud or at night. The British saw radio as a vital part of the defence system, whereas the Germans had much less regard for its value. 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! The British had been on the verge of switching to a new Very High Frequency (VHF) radio system with much-increased range (150 miles) with better reception in 1940. This plan had to be delayed because of the demands of the Battle of Britain. However, once the Battle was over the new system was quickly put into place and operational in the South of England by the end of 1940. The Germans had to wait until the end of 1942 to get a similar VHF system for their fighters.
PRODUCTION AND COST
The Air Ministry initially ordered only 310 Spitfires from Supermarine. This was not enough to warrant investment in expensive new presses and tooling to simplify production and ultimately bring down costs. As it was, Supermarine struggled to complete the order on time because of the cramped factory space available to them. If the initial order had been for 1,000 or more aircraft then no doubt Supermarine would have set up a whole new factory and purchased new tooling and presses to build the Spitfire more cost-effectively and maybe altered the design to cut down the number of hand-finished parts. However, building a new factory and making the changes would have in turn delayed the production programme. There is no doubt that Spitfire airframes built in Southampton, or later at the dispersed sites in the south of England, took more man-hours to build than the airframe of a Bf109. It is not quite so clear cut if you add in the hours to build the engines, radios, guns and other ancillary equipment. The Spitfire airframe production line at Castle Bromwich, once it got going, was more efficient, benefitting from large presses and other tooling purchased from the USA, bringing aircraft produced there closer to the man-hours needed to build a Bf109 airframe.
Trying to compare the costs of the Spitfire and Bf109 is an impossible and ultimately irrelevant task. The economies of Britain, Germany and the USA operated on completely different levels. The cost of living and wages in Germany were much lower than in Britain and in turn, the cost of living and wages in Britain were in the order of half those in the USA. The cost of raw materials in the three countries also differed greatly. It is like trying to compare the cost of a modern-day motorcar made in the USA with one made in Vietnam or China. In the case of Nazi Germany, the matter is further complicated by the use of forced and slave labour. Comparing costs means trying to come up with meaningful exchange rates between the British Pound and German Reichsmark, which pundits inevitably do by converting them into US Dollars, ignoring the fact that the Pound was artificially pegged at a constant exchange rate to the Dollar throughout most of the war years, and so does not reflect a meaningful comparison. Some of the prices quoted for Spitfires in discussions on the subject are way off. The figure of £8,783 is often given for a Spitfire, but this was the price of only the first 50 Spitfires off the production line. By the beginning of 1940 Spitfires were being produced for only £4,725 each and by 1942 the Mk IX Spitfire airframe cost only £4,425. ⁸
AFTER THE BATTLE OF BRITAIN
When the Battle of Britain ended, the RAF was starting to receive Spitfire MkIIs with a slightly increased performance. This was countered on the German side by the increased availability of the Bf109E-4N, Bf109E-7 and then the Bf109F. The Bf109F outclassed the Spitfire Mk I and II in speed and ceiling but was then, in turn, countered in early 1941, by the Spitfire Mk V although in certain aspects the Bf109F retained a very slight edge. The arrival, in late 1941, of the Focke Wulf FW 190 gave the Germans an aircraft that could comprehensively out-perform the Spitfire V 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 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.
NOTES
¹ In the various sources I have consulted the maximum speeds of the Spitfire and Bf109 quoted vary from 346 to 365 mph (557 to 587 kph) for the Spitfire Mk I and from 345 to 357 mph (555 to 574 kph) 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. The timing of the RAFs use of 100 octane fuel is widely debated on the internet. Documents seem to show that the RAF's interest in using the fuel came a lot earlier than many writers suggest, with as many as three operational squadrons using it for trials as early as 1937. Likewise, mass conversions of front-line Spitfires and Hurricanes to use 100 octane fuel are documented in squadron log books from as early as March 1940.
² 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.
³ "Anti-g suits" were developed independently in both Canada and Australia. The Canadian "Franks" suit was used by some Royal Navy Seafire pilots from late 1942, while the Australian "Cotton" suit was used by Royal Australian Air Force Spitfires in the Far East from 1943. But the Royal Air Force never adopted an anti-g suit during WWII (neither did the Germans, who put all their efforts into the prone position means of withstanding g forces).
⁴ 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.
⁵ 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".
⁶ Interestingly, the US Army Air Corps (USAAC) sent a team to look at lessons that could be learned from the Battle of Britain. They already used a continuous flow of oxygen from high-pressure tanks, but they concluded that low-pressure tanks would be safer, having less risk of explosions or fires. So the USAAC switched to a new low-pressure system (the US Navy stuck to high-pressure oxygen tanks). This ended up being a big mistake, since USAAC aircraft had to carry twice the number of oxygen tanks, or much larger tanks (it also meant that USAAC aircraft supplied to Britain under lend-lease were incompatible with the British high-pressure oxygen equipment). So, halfway through the war (from 1943), the USAAC had to switch over again, back to a high-pressure system, this time one that incorporated a regulator system.
⁷ British fighter pilot Hugh Dundas wrote an article about the RAF's first use of the "Finger Four" formation for the London Evening Standard newspaper in July 1960. The article was reprinted in "The Battle of Britain Remembered" Issue 4, the magazine of the Battle of Britain Historical Society.
⁸ Spitfire costs are for the airframe only, the engine and armament were purchased under separate contracts.
Suggested further reading on the subject of Spitfire V Bf109
Survival of the Fittest. An article by David Baker in the October 2000 edition of Aeroplane magazine.
The Decisive Duel - Spitfire vs 109. A book by David Isby, paperback edition published in 2013 by Abacus publishing. ISBN 978-0-349-12365-3.
The Historic Aircraft Association website has short articles about what it is like to fly both the Spitfire and Bf109. The Spitfire article can be read at <this link>. The Bf109 article can be read at <this link>.
See also a wider bibliography on the Spitfire at <this link>.
The bulk of this essay was first published in 1992 as part of my book on a floppy disk "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, where new information has come to light. 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.
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