History of the Bf 109: E to F variants

The Emil: The most important variant of the classic fighter family available for the Luftwaffe in the first years of WW2, it was fundamental on the Luftwaffe´s efforts to establish and then hold air superiority over the Polish, Norwegian and Northern Europe battlefields between September 1939 and June 1940.

Bf 109E-0: Since the beginning of the Bf 109 program, it had been agreed that the inverted V Daimler Benz DB 600 engine would power this variant. The first aircraft with engine was the Bf 109V10, which first flew on July 1937 with the DB 600Aa, using a three-bladed metalic propeller of constant speed. A number of prototypes followed, together with the Bf 109D, until the arrival of the Bf 109s V14 and V15, which introduced the definitive DB 601 engine, rated at 1050hp on takeoff and built with a direct fuel injection system instead of the DB 600´s carburator. The direct injection fuel system allowed the pilot to perform negative-G maneuvers, without fearing the engine stopped. After the delivery of 10 Bf 109E-0s with a quarter of 7,92mm MG 17 machineguns, the Bf 109E-1 entered in service.

Bf 109E-1: It entered service in February of 1939 with the same engine but with the wing´s armament changed to 2x 20mm MG FF cannons with 60 bullets each and 2x 7,92mm MG17s with 1000 bullets each on the engine cowling. Initial deliveries were to Germany based units and, even though the Spanish Civil War was ending, to Jagdgruppe 88.
The Bf 109E-1/B was a fighter-bomber conversion developed in the spring of 1940, with a fuselage strongpoint to carry a 250kg bomb, though it only carried a bomb of 50kg due to range limitations.
A total of 1183 Bf 109E-1s were produced. Compared to its advesaries, the D.520 and Hurricane, the E-1 enjoyed of a better climb rate, stability as a weapons platform and direct fuel injection. On the Battle of Britain, its main problem ended up being its short range, which gave pilots only a few minutes over the battlefield before having to return to their airfield. After the Battle, the E-1 was superseded by following Emil variants and the F version.

Bf 109E-3: It was a development of the E-1, with the DB 601Aa rated at 1175hp on takeoff and the installation of an MG FF/M 20mm cannon between the engine cylinders, only if the machinegun ammunition was reduced. It had a revised canopy and, for the first time, armor for the pilot.

Bf 109E-4: Appearing for the first time at the end of 1939 and on the spring of 1940, it was an E-3 development with the MG FF/M cannons removed and replaced with fast firing MG FF cannons of 20mm with 60 shots each on the leading edge of the wings and 2x 7,92mm MG 17s with 1000 shots each on the engine cowling, syncronized to fire through the propeller arc. It was also equipped with a DB 601Aa engine in inverted V rated at 1175hp on takeoff and 1000hp at 3700m, an internal fuel capacity of 400 litres, wingspan of 9,87m, length of 8,64m, height of 2,50m, an empty weight of 2125kg, maximum takeoff weight of 2665kg, a maximum leveled speed of 560km/h at 4438m declining to 467km/h at sea level, a maximum cruising speed of 483km/h at 4000m, economic cruising speed of 325km/h at 1000m, maximum range of 660km, climb rate at sea level of 1000 meters/minute, a climbing time to 6000m of 7 minutes and 45 seconds and a service ceiling of 10500m.

Bf 109E-4/B: Fighter-bomber version developed in the spring of 1940, with a strong point under the fuselage to carry one 250kg bomb or 4x50kg bombs.

Bf 109E-4/Trop: Same as the E-4, but with a sand filter for desert operations.

Bf 109E-5: Reconnaissance version derived from the E-4, with the wing cannons removed and with an Rb 50/30 camera in the fuselage right behind the cockpit.

Bf 109E-6: Development of the E-5 with a DB 601N in inverted V rated at 1200hp at takeoff.

Bf 109E-7: Variant of the E-4/N with reinforced points under the fuselage revised to carry one 250kg bomb or one 300 litre fuel tank. It had the same armament of the E-4.

Bf 109E-7/Trop: E-7 variant with a sand filter for desert operations. It had the same armament of the E-4.

Bf 109E-8: E-7 development with a DB 601E rated at 1350hp at takeoff.

Bf 109E-9: Reconnaissance version of the E-8 without the wing cannons and an installation which could have an Rb 50/30 camera or two 32/7 cameras. The last units were delivered at the beginnings of 1942, ending the Bf 109E´s production after 4000 units.

The Friederich: The cenit of the Bf 109 regarding aerodinamic and maneuvering qualities, but these refinements were achieved by sacrificing weaponry, which was too light to be considered effective. Thus, the Bf 109F production was cancelled after the delivery of 2200 units. Messerschmitt´s design team had decided at the beginnings of 1940 (when the Bf 109E was relatively new), that the British and French would try to challenge German´s air superiority with improved versions of the Spitfire, Bloch MB 151/152 and Dewoitine D.520. France lost the war in June 1940, before it could deploy an improved fighter, but Britain answered to the Bf 109E with the Spitfire Mk.V with the Rolls Royce 45 engine and a two-staged supercharger. The Luftwaffe was, nevertheless, ready for this, and began to operate the Bf 109F since March of 1941, initially with the Fighter Wings 2 and 26 (JG 2 and JG 26) from bases south of the Channel.
The Bf 109F had been aerodinamically refined to take advantage of the latest version of the DB 601, the DB 601E, rated at 1350hp at takeoff. Research had shown that most of the drag on the Bf 109E came from the underwing radiators designed to cool the engine, and a decision was made to make them smaller and extend them more behind the wing, with a bypass system that collected turbulent air on the inferior part of the wings immediately in front of the radiators, sent it through the upper part of the radiator and expelled it through a conduct located in the flaps closest to the fuselage, which were divided on top and bottom, acting together with the normal flaps but controlled by a thermostat which opened them when the coolant´s temperature raised, serving as a lip for the radiator. Other changes on the wings, which had been reduced in length, were the reduction of the slats and the ailerons (later increased to keep their chord)
Nevertheless, changes didn´t end there. The cowling was enlarged to give it a more symmetrical aspect, which lines were continued by the propeller´s nosecone, which included one of smaller diameter, the supercharger air entrance was moved further on the cowling´s left side. The rudder was made smaller, the horizontal stabilizers were modified as cantilever units withouth the Bf 109E´s struts. The tailwheel was made semi-retractable and the landing gear was inclined forward.
The result of all of this was the reduction of drag on the aircraft and, combined with the DB 601E, it offered better characteristics on every flight envelope.

Bf 109V21: First Bf 109F prototype. It retained the DB 601Aa engine of the Bf 109E but with all of the aerodynamical improvements and a reduction of the wingpspan of 0,60m and the posterior addition of the DB 601E. Further tests showed that said reduction negatively impacted on the Bf 109F performance.

Bf 109V22: Second prototype. No data.

Bf 109V23: Third prototype. It followed the steps of the V21 but with the addition of semi-eliptic wingtips that restored everything except 0,20m of the original wingspan, improving its maneuverability.

Bf 109V24: The fourth prototype introduced an improved supercharger intake and a deeper oil cooler chin in the front of the fuselage. From the beginning it had been decided to concentrate the Bf 109F’s armament on the nose, so the 2x 7,92 MG 17s with 500 bullets each were left untouched, but the wingroots MG FF 20mm cannons were replaced by a single 15mm MG 151/15 with 150 bullets shooting through the nose cone. The loss of the wingroot weapons gave the aircraft a better maneuverability, and the reduction in firepower was compensated by the better firing rate and fiability of the MG 151 and, compared to the MG FF, could carry more bullets because it was belt-fed instead of being fed by a drum.

Bf 109F-0: While the pre-production Bf 109F-0s were being built on the autumn of 1940, neither the DB 601E nor the MG 151 were ready, so the aircraft were equipped with the DB 601N rated at 1200hp for takeoff and 1270hp at 5000m, 2x 7,92mm MG 17 machineguns and an MG FF/M cannon of 20mm on the nose. Normal takeoff weight was of 2610kg. Testing on the Bf 109F-0 gave mixed results: the pilots were very enthusiastic regarding the increased maneuverability but were unhappy regarding the loss of firepower. The advantages over the Bf 109E were evident though, and the mass production was authorized.

Bf 109F-1: It was differenf from the F-0 in that the supercharger intake was circular. Aircraft were available at the end of 1940, but its introduction was delayed due to the loss of several machines thanks to the eliminartion of the stabilizers struts: the lack or rigidity on the tail combined with the vibrations of the engine at certain RPMs generated structural failures. The problem was solved with the addition of external reinforcement plates and the Bf 109F-1 entered service in February 1941.

Bf 109F-2: This was a development of the F-1 with the 15mm MG 151 cannon belt-fed with 150 shots against the 20mm MG FF/M drum-fed with 200 shots. Because it was the first definitive model of the “Friedrich”, it was produced in several subvariants, just like the Bf 109E, with extra thrust systems, tropicalised equipment. Other details of the Bf 109F-2 were the DB 601N in inverted V, rated at 1200hp for takeoff and 1270hp at 5000m, with an internal fuel load of 400 litres, external fuel load of 300 litres, wingspan of 9,92m, length of 8,94m height of 2,60m, empty weight of 2353kg, normal takeoff weight of 2800kg and maximum takeoff weight of 3066kg. Maximum leveled speed was of 600km/h at 6000m declining to 517km/h at sea level, a cruising speed of 560km/h at 5000m, an economical cruising speed of 354km/h at sea level, a maximum range of 880km with the external fuel tank, a climb rate of 1177 meters/minute with 5 minutes and 12 seconds to reach 5000m. Service ceiling: 11000m.

Bf 109F-3: Development of the F-2 but with the DB 601E. It was rated at 1350hp on takeoff and 1300hp at 5500m.

Bf 109F-4: Produced in parallel with the F-3, this variant introduced the 20mm MG 151/20 cannon which fired through the propeller´s cone. This required the reduction of the ammo from 200 to 150 bullets. This model had several improvements done, like self-sealing fuel tanks, better protection for the pilot in the shape of a more armored front canopy and reinforcements to the sides for protection agains lateral attacks, a Revi C/12D reflective aim and a switch which allowed to fire the guns independently or together.
From this point onwards, differences started to appear regarding the armament: some aces led by Werner Mölders, favoured the current armament of on 20mm cannon and two 7,92mm machineguns while others, led by Adolf Galland, wanted more weapons so as the average pilot could score a kill. A solution to these differencs was the inclusion of fiel modificatio of equipments, which had several armament combos.

Bf 109F-5: Tactical reconnaissance version of the F-4 with the engine cannon removed and one vertical camera installed in the rear part of the fuselage and with an external fuel tank of 300 litres.

Bf 109F-6: A more tactical variant of the F-5. All the armament was removed and an special area was added for an Rb 20/30, Rb 50/30 or Rb 75/30 camera. A small number of F-5s and F-6s were produced and, for the end of 1941, the F series had been replaced by the Gustav.
There were two special variants: the F-6/U specially produced for Adolf Galland. It was basically an F-2 with 2x 20mm MG FF cannons and one that replaced the 2x 7,92mm machineguns in the nose for two heavy machineguns MG 131 of 13mm.

Bf 109E-0:

Bf 109E-1:

Bf 109E-3:
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Bf 109E-4:
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Bf 109E-4/Trop:
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Bf 109E-7:
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Bf 109E-7/Trop (Iraqi Air Force):

Bf 109V23:
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Bf 109V24:
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Bf 109F-1:
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Bf 109F-2:

Bf 109F-4:

Bf 109F-4/Trop:
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Next: Variants G to K.

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