Messerschmitt Bf 109

The Messerschmitt Bf 109 was a World War II fighter aircraft designed by Willy Messerschmitt in the early 1930s. It was one of the first true modern fighters of the era, including such features as an all-metal monocoque construction, a closed canopy, and retractable landing gear.

The Bf 109 was the standard fighter of the Luftwaffe for the duration of WWII, although it began to be partially replaced by the Focke-Wulf Fw 190 from 1942. The Bf 109 scored more aircraft kills in World War Two than any other aircraft. At various times it served as an air superiority fighter, an escort fighter, an interceptor, a ground-attack aircraft and a reconnaissance aircraft. The Bf 109 was produced in greater quantities than any other fighter aircraft in history, with over 31,000 units built. Although the Bf 109 had weaknesses, including a short range of early variants around 400 miles (640 km) on internal fuel as drop tanks were not standardized until the E-7 model appearing in mid-1940, and a sometimes difficult to handle narrow, outward-retracting undercarriage, it stayed competitive with Allied fighter aircraft until the end of the war.

The Bf 109 was flown by the three top scoring fighter aces of World War II : Erich Hartmann, the top scoring fighter ace of all time with 352 victories, Gerhard Barkhorn with 301 victories, and Günther Rall with 275 victories. All of them flew with the Jagdgeschwader 52, chiefly on the Eastern front, a unit exclusively flying the Bf 109 models and being credited with over 10 000 victories itself. Hartmann refused to fly any other airplane in combat throughout the war. Hans-Joachim Marseille, "The Star of Africa" also flew the Bf 109, and achieved all of his 158 victories on the Western Front, chiefly against Allied pilots in North Africa, including 17 aircraft shot down in a single day.

Designation

Bf 109 was the initial Reichsluftfahrtministerium (the German Air Ministry) designation, since the design was sent in by the Bayerische Flugzeugwerke company, and used exclusively in all official German documents dealing with this aircraft family. After the company was renamed to Messerschmitt AG after July 1938, when Erhard Milch finally allowed Willy Messerschmitt to acquire the company, from that onwards all Messerschmitt aircraft were to carry the "Me" designation - at least in theory, as wartime documents from Messerschmitt AG, the RLM and others kept using both designations, sometimes even on the same page! Me 109 is known to have been the name used in print by the Luftwaffe propaganda publications as well as by the Messerschmitt company itself after July 1938, and the Luftwaffe personnel, who pronounced it may hundert-neun. The Me 109 (pronounced "emm ee one-oh-nine") designation was usually used in the Anglo-Saxon world. However, in both wartime and contemporary literature, both the "Bf" and "Me" prefixes are used, and both are considered valid and accurate — although some debate still occurs over this issue from time to time.

Contest history

During 1933 the Technisches Amt (or T-Amt, the technical department of the RLM) concluded a series of research projects into the future of air combat. The result of the studies was four broad outlines for future aircraft:

• Rüstungsflugzeug I for a multi-place medium bomber
• Rüstungsflugzeug II for a tactical bomber
• Rüstungsflugzeug III for a two-seat heavy fighter
• Rüstungsflugzeug IV for a single-seat fighter

The Rüstungsflugzeug IV was intended to be an all-metal monoplane single seat fighter aircraft, or interceptor actually, replacing the Arado Ar 64 and Heinkel He 60 biplanes then in service. While it was intended the R-IV aircraft would best all others then flying, the requirements were nevertheless not terribly hard to meet.

The plane needed to have a top speed of 400 km/h at 6,000 m (250 mph at 19,500 ft) which it could maintain for 20 minutes, while staying in the air for a total of 90 minutes. It was to be powered by the new Junkers Jumo 210 engine of about 700 hp (522 kW). It also needed to be armed with at least three 7.9 mm machine guns with 1,000 rounds each, or one 20 mm cannon with 200 rounds. One other interesting specification was that the plane needed to keep wing loading below 100 kg/m², which is a way of defining the plane's ability to turn and climb. The priorities for the plane were level speed, climb speed, and then maneuverability (in that order).

In fact the R-IV specifications were not actually thought up inside the T-Amt at all. In early 1933 both Heinkel and Arado had sent in privately-funded designs for a monoplane fighter, and the T-Amt simply collected the best features from both and sent them back out again, adding Focke-Wulf to the tender. In May 1934 the R-IV request was sent out and made official. Each was asked to deliver three prototypes to be delivered for head-to-head testing in late 1934.

Willy Messerschmitt was originally not invited to participate in the competition. This was mainly due to personal animosity between Messerschmitt and RLM director Erhard Milch (Hans Hackman, a close friend of Milch, was killed testing the prototype Messerschmitt M20 light transport plane), after the M20 proved a disaster in Lufthansa use. Nevertheless Messerschmitt was on very good terms with many high ranking Luftwaffe officers based on the success of the Messerschmitt Bf 108 Taifun sports plane. After a delay of several months, Bayerische Flugzeugwerke (Bavarian Aircraft Manufacturers, or BFW) for which Messerschmitt was head designer, was invited to take part in early 1935, although Milch let it be known that they would never win the contract.

Design features

File:Bf 109E-4.jpg

A German Bf 109-E4 ahead of a Romanian Bf 109-E4.

Messerschmitt had already designed much of the Bf 109 by this point. Like the Bf 108, the new design was based on Messerschmitt's "lightweight construction", which essentially aimed to reduce the total number of strong parts in the aircraft as much as possible. One of the more notable examples of this was the mounting of all structural points to a strong firewall at the front of the cockpit, including the wing spars, engine mounts and landing gear. In more conventional designs these would be mounted to different points on the aircraft, with a framework distributing the load among them.

Another notable advantage of this design was that, since the landing gear was attached to the fuselage itself, it was possible to completely remove the wings of the aircraft for major servicing, if necessary, leaving the fuselage intact sitting on the landing gear. However, this had one major drawback - such a landing gear arrangement ensured a very narrow track (the distance between the main tyres) which thus made the plane very unstable in terms of balance while on the ground. In fact, the Bf 109 was notoriously difficult to take off and land, and many planes simply veered off or tipped over to one side during a seemingly perfect run. To make things worse, the landing gear struts were comparatively long. This left the nose pointing up at quite a steep angle with respect to the ground, making forward visibility during taxiing virtually zero. These landing gear-related problems plagued the Bf 109 throughout its life, and accounted for a notable proportion of losses: 5% of all Bf 109s produced were destroyed or written-off in landing accidents.

Reflecting Willy Messerschmitt's belief in low-weight, low-drag simple monoplanes the armaments were placed in the main body of the plane; two machine guns were mounted above the engine and a third could be fired through the airscrew hub, with the engine buffering the recoil. Fitting with Willy's ethos, this kept his gun-free wings very thin and lightweight. When it was discovered that the RAF was producing eight-gun monoplanes it became clear that the Bf 109 would have to carry more guns and a new wing was designed holding a machinegun, later a 20 mm MG FF cannon.

In 1938 the 'Emil' (see below) went into production, but to improve on the performance allowed by the rather small 600 to 700 hp Jumo engine the larger Daimler Benz DB 601A engine was used, yielding an extra 300 hp at the cost of an additional 400 lb.

Another aspect of this construction technique was the use of a single box-spar in the wing, mounted near the leading edge. Most planes of the era used two spars, near the front and rear, but the box was much stiffer torsionally, and eliminated the need for the rear spar.

Another major difference was the much higher wing loading than the other designs. While the R-IV contract called for a wing loading of less than 100 kg/m², Messerschmitt felt that this was unreasonable; with the engines available to them, the fighter would end up slower than the bombers it was tasked with catching.

A wing generates two forms of drag, parasitic drag due to its form, and induced drag which is a side effect of generating lift. The former dominates at high speeds, when the airflow hitting the wing causes drag that rises with the square of the aircraft's speed. The latter dominates at lower speeds, where the lack of airflow requires the wing to be angled into the airflow at a higher angle of attack. Since the fighter was being designed primarily for high speed flight, a smaller wing would be optimized for high speed use.

The downside of such a trade-off is that low speed flight would suffer, the smaller wing would require more airflow to generate enough lift to stay flying. In order to address this, the Bf 109 included advanced high-lift devices on the wings, including automatically opening slats on the leading edge, and fairly large camber-changing flaps on the trailing edge. When deployed, these devices effectively increase the coefficient of lift, making it better at low speeds and high angles of attack.

Another drawback of the high wing-loading is that the plane would require more energy to maneuver. Given the limited amount of power available, this effectively meant that the Bf 109 would not be able to turn as tightly as other designs with larger wings. The high lift devices would offset this to some degree, but they also increased drag and so slowed the plane further. Given that maneuverability was last on the RLM's wish-list, Messerschmitt was certain the benefits outweighed the drawbacks.

Prototypes

The first prototype (Versuchsflugzeug 1 or V1) was completed by May 1935, but the German engines were not yet ready. In order to get the designs into the air, the RLM acquired four Rolls-Royce Kestrel VI engines by trading Rolls-Royce a Heinkel He 70 Blitz to test their engines on. Messerschmitt received two of these engines, and started work on adapting V1 to mount it. This work was completed in August, and V1 took flight tests in September 1935. It was then sent to the Luftwaffe Test Center at Rechlin to take part in the contest.

By the late summer the Jumo engines were starting to become available, and V2 was completed with the Jumo 210A of 610 hp (448 kW) in October 1935. V3 followed, being the first to actually mount guns, but another 210 was not available and it ended up delaying the flight of V3 until May 1936. Like V1, V2 and V3 were sent to Rechlin after acceptance tests at the factory.

The flight data of these three planes were very nearly identical. The maximum airspeed was about 470 km/h at 4000 m altitude, and the service ceiling was about 8,300 m.

The contest

After Luftwaffe acceptance trials were completed at Rechlin, the planes were moved to Travemünde for the head-to-head portion of the contest. The Heinkel design arrived first, in early February 1936, and the rest of the V1s had all arrived by the beginning of March.

Because most of the fighter pilots of the Luftwaffe were used to good-natured biplanes with open cockpits, light g-forces and easy handling, they were very critical about the Bf 109 at first. However it was soon a front-runner in the contest, as the Arado and Focke-Wulf entries proved to be hopelessly outdated. Perhaps this isn't surprising, considering that those entries had actually been designed two years earlier, and given the rate of change in aircraft design at the time, they really had little chance against the much more modern 109.

The only serious competition to the 109 was the Heinkel entry. Based on a scaled down Blitz, the He 112 proved to be similar but different. Positive aspects of the He 112 included the wide track and robustness of the landing gear, considerably better visibility from the cockpit, and a lower wing loading that led to easier landings and better maneuverability. But the Bf 109 was 30 km/h faster than the He 112 in level flight, and also was superior in climbing and diving. Still, the He 112 was the favorite of the Luftwaffe leaders.

Orders for a further ten examples of both types were placed, and they started trickling in over the next few months. However by this point the Jumo-powered examples of both designs had arrived for testing, and the 109's better streamlining and lower drag meant that it was considerably faster given the lower-power engine.

Even before the pre-production models arrived the contest was basically over. In March the RLM received news that the Spitfire had been ordered into production, and a form of mass panic broke out. On March 12 they released a document that basically contained the outcome of the contest, Bf 109 Priority Procurement. Nothing occurred over the summer to change their minds, and the RLM instructed Heinkel to re-design the He 112 radically, while ordering the Bf 109 into production.

Models

Bf 109A/B/C

The planned Bf 109A "Anton" series was canceled before production begun, because of its weak armament (it was planned to have only two nose-mounted machine guns). Instead of this, the Bf 109 V4 was constructed, carrying a third MG 17, mounted under the engine between the cylinders, firing through the propeller shaft. In the following three prototype planes (V5, V6, V7), the new Jumo 210B engine was installed. They also were armed with three machine guns and were identical to the Bf 109B-0 pre-production series.

The first Bf 109 model that went in serial production, the B-1 "Bruno", was fitted with the more powerful Jumo 210D engine.

When the new Jumo 210E engine (rated at 670 hp (493 kW)) was developed, it was fitted to the cell of the Bf 109B, resulting in the Bf 109B-2. Both the B-1 and B-2 versions saw combat with the Condor Legion during the Spanish Civil War, in the process demonstrating that the armament was still inadequate. Thus the Bf 109 V8 was constructed to test the fitting of two more machine guns in the wings. In the following V9 prototype both wing guns were replaced by 20 mm MG FF cannons.

The short-lived Bf 109C series comprised the C-0 "Caesar" pre-production series, carrying four MG 17 machine guns; the identical C-1; and the C-2, which was armed with an additional machine gun in the nose, making a total of five MG 17 machine guns. The C-3 was tested with one 20 mm MG FF cannon in each wing, but only one prototype was ever produced.

The next model, the V10 prototype, was identical to the V8, except for its Jumo 210Ga engine (later models carried a Daimler-Benz DB600A). The V10, V11, V12 and V13 prototypes were built using Bf 109B airframes, and tested the DB600A engine with the hope of increasing the performance of the aircraft. However the DB600A was found to be unreliable, and as the improved DB601A was to soon become available the DB600A was dropped.

Bf 109D "Dora"

Developed from the V10 and V13 prototypes, the Dora was the standard version of the Bf 109 in service with the Luftwaffe during the period just before World War Two. Despite this, the type saw only limited service during the war, as all of the 235 Doras still in service at the beginning of the Polish campaign were rapidly taken out of service and replaced by the Bf 109E, except in some Nachtjäger (night fighter) units, where some examples were used into early 1940. Variants included D-0 and D-1 Models, both with a Junkers Jumo 210 engine and armed with two wing-mounted and two nose-mounted 7.92 mm MG 17 machine guns. The D-2 was armed with two MG 17 in the wings, and the D-3 with two 20 mm MG FF cannon in the wings.

Bf 109E "Emil"

Bf 109E

To test the new DB601A engine, with its 1,100 hp (808 kW), two more prototypes, the V14 and V15, were built, that differed in their armament. While the V14 was armed with the two MG 17 above the engine and one 20 mm MG FF cannon in each wing, the V15 got the two MG 17's above the engine and a MG FF/M firing through the propeller axis. After test fights the V14 was considered more promising and a pre-production batch of 10 E-0 was ordered.

The production version E-1 kept the two 7.92 mm MG 17's above the engine and had two MG 17s in the wings. Later many were modified to the E-3 armament standard. The E-1B was a small batch of E-1's produced to be the first operational use of a Bf 109 as fighter bomber. They were fited with either a ETC 250 bomb rack, carrying one 250kb bomb or two ETC 50 bomb racks, carrying a 50kg bomb under each wing. The E-2 was not built for unknown reasons.

To improve the performance of the Bf 109E, the last two real prototype planes were constructed, the V16 and V17. They got some structural improvements and stronger armament. These prototypes were the basis of the Bf 109E-3 version. They were armed with the two MG 17's above the engine and one MG FF cannon in each wing . The E-3 also received heavier armor than the E-1 and optional an improved DB601Aa with 1,100 and 1,175 hp respectively. The E-3a was an export version without equipment classified as secret.

The E-3 was replaced by the E-4 (with many airframes being upgraded to E-4 standards starting at beginning of the Battle of Britain) which was different in some small details, most notably by the modified MG-FF/M wing cannon and by improved head armor for the pilot. The MG FF/M fired a new and improved type of explosive shell, called Minengeschoß (or 'mine-shell') which was made by drawn steel (the same way brass cartridges are made) instead of being cast as was the usual practice. This resulted in a shell with a thin but strong wall, which hence had a larger cavity in which to pack a much larger explosive charge than was otherwise possible. The new shell required modifications to the MG FF's mechanism due to the different recoil characteristics, hence the MG FF/M.

The canopy was also revised to an easier-to-produce, "squared-off" design, and stayed fairly unchanged until the introduction of the 'Erla' canopy on the G-6 in the autoumn of 1943. The E-4 would be the base for all further Bf 109 E developments. Some E-4 and later models got a further improved 1,175 hp (875 kW) DB601N high-altitude engine resulting in a slightly changed model number like E-4/N, first appearing in July 1940. The DB601N was the standard engine used in most E-6 and onwards production versions.

The E-1 and E-4 saw the most heavy action during the Battle of Britain - most of the E-3s were already converted to E-4 standard. The fuel-injected DB601 engine of the Bf 109 proved most useful against the British Supermarine Spitfire and Hawker Hurricane fighters, as the British fighters used gravity carburetor engines, which would cut out under negative g forces whereas the DB601 did not. The Bf 109s thus had the initial advantage in dives, either during attack or to escape it was able to get out of gun range. The Spitfire proved a formidable opponent, being approximiately as fast and is claimed somewhat more maneuverable in turns at medium to high speeds than the Bf 109 (the latter due to the Bf 109's high wing loading). On the question of comparative turning circles in combat, Spitfires and Hurricanes benefited from their lower wing loading compared with the Bf109; 22 to 24 pounds per square foot on the RAF machines against 32 pounds per square foot for the Bf 109. Royal Aircraft Establishment tests with a captured Bf 109 showed the Spitfire's turning circle — without height loss — was 696 feet (212 m) in radius (the Hurricane's would be slightly tighter) while the 109's was 885 feet (270 m) radius according to British calculations using assumed values as basis. According to the German manuals however, the smallest turning circle was 170 m, and fighter pilots on both sides claim they would out-turn their opponents in combat. In roll rates the Bf 109 enjoyed advantage at dogfight speeds, though at high speeds the manouveribilty of all three fighters, especially the Spitfire was severly limited in this regarg. The Bf 109 enjoyed good handling near stalling speeds as it was particularly forgiving then. Firepower between the two main antagonists was comparable, with the Spitfire's eight .303 inch machine guns versus the Bf 109's two 7.92 mm MG17 machine guns and two 20 mm MG FF cannon. However, the MG FF occasionally jammed and had a small (60-round) ammunition capacity. To be fair, when the Spitfires were later upgraded to two 20 mm Hispano-Suiza cannon, the British initially had serious jamming problems of their own with the new weapon. RAF pilots who tested captured Bf 109s liked the engine and throttle response but criticised the high speed handling characteristics, poorer turning circle, greater force required on the control column at speed and the thick framing of the cockpit glazing which they felt created blindspots in the pilot's field of vision.

It should also be noted that throughout its life the Bf 109 suffered from ground accidents due to "swing" on takeoff and landings. It has been suggested that 5% of all 109s were lost this way, or even one third; the Luftwaffe's loss records on the other hand show that approximately 1% of the Bf 109s had suffered landing incidents or accidents at the beginning of its career, a figure comparable to the other monoplane fighters introduced at the time. This feature was, however, more of a problem with rookie pilots, especially during later stages of the war. The interesting fact is that Spitfire had a similar , narrow landing gear arrangement, but there hasn't been widespread talk about operational losses, and it has been speculated that the swing was due to the toe-in of the main landing gear wheels. Most Finnish pilots report that the swing was easy to control,but some of the less experienced pilots lost planes on startup.

Bf 109E variants and sub-variants

• E-0 (Pre-Production Aircraft with four MG 17 7.92 mm machine guns)
• E-1 (Similar to E-0)
  • E-1/B (Fighter-bomber version of E-1, usually with DB 601Aa)
• E-2 (Not built)
• E-3 (Armament; 2x MG 17's above the engine and a MG FF in each wing. Modified canopy)
• E-4 (Armor and structural improvements, change of MG FF cannons to MG FF/M. Return to 'normal' canopy)
  • E-4/B (Fighter-bomber version of E-4, one 250 kg bomb, usually with DB 601Aa)
  • E-4/Trop (Version of E-4 modified to serve in tropical regions)
  • E-4/N (E-4 with DB601N engine)
  • E-4/BN (Fighter-bomber version of E-4/N, one 250 kg bomb)
• E-5 (Recon version of E-3, camera equipment, two MG 17)
• E-6 (Recon version of E-4/N, camera equipment, two MG 17)
• E-7 (Similar to E-4 but with optional external fuel tank)
  • E-7/N (Similar to E-4/N but with optional external fuel tank)
  • E-7/NZ (also E-7/Z) E-7/N with additional GM-1 injection system
  • E-7/U2 (Ground attack variant of E-7)
• E-8 (long range version of E-1 using drop tank installation of E-7, four MG 17)
• E-9 (Recon version of E-7/N, drop tank, camera equipment, two MG 17)

Bf 109F "Friedrich"

After February 1940 an improved engine, the Daimler-Benz DB601E, was developed for use with the Bf 109. The engineers at the Messerschmitt facilities took a Bf 109E-1 airframe and installed this new powerplant, Luftwaffe marking VK+AB, it's production number was 5604. The fuselage was cleaned up and the engine cowling modified to provide improved aerodynamics. The relationship to the standard E-1 version was obvious, because the trapeziform wings were taken from the E-1, although this was later changed in the production models of the F version. This adaptation became the prototype for the Bf 109F series. As the DB601E was not yet available in numbers the pre-production F-0 (the only F variant to have a rectangular supercharger intake) and the first production series F-1/F-2 received the 1,175 hp (875 kW) DB601N engine. The 1,350 hp (1,005 kW) DB601E was first used in the F-3 model together with an enlarged propeller with improved performance.

Externally the Bf 109F differed from the E-series, resulting from many aerodynamic improvements. The stabilizer struts were removed, the cowling was shaped to be more streamlined, the big underwing radiators were much smaller, the opening for the supercharger was improved to a round one from F-1 variants on, the flaps were completely changed, the wingspan was increased to 9.92 m, and the wing tips now were formed elliptically, which supposedly caused some confusions with the Spitfire. The redesigned wing made the internal mounting of guns impractical, so armament was revised. The armament of the Bf 109F consisted of the two MG 17 above the engine plus a cannon firing through the propeller hub: The early F versions were equipped with the MG FF/M cannon, the F-2 got the 15 mm MG 151, and from F-4 on the 20 mm MG 151/20 was used. Several aces, particularly Oberst Adolf Galland, criticised the light armament as inadequate for the average pilot. Major Walter Oesau even refused to fly an F as long as 'Emil's were still available. Only after a lack of spare parts, did he accept an F. Later on an attachment of underwing 20 mm cannons addressed the issue of fire-power but at a price to performance. Werner Mölders on the other hand was very much pleased and saw the single centerline gun as an improvment. It is possible that the criticism of the Bf 109F's armament is based on the early F-2 version with the 15 mm MG 151/15 cannon, which was later replaced by the 20 mm version of the same weapon and was seen highly effective by aces like Günther Rall.

The first Bf 109F planes were not well tested, and so some planes crashed or nearly crashed, due to vibrations which caused either the wing surface to curve or break, or caused the stabilizer to break away. In one such accident, the commander of JG 2 "Richthofen", Wilhelm Balthasar lost his life when he was attacked by a Spitfire during a test flight. Making an evasive maneuver, his wings broke away and Balthasar was killed when his plane hit the ground. When the wreck was investigated, not a single bullet hole was found. However, the teething problems were subsequently solved, and pilots generally agreed that the F series were the best-handling of all the Bf 109 series.

Bf 109F variants and sub-variants

• F-0 (Pre-Production Aircraft built from E series airframes, Adolf Galland was one of the few to fly one operationally)
• F-1 (Armed with one MG FF/M 20 mm cannon and two MG 17 7.92 mm machine guns)
• F-2 (Armed with one MG 151 15 mm cannon and two MG 17)
  • F-2/trop tropicalized version
• F-3 (F-2 with 601E engine, small production and most upgraded to F-4 standard)
• F-4 (Armed with one MG 151/20 20 mm cannon and two MG 17)
  • F-4 R1 (Two 20 mm cannon in underwing packs, special purpose variant, only in small numbers)
  • F-4/Z additional GM-1 injection system
• F-5 (Recon version of F-4, only two MG 17)
• F-6 (Reconversion of F-4, improved camera equipment)

Bf 109G "Gustav"

Bf 109G-6 on display in the Polish Aviation Museum in Cracow.

When the 1,475 hp Daimler-Benz DB 605 engine was available, a new Bf 109 series, the G-series, was developed. The early versions of the Bf 109G looked quite similar to the Bf 109F-4, and at first carried the same armament. The G-series saw the appearance of the notorious bulges in the cowling (caused by the DB605 (additional cooling) and by replacing the 7.92 mm MG 17 with 13 mm MG 131 machine guns (G-5 onwards)) and on the wings (due to larger main gear wheels, G-4 onwards), leading to the Bf 109G's nickname "The Bulge" (German: "Die Beule"). The DB605 suffered several reliability problems during the first year of operation forcing Luftwaffe units to lower max power to about 1,310 hp (975 kW) until October 1943. Other changes included an enlarged supercharger for the DB605 and an enlarged vertical stabilizer (G-5 onwards). All this was part of the continuous effort to increase the speed of the Bf 109, especially as the Allies deployed better and faster fighters like the P-51D and the later Spitfires. It has been suggested that the added weight of the new engines and heavier armaments badly affected the handling characteristics of the Bf 109, especially since it already had a high wing loading. While technically the statment is true, it is somewhat unfair as analysis show only a modest increase in weight as a result of development, fairly compareable to the development trend with Western Allied fighters.

With the Gustav, a number of special versions were introduced to cope with special mission profiles. Here, long range fighter-reconaissance and high-altitude interceptors can be mentioned. The former were capable carrying two 300 liter drop-tanks, one under each wing, the latter received pressurized cockpits for pilot comfort and GM-1 nitrous oxide 'boost' for high altitudes. The latter system was capable of increasing engine output for limited periods by 300 horsepower above rated altitude and high altitude performance above of that of any Allied fighter in service in 1942-43.

The G-6 model, the most produced Bf 109 version, had heavier armament. The G-6/U4 variant with Rüstsatz R6 was armed with two 13 mm MG 131 above the engine, a 30 mm MK 108 cannon shooting through the propeller hub and one 20 mm MG 151/20 in a 'pod' under each wing. The G-6 was very often fitted with assembly sets, used to carry bombs or a drop tank, for use as nightfighter, or to increase fire power by adding rockets or extra guns. During 1943, a number of improvements were gradually introduced for the type's benefit : armoured glass head-rest ('Galland Panzer') (early 1943), and the introduction of the clear-view 'Erla Haube' canopy (autumn 1943) improved visibility -especially to the rear, and a taller tail unit improved stability at high speeds. The introduction of the WGr. 21cm under-wing mortar/rockets and the 30 mm MK 108 cannon increased firepower. Certain production batches of the Gustav were fitted with aileron Flettner tabs to decrease stick forces at high speeds. Advanced radio/navigational equipment was also introduced.

Subsequent Bf 109G versions were basically modified versions of the G-6. Early in 1944, new engines with larger superchargers for improved high-altitude performance (DB 605AS), or with MW-50 methanol-water injection for improved low/medium altitude performance (DB 605AM), or these two features combined (DB 605ASM) were introduced into Bf 109G-6.

The G-14, appearing in mid-1944 was basically a late-war Bf 109G-6 with the aforementioned improvements standardized, and methanol injection increasing output to 1800 HP being a standard fitting. High-altitude models received an /AS suffix (G-6/AS, G-14/AS). There was increasing tendency to use wood on some less vital parts (e.g. the tailfin, pilot seat or instrument panel) - not because of the shortage of strategic materials like aluminium as often suggested, but as it allowed freeing up metalworking capacity by involving of the woodworking industry of more parts.

The G-10 was not a uniform type, but consisted of all kinds of Bf 109Gs being transformed to Bf 109G-10 specifications as well as completely new aircraft builds, with the aim being an interim solution produced with mininal distruption of production lines using the Gustav airframe, but equipped partly to the Bf 109K-4 - most notably sharing the DB 605 D engine as well as the new 2000 Watt generator. Despite what the designation would suggest, it appeared in service after the G-14 and somewhat the K-4 in November 1944. The most recognizable change was the use of the "ERLA-Haube" canopy, sometimes referred to (incorrectly) as the 'Galland' hood. This canopy improved the pilot's view by reducing the number of support struts, which was often criticized before. As with many 'interim solutions' of the war, it was produced in very substantial numbers, with some 2600 G-10s produced until the war's end. The Bf 109G-10, AS-engined G-6s and G-14s as well as the K-4 saw a refinement of the bulges covering the breeches of the cowl mounted MG 131, these taking on a more elongated and streamlined form.

A similar varying product was the Bf 109G-12. This was a two-seat trainer version of the Bf 109 and was rarely armed.

Bf 109G variants and sub-variants Variants could be equipped with a "Rüstsatz" add-on kit (field modification) or a "Umrüst-bausatz", or Umbau, conversion kit (factory conversion). In either case, the modified aircraft were identified with either an /R or /U suffix, eg. Bf 109G-10/U4.

Common Umrüst-Bausatz [Umbau] numbers

• U1 Messerschmitt P6 reversible pitch propellor to be used as air brake, only prototypes
• U2 GM-1 boost
• U3 MW 50 boost
• U4 30 mm MK 108 engine-mounted cannon

Common Rüstsatz numbers

• R1 belly bomb rack for 250 or 500 kg bomb
• R2 wing bomb racks for 4x 50 kg bombs or 2x WGr21 rockets (or, for the G-1 to G-4 series, recon equipment)
• R3 belly drop tank (300 l)
• R4 two 30 mm MK 108 underwing gunpods
• R6 two 20 mm MG151/20 underwing gunpods

Known Variants

• G-1 (Pressurized fighter)
  • G-1/R2 (Lightened high altitude fighter - GM1, and armor removed)
  • G-1/U2 (High altitude fighter with GM1)
  • G-1 Trop (Never actually existed a “made up” version)
• G-2 (Light fighter)
  • G-2/R1 (Fighter-bomber- 2 underwing drop tanks, extra tail wheel)
  • G-2/R2 (Reconnaissance fighter)
  • G-2 Trop (Tropicalized fighter)
• G-3 (Pressurized fighter based on G-1 with new radio equipment, only 50 built)
• G-4 (Reconnaissance fighter)
  • G-4/R2 (Reconnaissance fighter)
  • G-4/R3 (Reconnaissance fighter)
  • G-4 Trop (Tropicalized Reconnaissance fighter)
  • G-4/U3 (Reconnaissance fighter with MW50)
  • G-4y (Command fighter)
• G-5 (Pressurized fighter)
  • G-5/U2 (High altitude fighter with GM1 boost)
  • G-5/U3 (Fitted with MW-50)
  • G-5/AS (High altitude fighter with DB605AS)
  • G-5y (Command fighter)
• G-6 (Light fighter)
  • G-6/R2 4x 50 kg wing bombs (fighter bomber), or two Wfr.Gr. 21 rockets (heavy fighter)
  • G-6/R3 (Reconnaissance fighter)
  • G-6/R6 (Heavy fighter - two additional 20 mm guns)
  • G-6 Trop (Tropicalized fighter)
  • G-6/U2 (Fitted with GM-1)
  • G-6/U3 (Fitted with MW-50)
  • G-6/U4 (MK108 30 mm engine cannon)
  • G-6y (Command fighter)
  • G-6/AS (High altitude fighter with DB605AS)
  • G-6/ASy (High altitude command fighter)
  • G-6N (Night fighter, usually with R6 and FuG 350Z Naxos)
  • G-6/U4 N (as G-6N but with 30 mm MK 108 engine cannon)
• G-8 (Reconnaissance fighter as G-6, but with camera installation behind cockpit, reduced armament in some planes)
• G-10 (Light fighter with DB605D/DM/DBM engine)
  • G-10/R5 (Reconnaissance fighter)
  • G-10/R6 (Heavy fighter - two additional 20 mm guns)
  • G-10/U4 (Fitted with MK 108 30 mm engine cannon)
• G-12 (Two-seat trainer, built from older G-1/G-5)
  • G-12/R3 (300l drop tank)
• G-14 (Light fighter, evolution of G-6)
  • G-14/R6 (Heavy fighter - two additional 20 mm guns);
  • G-14/AS (High altitude fighter with DB605ASM);
  • G-14/ASy (High altitude command fighter);
  • G-14y (Command fighter);
  • G-14/U4 (Fitted with MK 108 30 mm engine cannon)
• G-16 (Fighter Bomber); based on G-14 with additional armor - production started but soon after war was over

Bf 109H

The Bf 109H was intended to be a high-altitude fighter, developed from the Bf 109F series. The wingspan was increased to 11.92 m, the stabilizer again received a strut leading to the fuselage, and it was also widened. Maximum speed was 750 km/h at 10,100 m. A small number of Bf 109 H-1s were built, flying several sorties in France. Bf 109 H-2 and H-5 developments were also planned, before the entire H-series was scrapped because of wing flutter problems.

Bf 109K "Kurfürst"

Most of the planes of the Bf 109K "Kurfürst" or "Konrad" series saw duty. This series was the last evolution of the Bf 109. The K series was a response to the bewildering array of series, models, modification kits and factory conversions for the Bf 109, which made production and maintenance complicated and costly - something Germany could ill-afford late in the war. The RLM ordered Messerschmitt to rationalise production of the Bf 109, consolidating parts, types etc to produce a uniform, standard model with better interchangeability of parts and equipment. This was to have started in the later models of the G series, but things went in quite the opposite direction. The RLM told Messerschmitt, in effect, to try harder, and the K series was born. Work on the new version began in 1943, and the prototype was ready by the autumn of that year. Series production started in August 1944 due to delays with continuous changes and the new DB605D powerplant. Operational service began in October 1944, and large numbers - approximately 200 - were delivered to frontline units by the end of the month. By the end of January 1945, despite continuous heavy fighting, over 300 K-4s - about every 4th 109 - were listed on hand with the 1st line Luftwaffe units.

In the K-6, K-8, K-10 and the K-14 the armament saw some changes. The K-6, K-8 was planned to carry two MG 131 above its engine, one MK 108 in each wing and a MK 108 engine mounted cannon. The engine gun was changed in the K-10 and replaced by the high-velocity 30 mm MK 103m cannon.

Only the K-4 saw action in numbers, approximately 1,700 being delivered by factories before the end of hostilities. Some sources point to limited use of the K-14 variant or K-4s with two-staged high altitude engines towards the war, however these are hard to confirm. Armament of the K-4 consisted of a 30 mm MK 108 engine-mounted cannon with 65 rounds and two 13 mm MG 131 in the nose with 300 rounds each, and there was the capacity to carry additional equipment such as a droptank, bombs up to 500 kg, underwing 20 mm gondolas or 210 mm rockets (as on the Gustav models); the latter two however were rarely used due to marauding Allied fighters calling for performance.

The Bf 109 K-4 was the fastest 109 of WWII reaching ~715 km/h (445 mph) at 7,500 m altitude; improved propellers were being developed when the war ended which would boost the speed to 727 km/h (452 mph), or even 741 km/h (460 mph). Rate of climb was outstanding, up to 5,800 ft/min at 1.98ata, and 5,500 ft/min at 1.8ata. With such improvements in performance, the Bf 109 remained comparable if not superior to the highest performance Allied or Soviet fighters until the end of the war. Unfortunately the deteriorating ability of the thousands of novice Luftwaffe pilots by this stage of the war made the 109's strengths were of little value against the numerous and well-trained Allied fighter pilots.

Bf 109T "Trägerflugzeug" (carrier aircraft)

Prior to the war the German Navy had become fascinated with the idea of the aircraft carrier. Borrowing ideas from the British and Japanese (mainly the Akagi), they started the construction of the Graf Zeppelin (not to be confused with the airship Graf Zeppelin) as part of Plan Z in 1936. The air group for the carrier was settled on Messerschmitt Bf 109T fighters and Ju 87T dive bombers. The suffix 'T' denoting carrier, 'träger' in German, use.

Initially ten Bf 109E-3 were ordered to be modified to Bf 109T-0 standard. This included, adding a tail-hook, catapult fittings, structural strengthening, manually folding wings and increased wingspan (to 11.08 m). Also the landing gear track was a little wider. Thus prepared, the Bf 109T probably would have been proven much better for carrier operations than the British Supermarine Seafire, a hardly modified landplane that suffered from a bad accident rate flying from carriers.

Following the flight tests, especially the catapult tests, a series of 70 T-1 with DB601N engine was to be produced at Fieseler in Kassel, but after seven T-1 were built, the carrier project was canceled. The remaining 63 of 70 T-1 were built as T-2 without carrier equipment and some of the T-0 and T-1's may have been "upgraded" to T-2 standard. These planes were assigned to I/JG.77, deployed in Norway. The decision to base them in Norway was made primarily by the conditions on the Norwegian landing strips. These landing strips being both short and subject to frequent, powerful cross-winds. Some time after the unit was ordered to turn over thier aircraft to a test unit that was training on the Drontheim-Fjorde strip and recieved E-3's as replacements. The armament of the Bf 109T consisted of two MG 17 above the engine and one MG FF/M cannon in each wing.

Interest in the Graf Zeppelin returned when the value of aircraft carriers became obvious, and in 1942 the ship was back in the yards for completion. By this time the Bf 109T was hopelessly outdated and a new fighter would be needed. Messerschmitt responded with the updated Me 155A series, but work on the ship was again canceled and the Me 155 was later re-purposed as a high-altitude interceptor.

Bf 109Z "Zwilling"

This experimental aircraft was essentially two Bf 109F airframes (together with outer wing panels) joined together by means of a new wing, and new tail section. Two variants of this aircraft were proposed, one being an interceptor armed with five 30 mm cannons, and the other a fighter-bomber with a 1,000 kg bomb load. Only one Bf 109Z was ever built, and it was never flown, having been destroyed in an Allied bombing raid while in hanger.

Bf 109W "Wasserflugzeug" projekt

Contrary to popular belief, the Bf 109W was made-up after the war and is entirely fictional.

• [1]
• [2]

Combat service with Finland

In 1943, the Finnish Air Force received its first Bf 109s. 162 aircraft of this type were to be purchased and the first aircraft landed in Finland on 13 March 1943. In total, 159 aircraft were taken into service, as two G-6s and one G-8 were destroyed en route to Finland. Of these, 48 were G-2s, 109 were G-6s and 2 were G-8s. Bf 109 is still the aircraft that has served in the largest numbers in the Finnish Air Force. The aircraft was called "Mersu" in popular speech and carried the designation MT and a 3-digit identification number. With the arrival of the 109s, the fight was anew more equal as they could match the latest Soviet fighters. The last of the purchased aircraft arrived in Finland on 20 August 1944, just before the armistice with the Soviet Union.

During the Continuation War, Bf 109s were in service with fighter squadrons 24, 28, 30 and 34:

Finnish Bf 109G tally:

		HLeLv 24	HLeLv 28	HLeLv 30	HLeLv 34
Victories		304	15	3	345
Losses in combat		14	0	2	18

The Finns scored 667 confirmed victories with the type, while losing 34 Bf 109s to enemy fighters or AA-fire. A further 16 were lost in accidents and 8 aircraft were destroyed on the ground. 23 pilots were lost.

102 Bf 109s survived the war and the aircraft was to be the main fighter of the Finnish Air Force for almost a decade after the end of the second World War. Due to the aircraft's short life span (it was built as a wartime aircraft and was calculated to last about 100-200 flight hours), it was taken out of service in spring 1954 and the FAF entered the jet age. The last flight was conducted on 13 March 1954 by Major Erkki Heinilä in the aircraft MT-507.

Museum aircraft in Finland

• One Bf 109 (MT-452) is on display at the airfield in Utti.
• Central Finland Aviation Museum displays the Bf 109 that performed the last flight in the FAF (MT-507).
• The Finnish airplane constructor Valtion Lentokonetehdas also manufactured a fighter, VL Pyörremyrsky, whose appearance greatly resembled the Bf 109 but which also features some significant improvements, e.g. significantly easier handling, different wing construction and re-designed landing gear. One single aircraft was produced before the end of the war and that aircraft is today displayed at the Central Finland Aviation Museum.

The doctoral thesis by the productive Finnish aircraft expert Hannu Valtonen is called "Tavallisesta kuriositeetiksi - Kahden Keski-Suomen Ilmailumuseon Messerschmitt Bf 109 -lentokoneen museoarvo" (From regular to a curiosity - The museal value of two Messerschmitt Bf 109s at the Central Finland Aviation Museum).

Combat service with Switzerland

Switzerland took delivery of its first Bf 109s in 1938 when 10 Bf 109Ds were delivered. After this, 80 E-3 were purchased which arrived from April 1939. During the war a further four 109s (two Fs and two Gs) were acquired by the Swiss Air Force through internment.

In April 1944 12 further G-6 aircraft were acquired in exchange for the destruction of a highly secret Messerschmitt Me 110G nightfighter which made an emergency landing in Switzerland. The Swiss Air Force used their Bf 109Gs until 1946.

During the war the Swiss aircraft were painted in more and more colorful markings to avoid confusion with German 109s.

On 10 May 1940 air combat between Switzerland and Germany was initiated. Several Swiss Bf 109s engaged a German Dornier Do 17 near the border at Bütschwil; in the ensuing exchange of fire, the Dornier was hit and eventually forced to land near Altenrhein. The scene was repeated on 16 May when a German He 111 returned from France by way of Swiss airspace. Two Swiss fighters jumped the light bomber when it dropped below cloud cover to de-ice its wings. The German aircraft was hit by machine gun fire and was further damaged by anti-aircraft fire near Zürich. Two injured flyers parachuted; the other two crew members went down with the plane and were captured.

On 1 June when the Germans sent 36 He 111s through Swiss airspace, Switzerland sustained its first casualty. Sub Lieutenant Rudolf Rickenbacher was killed when his Bf 109 caught fire after being hit in the fuel tank by enemy fire.

On 8 June a C-35 observation plane, a relic biplane, was attacked over the Jura Mountains by two German Bf 110s. The pilot and observer were killed. Later on the same day, Swiss Captain Lindecker led about fifteen Swiss fighters against twenty-eight German planes. The Swiss pilots again displayed their ability in air to air combat, knocking three of the German planes from the sky and severely wounding the crew in a fourth. A Swiss Bf 109 was hit and damaged in the dogfight.

Combat service with Yugoslavia

Me-109 E-3 from 6th fighter regiment of Royal Yugoslav Air Force, April 1941.

In 1939 Yugoslavia received 73 Bf 109E-3s in exchange for iron, copper and chrome ore. However the aircraft were grounded most of the time due to a lack of spares. The Yugoslav pilots were not happy with their new fighters. There were a lot of landing accidents due to the Messerschmitt's narrow landing gear. When the Germans invaded in April 1941 the Royal Yugoslav Air Force put up a fight but could do little to repel the invaders.

By the end of the war 17 109s were left. These were stored until 59 more were acquired from Bulgaria. The new Yugoslav Air Force used a mix of G-2, G-6, G-10 and G-12 aircraft until about the middle of 1952.

Developments after World War Two

Messerschmitt 109G-6/U4/R3 Wk.n.163824 on display at the Australian War Memorial.

After the war, some Bf 109s were produced in Czechoslovakia as the Avia S-99 and Avia S-199. These were modified Bf 109G-14s, the latter with a Junkers Jumo 211F engine. As noted above Czech pilots who had previously flown Spitfires for the RAF nicknamed the aircraft 'the Mule'. Several of these aircraft were sold to Israel, forming the basis of the nascent Israeli air force. [3] These aircraft were used by Israel until the end of the 1940s, some flying in combat against Egyptian Spitfires, [4] until being finally replaced by a mixture of P-51 Mustang and Spitfires.

File:AVIA-S 199.jpg

Avia S199 (postwar Czechoslovakian variant) in Muzeyon Heyl ha-Avir, Israel.

In Spain, two versions of the Bf 109G-2, the Hispano Aviacion Ha 1112 "Tripala" and "Buchon", [5] were built under license, the former with the Hispano-Suiza engine, and later with the same Rolls-Royce Merlin engines which had powered Spitfires. Many of these aircraft have been used for theatrical purposes, posing as Emils and Gustavs in Battle of Britain and Tuskegee Airmen, respectively. These modifications were carried out in the Hispano Aviacion factory in Seville.

The original Bf 109, produced before 1945, remained in service for many years after the war. The former German ally Romania used its Bf 109s until 1955. The Finnish Air Force did not retire their Bf 109Gs until March 1954. Hungarian 109s, conversely, were destroyed in Germany by their own crews on 6 May 1945. The Spanish Hispanos, however, flew longer. Some were still in service into the late 1960s. They appeared in films (notably The Battle of Britain) playing the role of the Bf 109. Some Hispano airframes were sold to museums, which rebuilt them as Bf 109s. The Swiss used their Bf 109Gs well into the 1950s.

Operators

Hispano Aviacion Ha 1112 Buchon, the second and last Spanish version built by Hispano Aviacion

Country	In service	Number
Bulgaria		19 × E-3, 145 × G
Croatia
Finland	3/1943	48 × G-2, 109 × G-6, 2 × G-8
Germany	1937	All models
Hungary		40 × E-3
Italy	1943	+300 × G-6/10/12/14, some K-4
Japan		2 × E-3, 2 × G + 1 of other types
Romania		70
Slovakia		16 × E-3
U.S.S.R.		5 × E-3
Spain
Switzerland	1938	10 × D-1, 80 × E-3, 12 × G-6 + others
Yugoslavia	1939	73 × E-3

Postwar users inlude Czechoslovakia, Finland, Israel and Spain.

Specifications (Messerschmitt Bf 109 G-6)

Data from The Great Book of Fighters and the Finnish Air Force Bf 109 Manual

General characteristics

• Crew: One

Performance Armament

• 2×13 mm MG 131 machine guns Rheinmetall-Borsig
• 1×20 mm MG 151/20 cannon (or 1x 30 mm MK 108, G-6/U4)
• 1×300 l (78 US gal) drop tank or 1×250 kg (550 lb) bomb or 4×50 kg (110 lb) bombs (G-6/R1)
• 2×Wfr. Gr.21 rockets (G-6 with R2)
• 2×30 mm MK 108 underwing cannon pods (G-6 with R4)
• 2x 20 mm MG 151/20 underwing cannon pods (G-6 with R6)

External links and sources

• The History of German Aviation: Willy Messerschmitt - Pioneer of Aviation Design, ISBN 0-7643-0727-4
• Bf 109 Restoration
• Bf 109 Aircraft Variations
• Luftwaffe Archive
• The 109 Lair
• Bf 109 Pictures
• 109F-4 documents
• [6]
• Photo gallery of Messerschmitt Bf 109G-5
• Kurfürst! - Resource on Messerschmitt Bf 109 performance. Contains wartime performance trials, and other Bf 109 related documentation.
• Neil Page's web site - translated German pilot accounts and exclusive material on the leading Reich's defence Geschwader JG 300

Related content

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