Messerschmitt Bf 109

The Bf 109 grew out of the specification with which the Reichsluftfahrtministerium sought, in the mid-1930s, a modern single-seat fighter to replace the biplanes then in service. The requirement was demanding for its day: a critical altitude of 6,000 metres was to be reached in no more than seventeen minutes, and the aircraft was to have an operational ceiling of 10,000 m, with power supplied by the new Junkers Jumo 210 of about 522 kW (710 PS). The intended armament was either a single 20 mm cannon mounted in the engine vee and firing through the propeller hub — the Motorkanone arrangement that would accompany the type throughout its life — or a pair of synchronised machine guns above the cowling.

The team led by Willy Messerschmitt at Bayerische Flugzeugwerke answered with a low-wing monoplane of all-metal construction, enclosed cockpit and retractable undercarriage: the combination of features that would define the fighter of the following decade. The first prototype, Versuchsflugzeug 1 or V1, carrying the civil registration D-IABI, was completed by May 1935, but the German engines intended for it were not ready. To get the design into the air the ministry acquired four Rolls-Royce Kestrel VI engines by trading Rolls-Royce a Heinkel He 70 Blitz for use as an engine test-bed; Messerschmitt received two of them and adapted the engine mounts of V1 to take the British V-12 upright. The irony is worth stating plainly: the fighter that would face the Spitfire for the whole war first flew behind a Rolls-Royce engine.

The comparison against its rivals came at Travemünde, where in 1936 the Arado Ar 80 V3, the Focke-Wulf Fw 159 V3, the Heinkel He 112 V4 and the Bf 109 V2 were flown head to head. The He 112 arrived first, in early February, and the remaining prototypes followed by the end of the month. The Bf 109 initially unsettled fighter pilots accustomed to open-cockpit biplanes: enclosed canopy, high wing loading, narrow-track undercarriage and trailing-edge flaps were all unwelcome novelties. Those same decisions — the smallest, lightest airframe wrapped around the most powerful engine available — gave the design the growth margin that sustained ten years of development.

The first production series, powered by the Jumo 210 in its several versions, served to mature the airframe rather than to deliver a definitive fighter. Changes accumulated in propeller, cooling, armament and fuel system while the engine the design really wanted — the larger-displacement Daimler-Benz — was awaited. The B, C and D series were in practice the operational test bed of an aircraft still unfinished, and the pre-war output reflects it: a total of 2,193 Bf 109 A–E was built before the war, from 1936 to August 1939.

The Bf 109 entered combat in the Spanish Civil War with the Condor Legion from the middle of 1937, and there it gained what no test establishment could give it: real tactical experience. Both the technical fixes and the employment doctrine that came out of that campaign — the loose pair-and-section formation — went with the German fighter arm into 1939 with a running start over its opponents.

The second baptism was a propaganda one. Between 23 July and 1 August 1937, at the fourth International Flying Meeting held at the Dübendorf military airfield near Zurich, six Bf 109s competed against aircraft and pilots from other nations within a deliberately large German entry, and won the events they took part in. The message reached European staffs more clearly than any intelligence report: Germany already had a front-line fighter.

The first deep redesign came with the E series, the *Emil*, which also included the naval variant Bf 109T (T for *Träger*, carrier). The Emil introduced the structural changes needed to accommodate the heavier and more powerful Daimler-Benz DB 601, rated at 1,100 PS (809 kW; 1,085 hp), together with heavier armament and increased fuel capacity. The later sub-variants added fighter-bomber capability and provision for a standardised 300-litre drop tank, using the higher-output DB 601N.

The Emil first saw service with the Condor Legion during the last phase of the Spanish Civil War and was the main variant from the beginning of the Second World War until mid-1941. It also exposed the type's most quoted structural limitation: a combat radius of some 300 kilometres on internal fuel, the consequence of a 660 km range, which in the summer of 1940 left German bombers without effective escort over much of England. On 31 August 1940, 375 E-1s were reported on strength, excluding JG 77; no flying quality could compensate for the fuel the aircraft did not carry, and the shortfall shaped the campaign more than any handling comparison did.

The second big redesign, worked out during 1939 and 1940, produced the F series. The *Friedrich* received new wings, a redesigned cooling system, a cleaner cowling and a cantilever tail that dispensed with the stabiliser lift struts of earlier models; those improved aerodynamics were retained by every later variant. The DB 601E of the F-3 and F-4 was paired with a VDM propeller of broader blades for better altitude performance, and was initially restricted to 1,200 PS at 2,500 rpm until its full rating of 1,350 PS was cleared for service use in February 1942, running on standard 87 octane B-4 aviation fuel.

Some Fs were used late in the Battle of Britain in 1940, but the variant came into common use only in the first half of 1941. Among pilots the Friedrich is usually regarded as the balance point of the whole design: the best compromise between power, armament and aerodynamic refinement before growing weight began to tell.

The G series, the *Gustav*, was introduced in mid-1942 and became by far the most numerous. Its initial versions, G-1 through G-4, differed from the Friedrich only in minor details, most notably the more powerful DB 605 of 1,475 PS (1,085 kW; 1,455 hp). Odd-numbered variants were built as high-altitude fighters with a pressurised cockpit and GM-1 boost, while even-numbered variants were unpressurised air-superiority machines.

The G-6 was the emblematic and most numerous sub-variant, with some 12,000 built from March 1943 — more than a third of all Bf 109s produced. Luftwaffe personnel nicknamed it *Die Beule*, "the bump", after the bulged cowling covers required to clear the breeches of the 13 mm MG 131 machine guns, a feature later cowling versions eliminated. The Gustav also illustrates the drift of the programme: every new requirement — heavy anti-bomber armament, armour, radio equipment, *Rüstsätze* field kits slung under the wings — added weight and drag to an airframe conceived for less than half the power it now carried.

Total Bf 109 production was 33,984 units, of which 30,573 were built between September 1939 and May 1945; a second accounting, closing in April 1945 and covering all airframes built from 1936, gives 34,248, the figure that makes it the most produced fighter aircraft in history. Fighter production accounted for 47% of all German aircraft production, and the Bf 109 for 57% of all German fighter types built.

Those numbers have a side no data table records: part of the production took place in concentration camps through slave labour. In January 1943, as part of the effort to increase fighter output, Messerschmitt licensed the SS-owned company DEST to manufacture Bf 109 parts, and production at Flossenbürg began in February. The number of prisoners working for Messerschmitt increased greatly after the bombing of the Regensburg plant on 17 August 1943. Erla, a Messerschmitt subcontractor, established its own Flossenbürg subcamps, among them Johanngeorgenstadt, set up in December 1943 to produce Bf 109 tailplanes. The dispersal of the industry under Allied bombing and the resort to forced labour are inseparable from the type's production record.

The last series to reach significant production sought to rationalise a range that had fragmented into dozens of sub-variants and field kits. The standardisation attempt proved a failure, but the result offered improved combat performance: MW 50 water-methanol boosting raised output to 1,800 PS (1,324 kW), and the clear-view *Erla Haube* canopy became a standard installation. Top speed was 573 km/h at sea level and 665 km/h at 5 km altitude. Some projected K-series models, such as the K-6, were designed to carry 30 mm MK 108 cannon in the wings, armament intended to bring down four-engined bombers with a short burst.

The world speed record contest of the later 1930s was fought out between German manufacturers. The Bf 109 itself opened the series: on 11 November 1937 the V13, registered D-IPKY and flown by Messerschmitt's chief test pilot Dr Hermann Wurster, reached 610.95 km/h on a racing DB 601R of 1,230 kW (1,672 PS), an airframe converted from a Bf 109 D; it was the first time Germany had taken the world air speed record for landplanes with piston engines. Hans Dieterle beat the preceding mark at 746.61 km/h with the He 100 V8, and Messerschmitt soon regained the lead: on 26 April 1939 Flugkapitän Fritz Wendel, flying the Me 209 V1, set a new record of 755.14 km/h. For propaganda purposes the Me 209 V1 was given the designation Me 109R, a prefix never used for wartime Bf 109 fighters. The record aircraft was not a Bf 109 and shared with it little beyond the manufacturer and the deliberate wish to conflate the two in the public mind.

The Bf 109 was flown by the three top-scoring fighter aces of all time, who claimed 928 victories between them while flying with Jagdgeschwader 52, mainly on the Eastern Front. The highest-scoring, Erich Hartmann, was credited with 352 victories. It was also flown by Hans-Joachim Marseille, the highest-scoring ace of the North African campaign, who shot down 158 enemy aircraft in about a third of the time. Such totals need their context: they reflect both the aircraft's qualities and a rotation system that kept German pilots in combat without relief until death or capture, in contrast to the Allied practice of returning them to training duties.

The type remained in service to the end of the conflict in 1945 and continued to be operated by several countries for many years afterwards.

With the war over, the 109 went on being built outside Germany. In Czechoslovakia it was produced as the Avia S-99 and S-199; twenty-five S-199s served with Israel in 1948 and formed the basis of the fledgling Israeli Air Force, one of the most quoted ironies in the aircraft's history. In Spain two versions derived from the Bf 109G-2 were built under licence: the Hispano Aviación HA-1112 "Tripala", with a Hispano-Suiza engine, and the HA-1112 "Buchón", with the same Rolls-Royce Merlin that had powered the Spitfire.

The final variant, the HA-1112-M1L Buchón — the name of a breed of pouter pigeon — first flew on 29 March 1954 with a 1,600 hp Rolls-Royce Merlin 500-45 and a four-bladed Rotol propeller, both bought as surplus from the United Kingdom. The Merlin's chin intake altered the characteristic line of the nose. It was an improvised assembly of parts of disparate origin, but it turned the German fighter's descendant into a British-engined aircraft and, by that route, into the natural supplier of "Messerschmitts" for the war films of the following decades.

The Bf 109 combines two conditions rarely found together: it was the most produced fighter in history and it stood in the front line from the first day of the war to the last. Its formula — the smallest possible airframe around the most powerful available engine — explains both its virtues and its faults: excellent power-to-weight ratio and climb, and at the same time a narrow-track undercarriage responsible for a high number of take-off and landing accidents, especially among pilots given abbreviated training in the final phase of the war.

The survivors today are divided between original airframes and their Spanish and Czechoslovak descendants. Preserved HA-1112s include static examples, such as the HA-1112-K1L at the Museo del Aire in Madrid, and airworthy ones, some of them re-engined and modified to resemble the German Bf 109. Telling an authentic Bf 109 from a Buchón, and a Buchón from a "converted" Buchón, is one of the points where the paperwork deserves more attention than the silhouette.