The 109 remained in production from 1937 through 1945 in many different variants and sub-variants. The primary engines used were the Daimler-Benz DB 601 and DB 605, though the Junkers Jumo 210 powered most of the pre-war variants. The most-produced Bf 109 model was the 109G series (more than a third of all 109s built were the G-6 series, 12,000 units being manufactured from March 1943 until the end of the war).^[48]

The initial production models of the A, B, C and D series were powered by the relatively low-powered, 670–700 PS (660-690 HP) Junkers Jumo 210 series engines. A few of prototypes of these early aircraft were converted to use the more powerful DB 600.^[49]

The first major redesign came with the E series, including the naval variant, the Bf 109T (T standing for Träger, or carrier). The Bf 109E, or "Emil", introduced structural changes to accommodate the heavier, but significantly more powerful 1,100 PS (1,085 HP) Daimler-Benz DB 601 engine, heavier armament, and increased fuel capacity. Partly due to its limited 300 km (186 mile) combat radius on internal fuel alone, resulting from its 660 km (410 mile) range limit,^[50] later variants of the Es introduced a fuselage ordnance rack for fighter-bomber duty, or provision for a long-range, standardized 300 litre (79 US gallon) drop-tank, and used the DB 601N engine of higher power output.^[51] The 109E 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 World War II until mid-1941 when the 109F replaced it in the pure fighter role.^[52] (Eight 109Es were assembled in Switzerland in 1946 by the Dornier-Werke, using licence built airframes; a ninth airframe was assembled using spare parts.)^[53]

The second major redesign during 1939–40 gave birth to the F series. The "Friedrich" had a complete redesign of the wings, the cooling system, and fuselage aerodynamics, and was powered by the 1,175 PS (1,159 HP) DB 601N (F-1, F-2) or the 1,350 PS (1,332 HP) DB 601E (F-3, F-4). Considered by many as the high-water mark of Bf 109 development, the F series abandoned the wing cannon and concentrated all armament in the forward fuselage with a pair of synchronized machine guns above and a single 15 or 20 mm Motorkanone-mount cannon behind the engine, the latter firing between the cylinder banks and through the propeller hub, itself covered by a more streamlined, half-elliptical shaped spinner that better matched the streamlining of the reshaped cowling, abandoning forever the smaller, conical spinner of the Emil subtype. The F-type also omitted the earlier stabilizer lift strut on either side of the tail. The F-subtype's improved aerodynamic configuration was used by all subsequent variants. Some Bf 109Fs were used late in the Battle of Britain in 1940, but the variant only came into wide use in the first half of 1941.^[54]

Bf 109 Gustav cockpit

The G series, or "Gustav", was introduced in mid-1942. Its initial variants (G-1 through G-4) differed only in minor details from the Bf 109F, most notably in the more powerful 1475 PS (1,455 HP) DB 605 engine. Odd-numbered variants were built as high-altitude fighters with a pressurized cockpit and GM-1 boost, while even-numbered variants were not pressurized, air superiority fighters, and fighter-bombers. Long-range photo-reconnaissance variants also existed. The later G series (G-5 through G-14) was produced in a multitude of variants, with uprated armament and provision for kits of packaged, generally factory-installed parts known as Umrüst-Bausätze (usually contracted to Umbau) and adding a "/U" suffix to the aircraft designation when installed. Field kits known as Rüstsätze were also available for the G-series, but those did not change the aircraft designation. By early 1944, tactical requirements resulted in the addition of MW-50water injection boost and high-performance superchargers, boosting engine output to 1,800–2,000 PS (1,775-1,973 HP). From early 1944, some G-2s, G-3s, G-4s, and G-6s were converted to two-seat trainers, known as G-12s. An instructor's cockpit was added behind the original cockpit and both were covered by an elongated, glazed canopy.^[55]

The final production version of the Bf 109 was the K series, or "Kurfürst", introduced in late 1944, powered by the DB 605D engine with up to 2,000 PS (1,973 HP). Though externally akin to the late production Bf 109G series, a large number of internal changes and aerodynamic improvements was incorporated that improved its effectiveness and remedied existing flaws, keeping it competitive with the latest Allied and Soviet fighters.^[5][56] The Bf 109's outstanding rate of climb was superior to many Allied adversaries including the P-51D Mustang, Spitfire Mk. XIV, and Hawker Tempest Mk. V.^[57]

• Crew: 1
• Length: 6.13 m (20 ft 1 in)
• Wingspan: 9 m (29 ft 6 in)
• Height: 3.25 m (10 ft 8 in)
• Wing area: 14.5 m² (156 sq ft)
• Airfoil: TsAGI R-II (16% at root)^[60]
• Empty weight: 1,490 kg (3,285 lb)
• Gross weight: 1,941 kg (4,279 lb)
• Powerplant: 1 × Shvetsov M-63 9-cylinder supercharged air-cooled radial engine, 820 kW (1,100 hp)
• Propellers: 2-bladed variable-pitch propeller

Performance

• Maximum speed: 525 km/h (326 mph; 283 kn) at 3,000 m (9,800 ft)
• Range: 700 km (435 mi; 378 nmi)
• Service ceiling: 9,700 m (31,800 ft)
• Rate of climb: 14.7 m/s (2,890 ft/min)
• Time to altitude: 5,000 m (16,000 ft) in 5 minutes 48 seconds
• Wing loading: 134 kg/m² (27 lb/sq ft)
• Power/mass: 0.35 kW/kg (0.21 hp/lb)

Armament

• 2 × fixed forward-firing 7.62 mm (0.300 in) ShKAS machine guns in upper cowling
• 2 × fixed forward-firing 20 mm (0.787 in) ShVAK cannon in the wings
• 6 × unguided RS-82 rockets or up to 500 kg (1,100 lb) of bombs