Artist: © Mikhail Bykov
The Bf 109 G-series was developed from the largely identical F-series airframe, although there were detail differences. Modifications included a reinforced wing structure, an internal bullet-proof windscreen, the use of heavier, welded framing for the cockpit transparencies, and additional light-alloy armour for the fuel tank. It was originally intended that the wheel wells would incorporate small doors to cover the outer portion of the wheels when retracted. To incorporate these the outer wheel bays were squared off. Two small inlet scoops for additional cooling of the spark plugs were added on both sides of the forward engine cowlings. A less obvious difference was the omission of the boundary layer bypass outlets, which had been a feature of the F-series, on the upper radiator flaps.
Like most German aircraft produced in World War II, the Bf 109 G-series was designed to adapt to different operational tasks with greater versatility; larger modifications to fulfil a specific mission task like long-range reconnaissance or long-range fighter-bomber were with “Rüststand” and given a “/R” suffix, smaller modifications on the production line or during overhaul like equipment changes were made with kits of pre-packaged parts known as Umrüst-Bausätze, usually contracted to Umbau and given a “/U” suffix. Field kits known as Rüstsätze were also available but those did not change the aircraft designation. Special high-altitude interceptors with GM-1 nitrous oxide injection high-altitude boost and pressurized cockpits were also produced.
The newly fitted Daimler-Benz DB 605A engine was a development of the DB 601E engine utilised by the preceding Bf 109 F-4; displacement and compression ratio were increased as well as other detail improvements to ease large-scale mass production. Takeoff and emergency power of 1,475 PS (1,455 hp, 1,085 kW) was achieved with 1.42 atm (42.5 inches/6.17 lbs) of boost at 2,800 rpm. The DB 605 suffered from reliability problems during the first year of operation, and this output was initially banned by VT-Anw.Nr.2206, forcing Luftwaffe units to limit maximum power output to 1,310 PS (1,292 hp, 964 kW) at 2,600 rpm and 1.3 atm manifold pressure (38.9 inches/4.4 lbs). The full output was not reinstated until 8 June 1943 when Daimler-Benz issued a technical directive. Up to 1944, the G-series was powered by the 1,475 PS Daimler-Benz DB 605 driving a three-blade VDM 9-12087A variable-pitch propeller with a diameter of 3 m (9.8 ft) with even broader blades than used on the F-series. Pitch control, as on the 109F, was either electro-mechanical (automatic) or manual-electric using a thumb-switch on the throttle lever. From 1944 a new high-altitude propeller with broader blades was introduced, designated VDM 9-12159, and was fitted to high-altitude variants with the DB 605AS or D-series engines.
The early versions of the Bf 109G closely resembled the Bf 109 F-4 and carried the same basic armament; however, as the basic airframe was modified to keep pace with different operational requirements, the basically clean design began to change. From the spring of 1943, the G-series saw the appearance of bulges in the cowling when the 7.92 mm (.312 in) MG 17 were replaced with 13 mm (.51 in) MG 131 machine guns (G-5 onwards) due to the latter’s much larger breechblock, and on the wings (due to larger tyres), leading to the Bf 109 G-6’s nickname “Die Beule” (“The Bulge”). The Bf 109G continued to be improved: new clear-view cockpits, greater firepower in the form of the 30 mm (1.18 in) MK 108 cannon were introduced in late 1943; and a new, enlarged supercharger in the high-altitude DB 605AS engine, a larger vertical stabilizer (G-5 onwards), and MW 50 power boost in 1944.
Erich Hartmann, the World’s top scoring fighter ace, claiming 352 victories, flew only the Bf 109G, of which he said:
It was very manoeuvrable, and it was easy to handle. It speeded up very fast, if you dived a little. And in the acrobatics manoeuver, you could spin with the 109, and go very easy out of the spin. The only problems occurred during takeoff. It had a strong engine, and a small, narrow-tread undercarriage. If you took off too fast it would turn [roll] ninety degrees away. We lost a lot of pilots in takeoffs.