The Messerschmitt Bf 109 emerged as a formidable presence in the theater of World War Two, etching its mark as one of the most renowned warplanes of its time. Adaptable in roles ranging from fighter to fighter-bomber and reconnaissance craft, the Bf 109 became emblematic of the aerial confrontations that defined the era. Taking flight for the first time in 1935, it swiftly found its place within the ranks of Nazi Germany’s Luftwaffe, where it remained steadfast until the war’s conclusion in May 1945. As one of the select few combat aircraft in active production and deployment at the war’s outset, it endured as a stalwart fixture on the front lines throughout the conflict.
At the forefront of the Bf 109 lineage stood the Gustav series, with the G variant holding particular prominence. Serving as a marked improvement over its predecessor, the Bf 109F, the Gustav line commenced operational deliveries with the G-1 model in the midst of 1942. The G-6 variant, chief among its brethren, saw production across various factories, showcasing diverse layouts and accommodating an array of production-line and field modifications. With a staggering production tally exceeding 12,000 units, the G-6 epitomized the pinnacle of Bf 109 manufacturing.
Powered by Daimler-Benz engines, the Bf 109G-series marked the third major iteration of the aircraft, succeeding the DB 601-equipped Bf 109E and F models. Employing the potent DB 605 engine, boasting greater power and efficiency, the Gustav series initially adopted the DB 605A variant, generating approximately 1,475 horsepower for takeoff. The G-6 shared close kinship with its parallel counterpart, the G-5, the primary divergence being the inclusion of cockpit pressurization in the latter. This innovation facilitated higher altitude operations, albeit through comparatively rudimentary means, yet remained a feature exclusive to a scant few units when juxtaposed with the prolific Bf 109G-6.
Straightforward start
At the outset, the G-6 came into existence in two discernible variants: the conventional Bf 109G-6 and the Bf 109G-6 trop. The latter featured a specialized filter positioned atop its supercharger air intake on the port side of the engine cowling. This filter served to obstruct the intrusion of fine sand or dust into the supercharger, tailored specifically for deployment in North Africa. Its utility extended to operations conducted during arid and dusty summers in certain regions of the Soviet Union. Nevertheless, as the G-6 underwent a protracted production phase, a plethora of distinct sub-types emerged over time, bearing notable deviations from the initial models manufactured.
Apart from Messerschmitt’s primary production of the G-6 at Regensburg in Bavaria, the aircraft was also assembled by various other manufacturers. These included Wiener Neustädter Flugzeugwerke (WNF) in Austria, Erla Maschinenwerk GmbH in Leipzig, located in eastern Germany, and Magyar Waggon- és Gépgyár (MWG) in Györ, a steadfast ally of Germany. A network of smaller companies spread across Germany and its occupied territories supplied components to these final assembly lines. The production span of the G-6 roughly encompassed the period from February 1943 to June 1944, although evidence suggests the existence of a production batch as late as November 1944.
Varied upgrades
The Bf 109G-6 marked a significant enhancement in armament for the Bf 109 aircraft line. Unlike its predecessors, including earlier models of the ‘Gustav’ series, which were equipped with two 7.92mm MG 17 machine guns mounted in the upper forward fuselage, the G-6 variant featured a substitution of these with two 13mm MG 131 machine guns. This alteration necessitated a wider installation, resulting in prominent bulges on each side of the fuselage, extending partially onto the engine cowling panels and forward fuselage sides. These additions, colloquially referred to as ‘Beule’ in German, denoting a bump or bulge, altered the aircraft’s profile.
Despite retaining the established centrally mounted 20mm MG 151/20 cannon firing through the propeller hub, the introduction of these new machine guns significantly boosted the firepower of the G-6. However, this upgrade came with a drawback. The overall weight increase, which had been a persistent issue in the Bf 109 series since the Bf 109E model, had a pronounced impact on the G-6, resulting in a degradation of its overall performance.
Extra equipment
Rüstsatz, known in plural as Rüstsätze and abbreviated as ‘R’, constituted field modification kits crafted for diverse Luftwaffe combat aircraft during World War Two. These kits, often supplied in package form directly from the manufacturer of the aircraft, facilitated on-site alterations. Consequently, Rüstsatz kits could be installed at airfield maintenance levels. In contrast, Umrüst-Bausätze kits (abbreviated as ‘U’) were notably dissimilar, usually being integrated at the factory. Nevertheless, this distinction was not absolute; throughout production runs, various Rüstsätze kits were frequently applied by factories to address specific operational requisites.
By and large, Umrüst-Bausätze kits were more intricate and necessitated the specialized expertise and tools available on the production line. One of the most renowned Rüstsätze modifications involved the addition of a fairing, often referred to as a ‘gondola,’ beneath each wing, housing a 20mm MG151/20 cannon. This configuration, commonly denoted as Rüstsatz 6 or R6 field modification, is frequently abbreviated in published sources as Bf 109G-6/R6.
However, some sources contend that this modification lacked an official designation of that sort and did not alter the aircraft’s formal designation – while others designate this alteration as R5 rather than R6. Regardless of the terminology, it is widely acknowledged that the G-6s equipped as such were sometimes colloquially termed ‘gunboats’. Undoubtedly, they were formidable fighters, with the existing 20mm MG 151/20 firing through the propeller hub and two 13mm MG 131 machine guns in the upper forward fuselage being effectively complemented by the two underwing cannons.
From the summer of 1943 onwards, G-6s manufactured by WNF were outfitted with a centrally mounted 30mm MK 108 cannon firing through the propeller hub, replacing the established 20mm MG 151/20 in that position. These aircraft were designated as Bf 109G-6/U4.
During the same period, a novel anti-bomber armament was introduced for use by the G-6. This comprised the 210mm Werfer-Granate 21 (WGr 21), featuring a single sizable air-to-air unguided rocket projectile, with one mounted in a conspicuous external tube beneath each wing. These robust rockets boasted a substantial warhead weighing approximately 90lb. They were conceived as a ‘stand-off’ weapon against US heavy bomber formations, being fired from a distance of roughly 3,900ft – well beyond the effective range of the bombers’ defensive armament. In exigent circumstances, the tubes could be discarded via an explosive charge.
Other noteworthy Rüstsatz additions encompassed the installation of a 300 liter drop tank beneath the fuselage (R3) to mitigate the renowned comparatively limited range and endurance of the Bf109 across its various operational iterations. The R1 designation pertained to a fighter-bomber conversion with a limited number of aircraft equipped with an ETC 500 bomb rack beneath the fuselage. The designations R2 and R3 were occasionally employed to denote camera-equipped reconnaissance fighters manufactured by WNF.
Major alterations
Numerous notable alterations were implemented in the design and equipment of the G-6 variant throughout its extensive production period. Among these changes was the integration of a distinctive feature known as the ‘tall tail’. This innovation entailed replacing the Bf 109’s conventional metal vertical tailplane and fabric-covered metal-framed rudder, which featured an angled hinge line, with an entirely new wooden unit. The original metal vertical tail, a hallmark of the Bf 109 since its inception, was substituted with this wooden counterpart. Despite being of greater weight compared to its predecessor, the new wooden tailplane boasted a straight vertical rudder hinge line. This modification compounded the mounting weight issues faced by the G-6 variant. However, it was crafted from ‘non-strategic’ materials, primarily wood, owing to Nazi Germany’s constraints on metal usage towards the latter stages of the war. The transition to the wooden vertical tail occurred gradually throughout 1944, with many earlier G-6 models retrofitted with the new tail during major overhauls at repair and maintenance facilities.
The introduction of the larger ‘tall tail’ was notably observed in the production batch bearing Werk Nummer 163 000 and beyond, distinguishing many late-war Bf 109s of the G-6 lineage and subsequent iterations. For the pilots of the Gustav series, significant cockpit modifications were also instituted during the Bf 109G’s production tenure, particularly concerning the cockpit cover. Previous iterations suffered from compromised rearward visibility due to the pilot’s fixed head armor, composed of solid metal, within the cockpit canopy.
Starting in the late summer of 1943, a gradual transition began towards a modified head armor design, incorporating a glazed section, famously known as the ‘Galland Armor’, in homage to the renowned German fighter ace, Adolf Galland. Furthermore, a groundbreaking change was introduced from late 1943 or early 1944 onward, manifesting in an entirely revamped cockpit canopy design. Departing from the characteristic heavily framed canopy, a new, less cumbersome unit with enhanced glazing was introduced, replacing both the heavily framed opening section and the fixed rear portion present in earlier Bf 109 iterations.
Often cited in historical accounts as the ‘Galland Hood’, the new canopy was actually designated the ‘Erla Haube’, available in several variations of curved transparent structures. While typically featuring the Galland Armor behind the pilot’s head, alternative armor configurations were occasionally installed. The innovative canopy, akin to its predecessor, retained the starboard-edge hinge mechanism, albeit with a more streamlined appearance.
The modification to the canopy of the G-6 aircraft brought about a corresponding adjustment to the fuselage radio mast, which was associated with the FuG 16Z radio equipment. Some planes saw this mast relocated to the fuselage spine, while others maintained its original position at the rear end of the canopy frame. In certain instances, there was no mast present, with the aerial wire directly attaching to the fuselage spine. Additionally, in this area of the aircraft’s structure, a prominent ‘d/f loop’ was installed on the spine for the Peilrufanlage radio navigation aid, along with a whip aerial for the FuG 25a Erstling IFF equipment.
A small subset of G-6 aircraft were equipped with supplementary FuG 16ZY radio gear, designated for formation leaders tasked with controlling groups of fighters during specific missions. These aircraft carried a ‘Morane’ aerial mast beneath the port wing, resulting in the rarely used Bf 109G-6Y designation.
Furthermore, a limited number of G-6s were outfitted with the FuG 350Z-series Naxos direction-finding receiver for rudimentary night-fighting capabilities. This receiver homed in on radar signals emitted by RAF night-flying bombers, with its aerial positioned on the aircraft’s spine within a large fitting covered by a protective transparent cover. Additionally, a circular indicator unit was installed in the cockpit for the pilot’s reference.
Another significant alteration introduced during the production of the Bf 109G-6 was the adoption of a taller, non-retracting tailwheel leg in place of the shorter, non-retracting unit it replaced. This feature became a notable distinguishing characteristic of late-war Messerschmitt fighters. Although the production batch believed to have initiated this modification was numbered 167,000 onwards, no specific aircraft designation change was officially documented for these late-production G-6s.
Engine changes
During the manufacturing period of the G-6, several notable advancements reshaped its capabilities significantly. Foremost among these innovations was the enhancement of its power system. Initially, this manifested through the introduction of additional power options for the DB 605A engine. Two variants of supplementary power emerged, with the GM-1 nitrous oxide boost being the more prevalent, leading to the designation of Bf 109G-6/U2 for the converted aircraft. Alternatively, the MW 50 methanol-water boost was available, reserved for the Bf 109G-6/U3 model. Utilizing MW 50 power boost could elevate the DB 605A engine’s output to approximately 1,770hp with C3 96-100 Octane fuel. However, irrespective of the boost additive employed, its usage was limited to short durations rather than the entire flight. Nonetheless, it significantly augmented the G-6’s top speed, enabling it to reach approximately 386mph at altitudes exceeding 22,000ft.
Although these supplementary systems conferred improved performance upon the G-6, the most pivotal development was the introduction of a specialized derivative of the DB 605 engine, designated as DB 605AS. This variant was engineered specifically for high-altitude operations, facilitating the G-6’s ability to ascend to the altitudes frequented by USAAF heavy bombers, thereby enhancing its combat effectiveness against them. While the Focke-Wulf Fw 190A also contributed to anti-bomber efforts, its performance at high altitudes was limited due to its air-cooled BMW 801 radial engine, thus placing a greater reliance on the G-6 for high-altitude engagements against American heavy bombers.
The primary modification to the DB 605-series engine of the G-6, along with its associated equipment, entailed the integration of an enlarged and more potent supercharger. Upon installation of the DB 605AS engine, the designation transitioned to Bf 109G-6/AS. While some of these aircraft were newly manufactured by Messerschmitt in Regensburg from May to August 1944, many were conversions from existing G-6 airframes.
Aircraft equipped with the AS engine featured distinctive alterations to the upper forward fuselage and adjacent fuselage sides, primarily to accommodate the enlarged supercharger. Notably, the Beule blisters, originally necessitated by the installation of MG 131 machine guns on standard DB 605A-powered Bf 109G-6s, were seamlessly integrated into the upper cowling shape for AS-powered aircraft. This refinement significantly improved aerodynamic efficiency by streamlining the fuselage and incorporating streamlined panels to create a sleeker profile.
Furthermore, G-6s fitted with the DB 605AS engine were outfitted with a new high-altitude propeller unit, the VDM 9-12159, characterized by broader blades designed to generate greater power output and torque. This upgrade replaced the previous VDM 9-12087 propellers, enhancing the performance of the high-flying AS-powered G-6s. The utilization of C3 96-100 Octane fuel was imperative for achieving the required boost pressure from the supercharger to attain the necessary horsepower for optimal altitude performance, crucial for competing with US heavy bombers and their escort fighters.
The heightened power output of the AS engine necessitated the incorporation of a wooden tall tail on late production G-6s. The enlarged rudder area provided improved lateral control, addressing the increased power and heightened performance, particularly at elevated altitudes.
Operational highs and lows
The G-6 was introduced into Luftwaffe service during the initial months of 1943 and remained operational until the conclusion of the conflict. Its deployment to frontline units commenced in February 1943, primarily within the Mediterranean theater, as the German hold on North Africa gradually loosened amidst fierce combat. Noteworthy among the participating units were JG (Jagdgeschwader or fighter wing) 27, 51, 53, and 77, all seasoned formations engaged in combat since the early stages of the war.
The first recorded instance of a G-6 loss occurred on March 4, 1943, when a aircraft from the 5th Staffel of JG 53 (5./JG 53) was downed.
One of the initial encounters of a G-6 falling into Allied possession appears to involve an aircraft from 6./JG 51, designated Yellow 13, a G-6 trop model that made a forced landing in Tunisia during April 1943, preceding the cessation of hostilities in North Africa the following month.
Subsequent allocations of G-6s to Luftwaffe fighter units in Germany and Western Europe followed, with similar distribution occurring on the Eastern Front, although this was somewhat delayed until production significantly increased. The G-6 gradually supplanted earlier models of the Gustav series.
Eventually, nearly all fighter units operating the Bf 109 received G-6s, along with various reconnaissance units. These included, among others, JG 1, 2, 3, 4, 5, 6, 11, 25, 26, 50, 52, 54, 76, 300, 301, and 302, alongside numerous smaller and ad hoc fighter units. Recce squadrons comprised NAG (Nahaufklärungsgruppe or short-range reconnaissance group) 1, 2, 3, 4, 5, 8, 11, 12, 13, 14, and 15. Additionally, two night-fighter units, NJG (Nachtjagdgeschwader or night-fighter wing) 10 and 11, operated G-6s, albeit not as their primary equipment. JG 1, 5, and 11 were among the initial recipients of the Bf 109G-6/AS variant, with deliveries commencing from late spring 1944 onwards. Subsequently, JG 3, 27, and 302 also received examples.
The G-6 played a prominent role in all major air battles and campaigns of the later stages of the war. Alongside the Focke-Wulf Fw 190A fighter, it bore the brunt of aerial warfare, increasingly challenging for the Germans as the tide turned against them. With the Luftwaffe’s fighter arm stretched thin, combating the Soviet forces in the East while contending with US daylight bombers and their escorts in the West, the strain on resources was evident.
Following the Allied invasion of France on June 6, 1944, the German forces faced significant setbacks, placing the Bf 109 force under mounting pressure. Losses of experienced pilots, irreplaceable in their skill, forced Luftwaffe fighters into the hands of inexperienced aviators hastily deployed to replace the growing casualties. With US fighters defending bombers while actively seeking engagements with the Luftwaffe, losses became unsustainable.
