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The Bf 109 K-4
The Bf 109, designed by Willi Messerschmitt, is a legend alongside the British Spitfire, the American P-51 Mustang and the Japanese Zero.
During the early war years, the Bf 109 was one of the world’s finest single seat fighters. Its basic design provided the potential for it to take new engines and armament so that it remained the backbone of the Luftwaffe fighter forces throughout World War Two.
As explained by Neil Page in his book Luftwaffe Fighters: Combat on all Fronts Volume 1, the last major production variant of the Bf 109 was the K-series constructed primarily at Messerschmitt, Regensburg Externally there was little to distinguish the ‘K’ from, say, a G-10. The K-4, the only variant produced in series, featured only a small number of detail differences from other late-war Bf 109s. Even these featured on earlier variants for the most part – deeper oil cooler, wider propeller blades (WDM 9-12159), Erla Haube. The relocated DF loop (the antenna mast often being dispensed with) and a relocated fuel filler point were innovations introduced on the ‘K.’ A retractable tailwheel and fully covered main wheels on retraction in the wing were also standardised on the K-4.
The Bf 109 K-4 entered production in late 1944 and the first deliveries were made to III. / JG 77. Some 220 were constructed in November 1944, followed by a further 325 in December 1944. By this stage of the war, production of the Bf 109 was planned to end with the RLM concentrating on just a few ‘advanced’ types.
A step backwards
Battered by US bombing raids, what was left of the Regensburg plant was being turned over to jet production – although by this stage much production and assembly was already dispersed to so-called Waldwerke (forest factories’) and even concentration camps where labour was (self- evidently) cheap and plentiful.
Despite the company’s efforts, Messerschmitt never managed widespread introduction of its rationalisation programme – dispersed subcontractor production and quality-control issues, to cite just two reasons, saw to that. The new ‘tall tail’ in particular – constructed from ‘non-strategic but difficult- to-bond wood – caused numerous problems and at war’s end plenty of Bf 109s were of course still flying with the short vertical stabilizer and rudder, not to mention the short tail-wheel strut. In the case of the Bf 109 K-4, only some 200 were equipped with Flettner rudder tabs.
The increased weight of heavier weapons and the various aerodynamic alterations to the airframe to accommodate these along with uprated power plants still caused problems for young pilots going to front units with less than 50 hours on the type. JG 52 ace and post-war aerobatic champion Walter Wolfrum writing about the situation during 1944 recalled: “…In the hands of an experienced pilot the Bf 109 could still be dangerous but how many experienced pilots did we have left? [The Bf 109] was starting to get long in the tooth. Its development had reached its high point with the agile ‘Friedrich’. Since then every planned upgrade and improvement was actually a step backwards.
The end of DB engine development potential
“During the summer of 1944 flew the G-6, in 1945 I – flew the G-14, the G-10 and finally the K-4. The fuselage was strengthened, armament was increased and each time the engine had to be up-rated to compensate. But the DB engine had reached the end of its development potential. The latest variant, the DB 605, was essentially the same DB 601 that had powered the 109 at the outbreak of the war. While the engine had been overhauled it was very vulnerable and breakdowns and failures piled up. When we flew for just three or four minutes at full-throttle and with emergency power, the engine was finished. The average engine life under front conditions was in any case only around 40 hours…
“In addition, we had not made any decisive progress in the armament. The 30mm cannon MK 108, which fired through the propeller hub of the Bf 109, was on paper an absolutely lethal gun and appeared mainly suited to combating the ubiquitous Il-2, but the weapon tended to jam easily. It fired shells weighing 480g at a muzzle velocity of only 550m per second and at a rate of 660 rounds per minute. One could almost observe the trajectory of these heavy, slow projectiles falling away without ever reaching their target – unless you were at very close range. I preferred the old MG 151/20, despite its smaller calibre. You could shoot much more accurately with it…”
Luftwaffe Fighters: Combat on all Fronts Volume 1 is published by Mortons Books and is available to order here.
Photo credit: B. Huber at German Wikipedia and Herbert Ringlstetter via Wikipedia
