Messerschmitt Bf 109K "Kürfurst"

Messerschmitt Bf 109K “Kürfurst” (not “Karl”)


The Bf 109K (code name "Kürfurst" not "Karl")was the final production version of the only German single engined fighter to see service throughout the war.  It was developed in an attempt to streamline the production process and increase the number of fighters being built in Germany. In this it was successful, and some 750 109Ks were built in the last six months of the war. However, as the war came increasing close to Germany many of these aircraft were destroyed before getting into action, while chronic fuel shortages began to cut the amount of time Luftwaffe aircraft could actually spend in the air. The most significant achievement of the 109K is that it existed at all.

Development and Changes

The aim of the team designing the 109K was to pick out the best features from the many versions of the 109G and produce a standard aircraft that would have all of the best features of the earlier aircraft. The 109K was powered by the DB 605D engine, with the possibility to have either MW powerboosting or extra standard fuel. The engine mounted gun was changed to the Mk 108 cannon, used in some later versions of the 109G. The 13 mm MG 131s were retained as the cowling guns. The resulting fighter was roughly twenty miles per hour faster than the Bf 109G-10 at all heights.



The proposed K-2 was almost identical to the G-10, and so was not produced.


This was the main version of the 109K. It first appeared in October 1944, and at least 544 K-4s had been produced by the end of November. Shortages of both the engine and new gun meant that the older 109G remained in production at the same time as the K-4. The exact total of K-4s that were built is unknown. Plans were in place to build over 3,500 by July 1945, but work didn't begin at all of the factories involved.


Several other variants on the 109K were proposed. The K-6 was an interceptor powered by the DB 605 DCM engine. It had two Mk 108 guns in the wings, giving it three 30 mm cannon. It entered production in January 1945, but very few were completed. The extra cannon proved unpopular, dramatically reducing the performance of the aircraft. The few that reached the front often had the wing mounted cannon removed. This was the last version that definitely saw service.


A planned reconnaissance fighter, based around the DB 605 DCM engine. It was armed with one MK 103 cannon in the engine and two MK 108s in the wings, but no cowling guns. It could carry either a single Rb 50/30 camera or two RB 32/7x9 cameras behind the cockpit. Production probably began, but this type probably never entered service.


The K-10 was an up-gunned K-4, with the MK 108 cannon in the engine replaced by the Mk 103 and powered by the DB 605 DCM engine. The war ended before this aircraft could enter service. 


The final proposed version of the Bf 109. This version would have been powered by the DB 605 L engine. The DB 605 L engine was cancelled in November 1944. This version would have been armed with two MG 131 machine guns over the engine cowling, one MG 108 cannon in the engine and two MG 108s in the wings.

Combat Record

 The 109K appeared too late in the war to take part in anything but the final battles to defend Germany. Significant numbers of 109K-4s were involved in the disastrous attacks on 1 January 1945 (Operation Baseplate) that virtually destroyed the German fighter force. Whatever its merits as a fight, the 109K-4 appeared too late and in too small numbers to have any chance against the overwhelming British, American and Russian attacks that it had to face at the end of the war.

Stats (K-4)

DB 605D 12 cylinder inverted V liquid cooled engine (In action 2)

1,800 at take off
1,275 climb and combat at 0 feet
1,150 climb and combat at 25,247 feet
1,040 maximum continuous at 0 feet
1,030 maximum continuous at 25,263 feet

319 mph maximum combat speed at 0 feet
415 mph maximum combat speed at 27,700 feet
360 mph maximum emergency speed at 0 feet
440 mph maximum emergency speed at 24,750 feet
296 mph optimum cruise at 0 feet
400 mph optimum cruise at 27,559 ft

350 miles

32 ft 6.5 in (In action 2)

29 ft 2.5 in (In action 2)

109 in Action 2Messerschmitt Bf 109: Pt. 2 , John R. Beaman, Jr. This second volume continues on from part one, beginning with the Bf 109F, probably the best version of the fighter, and taking the story to the end of the war and beyond. [see more]
cover cover cover
Bf 109B - Bf 109C - Bf 109D - Bf 109E - Bf 109F - Bf 109G - Bf 109H - Bf 109K
Bf 109B - Bf 109C - Bf 109D - Bf 109E - Bf 109F - Bf 109G - Bf 109H - Bf 109K

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How to cite this article: Rickard, J (26 March 2007), Messerschmitt Bf 109K,

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