At the end of 1943 Messerschmitt began to look at a
new version of the 109 powered by the new DB 605 D and L engines and
armed with the new MK 103 and MK 108 canon. I addition to this new
powerplant and weapons, the new 109 version was to utilize more wooden
components. Originally the whole wing was to be made of wood but this
proved impractical and in the end only the tailplane and fin was made of
The K-series was to have a fully
retractable tail wheel and completely covered main wheels with new outer
wheel well doors. The bigger wheels necessitated long bulges on the
wing. In the field the outer wheel well doors were often deleted. Due to
material shortage the retractable tail wheel was often not fitted, the
old short G-type tail wheel being fitted instead.
As the DB 605D engine was not yet available the K-1 was powered
by the DB 605A engine. Like with the G-series the odd numbered types of
the K-series were pressurized. The K-1 was armed with an engine mounted
MK 108 and two MG 131 machine guns over the engine. Shortage of MK 108
canon led to the use of MG 151/20 machine guns in some instances.
The unpressurized K-2 was powered by the DB 605A Only a few K-2
airframes were built.
This was a projected pressurized fighter powered by the DB 605AS engine.
In an effort to standardize production of the 109 on one variant
instead of the numerous versions in production the K-4 was designed. As
the K-2 offered little improvement over the G-14 and G-16 the K-4 was
proposed powered by the DB 605D engine. As it was the DB 605D was only
an interim measure. In the long run the use of the even more powerful DB
605L with a four bladed propeller was envisaged. The K-4 was armed with
an engine mounted MK 108 and two MG 131 machine guns over the engine
This was intended as a heavy interceptor to replace the G-6/R4 and R6.
Instead of the under wing mounted guns of these types in the K-6 two
guns were fitted in the wings, giving a total armament of 3x MK 108 and
2 x MG 131. At least one prototype was built.
The K-8 was to be a reconnaissance variant of the K-4 intended to
replace the older G-8. It is not clear of a prototype was built.
The K-10 was to be a K-4 fitted with an engine mounted MK 103 gun.
There is no information about a K-12. Similarity with the G-series
suggest that this would have been a two-seat trainer.
This was the ultimate 109 version fitted with the DB 605L engine driving
a four bladed propeller. At least one 109 flew with a four bladed
propeller in 1945.
R1: An ETC 500 rack under the fuselage
R2: A Rb 50/30 or Rb 70/30 camara fitted vertically in the fuselage
R3: A 300l drop tank under the fuselage
R4: Two underwing MG 151/20
R5: A Rb 32/7x9 camera fitted vertically in the fuselage
R6: A BSK 16 camera fitted in the port wing