[Crumpp]

Ok, from December of 1939 it was introduced.

I read that thread.

You have a copy of the Bf-109E Flugzeug handbuch where the automatik propeller is covered and included from December 1939. That means it was in use on the aircraft from December 1939 forward. Probably even sooner as the normal procedure is a Technical bulletin is issued until the POH is republished and updated. It also does not tell us the extent of operational use.

IIRC, VDM did not produce both types concurrently. The automatic propeller superseded the variable pitch only propeller in VDM production and as the propellers were overhauled, they were upgraded.

It also seems the claim is being made the propeller was not introduced until September 1940. That claim introduces a translated OKL document that raises the rpm limit for the engine and instructs that only Mtt and VDM can modify the governor for the new rpm limits. Both companies are working as fast as possible to make the necessary modifications to comply with the new rpm limits.

That document does not say a thing about the introduction timeline of the VDM propeller "mit automatik" and does not shed any light on the extent of propellers use operationally.