Originally Posted by David Brown

Hi Gary:

According to Jerry Crandall's Yellow 10 (The Story of the Ultra Rare FW 190 D-13) published by Eagle Editions Ltd. (highly recommended), there was only one plant dedicated to the production of this aircraft. Arbeitsgruppe Roland was to start manufacturing 1,030 aircraft in January, 1945. In May, 1945 another 1,130 aircraft were to be started.
The Werke Number of "Yellow 10" was 836017 and would suggest that as many as 17 of these aircraft were produced. Unfortunately, production data for the D-13 is rather rare; however, it is known that two D-13's were in service by April 7, 1945.
As to why only a few D-13's entered service, Crandall indicated that delays were caused due to "a lack of documents supplied to various factories and contractors". I would imagine that a lack of supplies, production and transportation interruptions due to bombing and the general overall confusion realized during the last months of the war also played a role.
The oil leakage around the propeller hub and spinner was more of a situation than a problem. The seals in spinner area would loosen over time due to the vibration caused by the firing of the MG 151 20 mm cannon. Crandall also mentions that the cannon required a different hub incorporating a blast tube hole through it and the spinner which in turn contributed to the fluid leakage.
By the way, if you ever get to Seattle make it a point to see the FW190D-13 on display. It's a superb looking fighter.