[edwest2]

Jukka,

I understand why you are skeptical. Here is a quote from the author's site:

"Professor Doktor-Ing. Karl Kollmann, chief designer at Daimler-Benz aero engines until 1945. The Professor wrote his technical memoirs in 1947 which lay at the family home, almost unknown to the outside world until January 2016, when his son graciously supplied them for me to study.

"Kollmann`s work was central to the engines that would power the Messerschmitt 109 throughout the entire Second World War, and through his fathers writings an unparallelled opportunity exists to form a window in time back to a fighter aircraft engine designers drawing office in the 1940`s."

Best,
Ed