European thinking during that time frame was supercharged liquid cooled engines for fighter aircraft because of the aerodynamics....radials presented more drag in comparison. Mr Tank designed the 190 with a very close cowled radial in order to streamline the front end. They had a lot of overheating problems in the first couple of attempts before the fan was installed, and still had to open up the opening from the original design. Although I do like the radials and especially the idea Tank came up with, there is a very distinctive sound to the Merlin and Griffon that is quite pleasing!