http://i38.photobucket.com/albums/e1...00octane_1.jpg
and this is a prewar planning document, and we all know that RAFFC made a wholesale conversion to CS props and 100octane fuel in the spring of 1940 in response to wartime events, especially the improved performance of the Me109. Conversion to 100 octane without changing over to CS props was almost pointless, but a March 1939 planning meeting could not have envisaged the largescale changes that would be required by Spring 1940.