10/31/2011.Remarks by Johan Visschedijk: "As the dash "number" system for distinguishing modifications to USAAF aircraft had not been fully developed during the early stages of the Airacobra's career, its designation suffix letters ran far into the alphabet without being accompanied, for some time, by any really major changes. Thus, the 229 P-39Fs delivered were identical to the P-39D apart from having twelve exhaust stubs on each side of the center fuselage instead of the usual six, and an Aeroproducts airscrew instead of the Curtiss Electric type.

Field modifications (additional belly armor and rear-fuselage cameras) to suit the aircraft for ground support duties resulted in the P-39F-2, the pictured aircraft was one of the 27 converted to this format. The aircraft went to the RFC at Ontario, California, USA on January 28, 1945."