The first of the USAF 'Century jets' to enter service, The F-100 was originally designated Sabre 45. The first prototype made it's initial flight on 25th May 1953, and was followed into the air by the first production version, the F-100A, on 29th October 1953. Out of the 203 F-100As built, 167 were fitted with the Pratt & Whitney J57-P-7, while the remainder had the J57-P-39. Both engine subtypes were rated at 9,700 lb st (4,400 kg st), boosted to 14,800 lb st with afterburning.[1]