If anyone is familiar, there was a reconnaissance version of the P-61 Black Widow called the F-15 Reporter, which had an elongated nose for housing spy cameras like that of the reconnaissance P-38 Lightning (F-5) and P-80/F-80 Shooting Star (F-14, later FP-80/RF-80). The "F" letter meant photo reconnaissance because before the USAAF became the USAF in September 1947, "F" denoted reconnaissance aircraft (after 1948, "F" was replaced for "R" for reconnaissance planes when the USAF ordered the use of the "F" letter for fighters as it broke with past policy of classifying fighters as pursuit planes rather than simply fighter planes). Just 36 F-15s were built, but they were vital in aerial reconnaissance over Korea during the Korean War.