Republic F-105G Thunderchief The F-105, nicknamed the "Thud," evolved from a 1951 project by to replace the F-84F fighter-bomber. The prototype first flew in October 1955, and Republic delivered the first production aircraft to the U.S. Air Force in 1958. Republic also developed a fully combat-capable two-seat trainer version, the F-105F, and 143 of them in 1963-1964. The Thunderchief on display began operational service in 1964 as a standard F-105F. In 1967 it joined the 355th Tactical Fighter