The Republic F-105 Thunderchief was the first supersonic tactical fighter-bomber developed from scratch. Apart from being the biggest single-seat, single-engine combat aircraft in history, the F-105 was notable for its large internal bomb bay and unique swept-forward engine inlets in the wing roots. The wing was highly swept and incorporated low-speed ailerons and high-speed spoilers for lateral control, and a droop-snoot leading edge.
Known as "the Thud", this greatest of all single-engine combat jets bore a huge burden throughout the Vietnam War, and was a deadly and effective tactical fighter-bomber. A supersonic jet, the Thud is characterized by two unique systems: it is the only jet fighter to refuel from a side-fuselage boom, and was the first jet fighter to employ a Vulcan 20mm "Gatling Gun" cannon. The D-model made more air strikes against North Vietnam than any other US aircraft, and also suffered more losses. During the war, the versatile Thud was also credited with 25 MiG kills.