The Republic F-105 Thunderchief, was a supersonic fighter-bomber used by the United States Air Force. It was commonly known as the "Thud" by its crews. The Mach 2 capable F-105 bore the brunt of strike bombing over North Vietnam during the early years of the Vietnam War, and has the dubious distinction of being the only US aircraft to have ever been removed from combat due to high attrition rates. Originally designed as a single-seat, nuclear-attack aircraft, a two-seat Wild Weasel version was later developed for use in the specialized Suppression of Enemy Air Defenses (SEAD) role against surface-to-air missile sites.

As a follow-on to the Mach 1 capable F-100, the F-105 was also armed with missiles and a cannon; however, its design was tailored to high-speed low-altitude penetration carrying a single nuclear weapon internally. First flown in 1955, the Thunderchief entered service in 1958. As the largest single-engined fighter ever employed by the USAF, the single-seat F-105 would be adapted to deliver a greater bomb load than the four-engined, 10-man strategic bombers of World War II like the B-17 and B-24.

The F-105 would be best remembered as the primary strike bomber over North Vietnam in the early stages of the Vietnam War. Over 20,000 Thunderchief sorties were flown, with 382 aircraft lost (nearly half of the 833 produced) including 62 operational losses. Although they lacked the agility of the smaller MiG fighters, USAF F-105s were credited with 27.5 kills, of which 24.5 were by cannon.

During the war, the single-seat F-105D was the primary aircraft delivering the heavy bomb loads against the various military targets. Meanwhile, the two-seat F-105F and F-105G Wild Weasel variants became the first dedicated Suppression of Enemy Air Defenses (SEAD) platforms, fighting against the Soviet-built S-75 Dvina (NATO reporting name: SA-2 Guideline) surface-to-air missiles. Two Wild Weasel pilots were awarded the Medal of Honor for attacking North Vietnamese surface-to-air missile sites, with one shooting down two MiG-17s the same day. The dangerous missions often required them to be the "first in, last out", suppressing enemy air defenses and keeping them suppressed while strike aircraft accomplished their missions and then left the area.

Although the F-105 weighed 50,000 pounds (23,000 kg), the aircraft could exceed the speed of sound at sea level and Mach 2 at high altitude. It could carry up to 14,000 lb (6,400 kg) of bombs and missiles. The Thunderchief was later replaced as a strike aircraft over North Vietnam by both the McDonnell Douglas F-4 Phantom II and the swing-wing General Dynamics F-111 Aardvark. However, the "Wild Weasel" variants of the F-105 remained in service until 1984, when they were replaced by a specialized F-4G "Wild Weasel V".

Source: Wikipedia, "Republic F-105 Thunderchief", available under the CC-BY-SA License.