It was originally designed as a single-seat, nuclear-attack aircraft; a two-seat Wild Weasel version was later developed for the specialized Suppression of Enemy Air Defenses (SEAD) role against surface-to-air missile sites.

[1] As a follow-on to the Mach 1 capable North American F-100 Super Sabre, the F-105 was also armed with missiles and a rotary cannon; however, its design was tailored to high-speed low-altitude penetration carrying a single nuclear weapon internally.

The single-engine F-105 could deliver a bomb load greater than some American heavy bombers of World War II such as the Boeing B-17 Flying Fortress and Consolidated B-24 Liberator.

Meanwhile, the two-seat F-105F and F-105G Wild Weasel variants became the first dedicated 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.

[4] It was conceived of as an internal project to produce a replacement for the RF-84F Thunderflash, which first used the characteristic wing-root air intakes to make room for cameras in the nose section.

The design team led by Alexander Kartveli examined some 108 configurations before settling on a large, single-engine AP-63FBX (Advanced Project 63 Fighter Bomber, Experimental), specifically AP-63-31.

[13] Specifically, insufficient power and aerodynamic problems with transonic drag, as well as Convair's experience with their F-102, had led to a redesign of the fuselage to conform to the area rule, giving it a characteristic "wasp waist".

[14] The F-105's reworked air intake was designed with a unique forward-swept shape, which was derived from Antonio Ferri's work on the proposed Republic XF-103 ramjet-powered interceptor.

During November 1961, production of the type was cut in favor of the USAF adopting the Navy's F-4 Phantom II,[27] and in the longer term, the General Dynamics F-111 Aardvark of the TFX program.

[33] The F-105 had been designed for a short nuclear campaign, leading to shortcomings that became evident in a lengthy conventional war, such as a poor hydraulics layout and fuel tanks that were not self-sealing.

The bomb bay measured 15 feet 10 inches (4.83 m) by 32 in (0.81 m) by 32 in (0.81 m); it was originally designed to carry a single nuclear weapon but typically held an additional 350 US gal (1,300 L) fuel tank.

[44] Based on combat experience, the F-105D was updated with a better ejection seat, additional armor, improved gun sights, and Electronic Counter Measures (ECM) pods on the wings.

[22] Former North American F-86 Sabre pilot Jerry Noel Hoblit recalled being in awe of the F-105's size after seeing it for the first time; he could not manage to reach the air intake lip even with a running jump.

[45] F-105 pilot Colonel Jack Broughton said of the nickname: "The Thud has justified herself, and the name that was originally spoken with a sneer has become one of utmost respect through the air fraternity".

These aircraft were used for all-weather and night low-level strikes against especially dangerous targets by a unit from the 13th Tactical Fighter Squadron (1966–1975) dubbed "Ryan's Raiders" starting in April 1967.

[citation needed] In 1965, the USAF began operating two-seat North American F-100F Super Sabres specially equipped for Suppression of Enemy Air Defenses (SEAD) missions in Vietnam.

[57] However, the F-100F was an interim solution, since its limited payload often required multiple aircraft to conduct a successful strike; it also lacked the speed and endurance to effectively protect the F-105.

[58][59] The resulting EF-105F Wild Weasel III[N 1] (the EF designation was popularly used but unofficial[59]) supplemented its sensors and electronic jamming equipment with AGM-45 Shrike anti-radiation missiles and conventional bombs, giving it an offensive capability lacking in the F-100F.

[62] The F-105G incorporated a considerable amount of new SEAD-specific avionics, including an upgraded Radar Homing and Warning (RHAW) system which required a redesign of the wingtips.

[25][67] In 1964, modified F-105Bs with ballast replacing the cannon, fuselage and wing reinforcement for aerobatics, and the addition of a smoke generator, briefly flew with the United States Air Force Thunderbirds demonstration team.

[73] Many of the issues were worked out during the production run and by 1964, early F-105Ds were upgraded with these fixes under Project Look Alike, although engine failures and fuel system problems persisted until 1967.

The Look Alike upgrades increased the aircraft's capacity from four to 16 conventional 750 lb (340 kg) bombs on underwing and fuselage centerline hardpoints and added the equipment to launch AGM-12 Bullpup air-to-ground missiles.

[79] In a foreshadowing of its Wild Weasel role, the first F-105D combat mission of the war involved an attack on 14 August 1964 against an anti-aircraft artillery site on Plaine des Jarres.

[86][87] USAF Chief of Staff General John P. McConnell was "hopping mad" to hear that two F-105s had been shot down by Korean War-era subsonic North Vietnamese MiGs.

F-105s flying in the vicinity of Hanoi would routinely travel around mountainous terrain nicknamed Thud Ridge to evade the air defenses surrounding the city.

[95][96] Flying low-altitude missions and conducting dive bombings forced the F-105s into range of North Vietnamese anti-aircraft guns, sometimes coming under heavy fire.

[44] One F-105F is unofficially credited with downing three MiGs—one by air-to-air missile, the second by cannon fire and the third by jettisoning the centerline rack full of bombs directly into the path of a surprised MiG.

But the flight leader, Lt Col James "Black Matt" Matthews, came back for the single-file pass and exceeded the speed of sound at less than 100 feet.

[100] Two Wild Weasel pilots received the Medal of Honor: As production of F-105s had ended, the type was replaced in the Vietnam War by other aircraft, primarily the F-4 Phantom II.