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Operational History
By 1964, the F-105B was relegated to Air National Guard squadrons. It was replaced in frontline service by the definitive F-105D whose advanced NASARR R-14A radar and AN/ASG-19 Thunderstick fire-control system gave it all-weather performance. The R-14A radar also added a terrain guidance capability. The F-105D entered service with 335th TFS in 1960. Designed for a European conflict with the Soviet Union, the F-105D saw considerable deployment in West Germany to provide NATO with tactical nuclear strike capability, and in Japan. Like the F-105B, the F-105D's early career was plagued with maintenance problems and in-flight failures. The origins of the nickname Thud were far from complimentary — it stood for the sound of an F-105 crashing into the ground. The entire F-105D fleet was grounded in December 1961 and then again in June 1962. 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.
Meanwhile, the USAF was gradually changing the anticipated F-105 mission from nuclear interdiction to conventional bombing. The Look Alike upgrades increased the aircraft's capacity from four to sixteen conventional 750 pound (340 kg) bombs on underwing and fuselage centerline hardpoints and added the equipment to launch AGM-12 Bullpup air-to-ground missiles. In June 1961, an F-105D delivered 7 tons (15,430 lb) of conventional bombs during a USAF test — at the time a record for a single-engine airplane and a payload three times heavier than World War II's four-engined heavy bombers such as the B-17 Flying Fortress and the B-24 Liberator, though aerial refueling would be required for long missions. In fact, one of the F-105Ds was named Memphis Belle II after the famed World War II B-17.
Vietnam War
In spite of a troubled early service life, the F-105 became the dominant attack aircraft during the Vietnam War. The F-105 could carry twice the bomb load further and faster than the F-100, which was used mostly in South Vietnam. In a foreshadowing of its Wild Weasel role, the first F-105D combat mission of the war involved an attack of an anti-aircraft artillery site on Plaine des Jarres. The first Thunderchief of the war was also lost in this mission (the pilot managed to eject safely). The first strike mission took place on 13 January 1965 with the destruction of the Ben Ken bridge in Laos. Following the start of Operation Rolling Thunder on 1 March 1965, a large number of F-105Ds were deployed in Royal Thai Air Force Bases at Khorat and Takhli. On 2 August 1967, F-105Ds from 335th and 338th Tactical Fighter Squadrons made the first of many successful raids on the Paul Doumer bridge. While the planes were first deployed with their original natural metal finish, they so on adopted the distinctive 2-green and tan Vietnam camouflage scheme which blended into the jungle landscape.
On a typical combat mission into North Vietnam, the F-105D carried two 450 US gallon wing-mounted fuel tanks, a 390 US gallon fuel tank in the bomb bay, and five 1,000 pound (454 kg) or six 750 pound (340 kg) bombs, and required inflight refueling both going to and sometimes returning from Hanoi 700 miles (1,125 km) distant. Thunderchiefs made a loop north of Hanoi over a mountain nicknamed the Thud Ridge at high speed and low altitude in order to avoid the heavily defended airspace around the city. Although the ridge provided proper shielding from the North Vietnamese radars and SAMs, the installment of anti-aircraft artillery and a MiG fighter airfield at the southern end of the valley prevented the F-105s from fully exploiting the benefit of cover. The name "Thud Ridge" (also the name of a book by Jack Broughton about the F-105) came from the prominent role of the mountain in F-105 missions.
Medal of Honor recipients
Two Wild Weasel pilots received the Medal of Honor:
– USAF Captain Merlyn H. Dethlefsen was awarded the Medal of Honor and Capt Kevin "Mike" Gilroy the Air Force Cross for an F-105F Wild Weasel mission on 10 March 1967, flying F-105F 63-8352. After their aircraft was damaged by ground fire, Dethlefsen and Gilroy elected to stay in the skies above the steel works at Thai Nguyen until the SAM site was found and destroyed.
– USAF Captain Leo K. Thorsness was awarded the Medal of Honor and Capt Harold Johnson the Air Force Cross for an F-105F Wild Weasel mission on 19 April 1967, flying F-105F 63-8301. Thorsness and Johnson protected an attempted rescue of another Wild Weasel crew that had been shot down, in the process destroying two MiG-17s. After running out of ammunition, Thorsness and Johnson continued to act as decoys to draw the MiGs away from the rescue aircraft.
Retirement
The Thunderchief was rapidly withdrawn from USAF service after the end of the Vietnam War. Only 833 F-105 Thunderchiefs had been built. Having lost nearly 50% of that production figure in Vietnam, the F-105 was by military standards almost no longer combat-effective. Some aircraft remained in service with Air National Guard units, but their extended wartime service meant that many F-105s had already reached or exceeded their service lives by the mid-1970s. The Thunderchief was officially retired on 25 February 1984. The F-105 was replaced by the F-4 Phantom II.
In 1964, specially modified F-105Bs with ballast replacing the Vulcan cannon, a number of fuselage and wing reinforcements for aerobatics, and the addition of a smoke generator, briefly flew with the USAF Thunderbirds demonstration team. After only six shows, a fatal accident from overstressing the airframe forced a switch back to the F-100 Super Sabre.
Sources:
Wikipedia: F-105 Thunderchief
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