F-105 Thunderchief

Republic Aviation initiated the F-105's development in 1951 as an internal project aimed at replacing the RF-84F Thunderflash. The design team, led by Alexander Kartveli, evaluated 108 configurations before selecting the AP-63FBX, specifically design AP-63-31. This aircraft was conceptualized for supersonic, low-altitude penetration missions, primarily intended to deliver a single, internally carried nuclear weapon. Republic prioritized low-altitude speed, range, and payload capacity over traditional fighter maneuverability for this role. The company submitted its proposal in April 1952, leading to a USAF contract for pre-production engineering and an initial order for 199 aircraft. By March 1953, the order was revised to 37 fighter-bombers and nine reconnaissance variants. A mock-up inspection in October 1953 found no need for major modifications. The initial engine choice, the Allison J71 turbojet, was subsequently replaced by the more powerful Pratt & Whitney J75. The program faced a temporary suspension in late 1953 but was officially reinstated on June 28, 1954, with a new order for 15 F-105s. The first prototype, the YF-105A, conducted its initial flight on October 22, 1955. Following significant damage to the first prototype, a second YF-105A flew on January 28, 1956. Aerodynamic challenges, coupled with insights gained from Convair's F-102 program, prompted a redesign incorporating the area rule, resulting in the aircraft's characteristic "wasp waist" fuselage. The redesigned air intake system, influenced by Antonio Ferri's work, combined with the J75 engine to enable the F-105B model to achieve Mach 2.15. In March 1956, the USAF ordered 65 F-105Bs and 17 RF-105Bs. The first pre-production YF-105B flew on May 26, 1956, and the first production F-105B was formally accepted by the USAF on May 27, 1957. Republic Aviation requested the name Thunderchief in June 1957, which was officially adopted by the USAF the following month.

The F-105 was configured as a mid-wing monoplane with a 45° sweep angle on both the wing and tail surfaces. It utilized a single engine fed by two intakes located within the wing roots, a design that kept the nose clear to accommodate a radome for the multi-mode radar. The fuselage was designed to carry 1,184 US gallons of fuel internally and included a bomb bay. This bomb bay, measuring 15 feet 10 inches by 32 inches by 32 inches, was originally intended to hold a single nuclear weapon but was more commonly used to carry an auxiliary 350 US gal fuel tank. External ordnance could be carried on five hardpoints: four located under the wings and one on the centerline of the fuselage. The two inner wing pylons and the centerline pylon were plumbed to accept fuel from 450 and 650 US gal drop tanks, respectively. The two outer wing pylons were wired for the carriage of missiles or bombs but were not plumbed for fuel tanks. The F-105 was equipped with one M61 Vulcan 20 mm 6-barrel Gatling-style cannon mounted in the left side of the nose, supplied with 1,028 rounds. Features such as improved ejection seats, additional armor, and updated gun sights were incorporated into the F-105D model, based on combat experience.

The aircraft possessed a total ordnance capacity of up to 14,000 lb (6,400 kg). Beyond the internal bay's utility for nuclear weapons or an auxiliary 390 US gal (1,500 L) fuel tank, external carriage included AIM-9 Sidewinder missiles on the outer wing pylons for air-to-air defense. Air-to-surface capabilities included the carriage of AGM-12 Bullpup missiles, AGM-45 Shrike anti-radiation missiles, M117 and Mark 80 series general-purpose bombs, M118 demolition bombs, cluster munitions, and various nuclear weapons, including the B28, B43, B57, and B61.

The F-105 Thunderchief was extensively deployed in the Vietnam War, serving as a principal attack platform. It flew over 20,000 strike sorties during the conflict. Initial missions included attacks on anti-aircraft artillery positions in Laos and bridge interdiction in North Vietnam. The single-seat F-105D bore the primary burden of strike missions, delivering substantial bomb loads against military targets. The two-seat F-105F and later F-105G "Wild Weasel" variants were specifically developed for and pioneered the Suppression of Enemy Air Defenses (SEAD) mission, targeting Soviet-designed S-75 Dvina (SA-2 Guideline) surface-to-air missile sites. Two Wild Weasel aircrew members were awarded the Medal of Honor for their actions while engaging SAM sites. Despite its significant operational contributions, the F-105 experienced heavy losses in Southeast Asia, with 382 aircraft lost out of a total production run of 833; 62 of these losses were due to operational incidents rather than combat damage. USAF F-105s achieved 27.5 air-to-air kills against North Vietnamese aircraft. In the latter stages of the conflict, the F-105 was progressively replaced in the primary strike role by aircraft such as the McDonnell Douglas F-4 Phantom II and the General Dynamics F-111 Aardvark. However, the specialized F-105G Wild Weasel variant continued in service until early 1984.

Main Variants:

• F-105B: The initial production model, equipped with the AN/APN-105 navigational radar, with 71 aircraft built.

• F-105D: The definitive production model, featuring enhanced all-weather capabilities enabled by advanced avionics including the AN/APN-131 navigational radar, with 610 built.

• F-105F: A two-seat trainer variant derived from the F-105D, incorporating a lengthened forward fuselage, dual controls, a taller vertical stabilizer, and retaining full combat capability with increased takeoff weight; a total of 143 were built.

• EF-105F: The initial designation for a Wild Weasel/Defense suppression version, with 54 aircraft converted from the F-105F airframe.

• F-105G: The definitive two-seat Wild Weasel variant, representing an improved version of the EF-105F equipped with dedicated suppression of enemy air defenses (SEAD) avionics systems.

Missiles payload:

• Air-to-Surface AGM-12 Bullpup
• Air-to-Air Short-Range Raytheon AIM-9 Sidewinder

Bombs payload:

• Thermonuclear B28 (脡U : Mk 28)