The F-84B, which differed from the YP-84A only in having faster-firing
M3 machine guns (later F-84s also had provision to carry eight
High Velocity Aircraft Rockets (HVAR) underwing), became operational with
14th Fighter Group at
Dow Field,
Bangor, Maine, in December 1947. Flight restrictions followed immediately, limiting maximum speed to
Mach 0.8 due to
control reversal, and limiting maximum acceleration to 5.5
g-force (54 m/s2) due to wrinkling of the fuselage skin. To compound the problem, parts shortages and maintenance difficulties earned the aircraft the nickname, "Mechanic's Nightmare". On 24 May 1948, the entire F-84B fleet was grounded due to structural failures in the aircraft's wings. The F-84C featured a somewhat more reliable J35-A-13C engine of the same power as the A-15-C used by the F-84B, and modified fuel and electrical systems. Beyond these modifications, the F-84C was virtually identical to the F-84B, and suffered from the same defects. A 1948 review of the F-84 program discovered that none of the F-84B or F-84C aircraft could be considered operational or capable of executing any aspect of their intended mission. The program was saved from cancellation because the F-84D, whose production was well underway, had satisfactorily addressed the major faults. A fly-off against the F-80 revealed that while the Shooting Star had a shorter takeoff roll, better low altitude
climb rate and superior maneuverability, the F-84 could carry a greater bomb load, was faster, had better high altitude performance and greater range. As a compromise, the USAF in 1949 committed US$8 million to implement over 100 upgrades to all F-84Bs and F-84Cs, most notably reinforcing the wings to a similar standard to the F-84D. Despite the resultant improvements, both the F-84B and F-84C were withdrawn from service during 1952. The structural improvements were factory-implemented in the F-84D, which entered service in 1949. Wings were covered with thicker aluminum skin, the fuel system was winterized and capable of using
JP-4 fuel, and a more powerful J35-A-17D engine with was fitted. It had been discovered that the untested wingtip fuel tanks contributed to wing structural failures by inducing excessive twisting during high-g maneuvers. To correct this, small triangular fins were added to the outside of the tanks. The F-84D was phased out of USAF service in 1952 and left
Air National Guard (ANG) service in 1957. The first effective and fully capable Thunderjet was the F-84E model which entered service in 1950. The aircraft featured the J35-A-17 engine, further wing reinforcement, a fuselage extension in front of the wings and extension aft of the wings to enlarge the cockpit and the avionics bay, an A-1B gunsight with
AN/APG-30 fire-control radar, and provision for an additional pair of fuel tanks to be carried on underwing pylons. The latter increased the combat radius from to over . One improvement to the original F-84 design was rocket racks that folded flush with the wing after the 5-inch HVAR rockets were fired, which reduced drag over the older fixed mounting racks. This innovation was adopted by other US jet fighter-bombers. . Despite the improvements, the in-service rates for the F-84E remained poor with only half of the aircraft operational in April 1950. This was primarily due to a severe shortage of spares for the Allison engines. The expectation was that F-84Es would fly 25 hours per month, accumulating 100 hours between engine overhauls. The actual flight hours for Korean War and NATO deployments rapidly outpaced the supply and Allison's ability to manufacture new engines. The F-84E was withdrawn from USAF service in 1956, serving with the
Air Force Reserve until 1957 and lingering with ANG units until 1959. The final straight-wing F-84 was the F-84G, intended as a stop-gap until the swept wing F-84F entered service, but ordered in large numbers to build-up NATO air forces. It introduced a
refueling boom receptacle in the left wing,
autopilot,
Instrument Landing System, J35-A-29 engine with of thrust, a distinctive framed canopy (also retrofitted to earlier types), and the ability to carry a single
Mark 7 nuclear bomb. The F-84G entered service in 1951, although deliveries were slowed by shortages of engines. Production continued until July 1953 with 3,025 F-84Gs delivered, with 789 going to the USAF and 2,236 to US allies as part of US military aid. The F-84G was retired from the USAF in mid-1960.
Flying the Thunderjet Typical of most early jets, the Thunderjet's takeoff performance left much to be desired. In hot Korean summers with a full combat load, the aircraft routinely required of runway for takeoff even with the help of
RATO bottles (two or four of these were carried, each producing 1,000 lbf (4.4 kN) of thrust for 14 seconds). All but the lead aircraft had their visibility obscured by the thick smoke from the rockets. F-84s had to be pulled off the ground at 160 mph (140 kn, 260 km/h) with the control stick held all the way back. Landings were made at a similar speed. For comparison, the
North American P-51 Mustang landed at approximately 120 mph (100 kn, 190 km/h). Despite the "hot" landing speeds, the Thunderjet was easy to fly on instruments and crosswinds did not present much of a problem. Thanks to the thick straight wing the Thunderjet rapidly reached its
Mach 0.82 limitation at full throttle and low altitude. The aircraft had sufficient power to fly faster, but exceeding the Mach limit at low altitudes resulted in a violent pitch-up and structural failure causing the wings to break off. Above , the F-84 could be flown faster but at the expense of severe buffeting. However, the airspeed was sufficiently easy to control to make safe dive bombing from 10,000 ft possible. The top speed limitation proved troublesome against Soviet
Mikoyan-Gurevich MiG-15s in Korea. Slower than the MiG, the F-84 was also unable to turn tightly with a maximum instantaneous-turn load of only 3 gs followed by rapid loss of airspeed. One F-84E pilot credited with two MiG kills achieved his second victory by intentionally flying his aircraft into
pitch-up. The MiGs chasing him were unable to follow the violent maneuver and one crashed into the ground. Luckily for the F-84E pilot , the aircraft did not disintegrate, but the airframe did suffer heavy warping. The F-84 was a stable gun platform and the
computing gunsight aided in accurate gunnery and bombing. Pilots praised the aircraft for Republic's legendary ruggedness. Pilots nicknamed the Thunderjet "The Lead Sled". It was also called "The Iron Crowbar", "a hole sucking air", "The Hog" ("The Groundhog"), and "The World's Fastest Tricycle", "Ground Loving Whore" as a testament to its long takeoff rolls. F-84 lore stated that all aircraft were equipped with a "sniffer" device that, upon passing
takeoff safety speed, would look for the dirt at the end of the runway. As soon as the device could smell the dirt, the controls would turn on and let the pilot fly off the ground. In the same vein, it was suggested a bag of dirt should be carried in the front landing gear well. Upon reaching takeoff safety speed, the pilot would dump the dirt under the wheels, fooling the sniffer device.
Korean War The Thunderjet had a distinguished record during the
Korean War. After the entry of the
People's Republic of China into the war in October 1950, the US
Fifth Air Force requested that a wing of F-84s be sent to Korea. While the F-84B and F-84C could not be deployed overseas because their J35 engines had a service life of only 40 hours, the F-84D and F-84E were more suitable, and so the F-84E-equipped
27th Fighter Escort Group was sent to the Far East aboard the aircraft carrier , which arrived in Japan on 30 November 1950. After maintenance, the F-84s moved to
Taegu airfield (known as K-2), flying its first operational missions on 7 December 1950. The aircraft were initially tasked with escorting the B-29 Superfortress bombers. The first Thunderjet air-to-air victory was scored on 21 January 1951 at the cost of two F-84s. The F-84 was outmatched by the swept-wing Soviet
Mikoyan-Gurevich MiG-15, which was both faster and more manoeuvrable, and the MiG counter-air mission was soon given to the
F-86 Sabre. The F-84 switched to the ground attack role at which it excelled. The number of units operating the F-84 over Korea gradually increased, both by bringing over Air National Guard Groups from the US, and converting F-80 squadrons already in theater. The F-84 flew a total of 86,408 missions, dropping 55,586 tons (50,427
metric tons) of bombs, 6,129 tons (5,560 metric tons) of
napalm, and firing 22,154 rockets. The USAF claimed F-84s were responsible for 60% of all ground targets destroyed in the war. Notable F-84 operations included the 1952
attack on the Sui-ho Dam. During the war, the F-84 became the first USAF fighter to utilize
aerial refueling. In aerial combat, F-84 pilots were credited with eight MiG-15 kills against a Soviet-claimed loss of 64 aircraft. The total losses were 335 F-84D, E and G models. According to the USAF FY1953 statistical digest, during the Korean war, 305 F-84s were lost, including 249 in combat missions and 56 non-combat losses.
USAF service in Western Europe A notable
incident occurred on 10 March 1953, when two Czech MiG-15 fighters intercepted two US Air Force F-84Es that were claimed to have strayed from German to Czechoslovak airspace and shot one down. It crashed on the German side of the border and the pilot successfully ejected.
Portugal Portugal received its first F-84s in January 1953, with 25 new build F-84Gs later supplemented by USAFE stocks and from other European operators, with deliveries eventually reaching 125 F-84Gs. They were the
Força Aérea Portuguesa's first operational jet fighters. Two squadrons were formed in Portugal, operating the F-84 in both air-defense and ground attack roles, with the Thunderjet also equipping an aerobatic display team, the
Dragões. In 1960, the two operational F-84 squadrons were disbanded and the remaining F-84s transferred to training units. In 1961, however, an
uprising against Portuguese rule began in
Angola, and as a result, 25 F-84Gs were refurbished by
OGMA and sent to Angola, with the first aircraft arriving at
Luanda in August that year. There, they formed the
Esquadra 91 (91st Squadron), carrying out bomb, rocket and gun attacks against separatist forces. In 1966, after
Rhodesia's Unilateral Declaration of Independence, and the imposition of the
Beira Patrol by the British
Royal Navy to attempt to stop the flow of fuel to Rhodesia via the port of
Beira, Mozambique, a detachment of eight F-84s was sent from Luanda to Mozambique to guard against potential clashes with British forces, with the aircraft returning to Angola when the threat of military action receded. Attrition of the F-84s was heavy, and by 1973, only five F-84s remained operational, with the last examples withdrawn from use that year, although the F-84G nominally remained in Portuguese service until October 1975.
Republic of China The
Republic of China Air Force (ROCAF) began operating surplus F-84G Thunderjets acquired from the
United States Air Force in 1953, with the aircraft serving in both ground-attack and interceptor roles amid rising tensions across the Taiwan Strait. Following their introduction, F-84G Thunderjets were primarily employed for low-level strafing missions against
People's Liberation Army (PLA) ground and maritime targets along the Chinese coastline. Meanwhile, RF-84 variants were tasked with tactical reconnaissance operations, gathering intelligence on coastal regions of mainland China. On 21 July 1956, four ROCAF F-84G aircraft from the 4th Squadron, based at Chiayi Air Base, undertook an escort mission over the
Matsu Islands to protect an RF-84 reconnaissance aircraft. The formation was led by Major
Niu Hsun (), and included Lieutenant
Yu Chu () as No.2, Captain
Tsai Yun-Hui () as No.3, and Lieutenant
Ouyang Yi-Fen () as No.4 aircraft. During the mission, the formation encountered
MiG-17 fighters from the 45th Regiment, 15th Division of the
People's Liberation Army Air Force (PLAAF). In the ensuing engagement, Lieutenant Ouyang Yi-Fen distinguished himself by shooting down two MiG-17s—one piloted by
Song Yi-Chun () and the other by
Liu Ye-Chen ()—and damaging two additional MiG-17s. PLAAF records later confirmed that both enemy pilots were killed in action. None of the five ROCAF Thunderjets, include the RF-84 reconnaissance aircraft, were lost or damaged. The engagement, later known as the "21 July Matsu Air Battle," was regarded as a major aerial victory for the ROCAF, showcasing the effective use of the F-84G when operated with tactical flexibility and strong leadership. F-84G units remained active during the
Second Taiwan Strait Crisis in 1958, engaging PLA MiG-15 and MiG-17 fighters in a series of aerial skirmishes. Although both sides sustained losses, the F-84G continued to play a vital role until late 1958, when it was gradually replaced by the more advanced
F-100 Super Sabre.
Notable achievements testing. • The F-84 was the first aircraft flown by the
U.S. Air Force Thunderbirds, which operated F‑84G Thunderjets from 1953 to 1955 and F-84F Thunderstreaks from 1955 to 1956. The F-84E was also flown by the team of
United States Air Forces Europe (USAFE). • On 7 September 1946, the second XP-84 prototype set a national speed record of 607.2 mph (527.6 kn, 977.2 km/h), slightly slower than the world record 612.2 mph (532.0 kn, 985.2 km/h) held by the British
Gloster Meteor. None of these records exceeded the April 1941 wartime achievement of an Me 163A rocket plane at some 624.2 mph; itself first exceeded by the American
Douglas D-558-1 Skystreak in August 1947, using basically the same Allison J35 turbojet engine as the F-84. • On 22 September 1950, two EF-84Es, flown by
David C. Schilling and Col. William Ritchie, refuelled using the
probe and drogue system from
Avro Lincoln tankers operated by the British company
Flight Refuelling Limited, flew across the
North Atlantic from Great Britain to the United States. Ritchie's aircraft ran out of fuel over
Newfoundland, but the other successfully made the crossing, which took 10 hours and 2 minutes and three aerial refuelings. The flight demonstrated that large numbers of fighters could be rapidly moved across the Atlantic. • The F-84G was the first fighter with built-in aerial refueling capability and the first single-seat aircraft capable of carrying a nuclear bomb. • On 20 August 1953, 17 F-84Gs of the
508th Strategic Fighter Wing using aerial refueling flew from the United States to the United Kingdom. The journey was the longest-ever nonstop flight by jet fighters at the time. • In 1955, an F-84G became the first aircraft to be
zero-length launched from a trailer.
Costs Notes:
The costs are 1950 estimates and have not been adjusted for inflation. ==Variants==