Republic F-84 Thunderjet
First production fighter with inflight refueling and nuclear capability.
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The Republic F-84 Thunderjet was an American turbojet fighter-bomber. It began as a 1944 U.S. Army Air Forces request for a day fighter, first flew in 1946, and entered service the following year.
Operational history
Despite this, early models were so plagued by structural and engine failures that a 1948 Air Force review found the aircraft unable to perform any of its intended missions, nearly leading to cancellation. The design only became fully operational with the F-84D in 1949, and the definitive F-84G arrived in 1951. In 1954, the straight-wing Thunderjet was joined by the swept-wing F-84F Thunderstreak and the RF-84F Thunderflash reconnaissance variant.
During the Korean War, the Thunderjet served as the USAF’s primary strike aircraft, flying 86,408 sorties. It destroyed 60% of all ground targets in the conflict and shot down eight Soviet-built MiG fighters. Over half of the 7,524 F-84s built went to NATO nations. The aircraft also flew with the U.S. Air Force Thunderbirds demonstration team and served in Strategic Air Command from 1948 to 1957.
The F-84 was the first production fighter to use inflight refueling and the first capable of carrying a nuclear weapon, the Mark 7 bomb. Modified versions took part in unusual projects like the FICON and Tom-Tom docking experiments with B-29 and B-36 bombers, and the experimental XF-84H Thunderscreech turboprop.
Naming can be confusing. Straight-wing models from the F-84A through F-84E and F-84G were called Thunderjets. The swept-wing F-84F Thunderstreak and RF-84F Thunderflash were different aircraft.
The XF-84H Thunderscreech was an experimental turboprop based on the F-84F. The swept-wing F-84F was originally intended as a minor variation of the Thunderjet, so it kept the F-84 designation. Production delays on the F-84F led to an additional order of straight-wing versions, which became the F-84G.
Design and development
In 1944, Republic Aviation’s chief designer Alexander Kartveli began work on a jet-powered replacement for the P-47 Thunderbolt. Early attempts to modify the P-47 failed because of its wide fuselage. Instead, Kartveli’s team designed a slimmer fuselage with a rear-mounted axial turbojet and a nose intake, with air ducts taking up much of the interior volume. Fuel was stored mainly in the thick, unswept wings, which used a laminar flow airfoil.
Lore & Background
The Thunderjet was designed by Republic Aviation's chief designer Alexander Kartveli as a turbojet replacement for the P-47 Thunderbolt. The initial attempts to redesign the P-47 proved futile due to the large cross-section of the Thunderbolt's fuselage, leading to a new design with a slimmer fuselage housing an axial compressor turbojet engine in the rear and an air intake in the nose.
Fuel was mainly stored in tanks in the thick, laminar flow airfoil, unswept wings. The USAAF released General Operational Requirements on 11 September 1944 for a day fighter with a top speed of 600 mph, a combat radius of 850 mi, and armament of either eight .50 in or six .60 in machine guns, though these specifications proved too ambitious and were later reduced. Republic received an order for three prototypes on 11 November 1944, and the name 'Thunderjet' was chosen to continue the Republic tradition started with the P-47 Thunderbolt while emphasizing the new propulsion method.
The first prototype XP-84 flew on 28 February 1946 at Muroc Army Air Field with Major Wallace A. 'Wally' Lien at the controls. On 8 September 1946, the second XP-84 set a US national airspeed record of 607.2 mph.
The Thunderjet was plagued by structural and engine problems; a 1948 U.S. Air Force review declared it unable to execute any aspect of its intended mission and considered canceling the program. The aircraft was not considered fully operational until the 1949 F-84D model, and the design matured with the definitive F-84G introduced in 1951. In 1954, the straight-wing Thunderjet was joined by the swept-wing F-84F Thunderstreak and RF-84F Thunderflash photo reconnaissance aircraft.
Reader's Guide
The F-84 Thunderjet's significance lies in its role as the USAF's primary strike aircraft during the Korean War, where it flew 86,408 sorties and destroyed 60% of all ground targets in the war as well as eight Soviet-built MiG fighters. Over half of the 7,524 F-84s produced served with NATO nations, and it was the first aircraft to fly with the U.S. Air Force Thunderbirds demonstration team. The USAF Strategic Air Command had F-84 Thunderjets in service from 1948 through 1957. The F-84 was the first production fighter aircraft to utilize inflight refueling and the first fighter capable of carrying a nuclear weapon, the Mark 7 nuclear bomb.
Modified F-84s were used in several unusual projects, including the FICON and Tom-Tom dockings to the B-29 Superfortress and B-36 bomber motherships, and the experimental XF-84H Thunderscreech turboprop. The F-84 nomenclature can be confusing: the straight-wing F-84A to F-84E and F-84G models were called the Thunderjet, while the F-84F Thunderstreak and RF-84F Thunderflash were different airplanes with swept wings. The XF-84H Thunderscreech was an experimental turboprop version of the F-84F. Production delays on the F-84F resulted in another order of the straight-wing version, the F-84G.
Frequently Asked Questions
Why was the F-84 Thunderjet nearly cancelled in 1948?
Early production models were riddled with structural weaknesses and unreliable engines, leading a 1948 Air Force review to declare the aircraft incapable of performing any of its assigned missions. The type only became genuinely mission-capable once the redesigned F-84D variant entered service in 1949.
What firsts did the F-84 Thunderjet achieve?
It was the first production fighter aircraft to combine inflight refueling capability with the ability to deliver nuclear weapons. Those two features together made it a cornerstone of early Cold War air power.
What engine and armament did the F-84 Thunderjet carry?
The Thunderjet was powered by an Allison J35 axial-flow turbojet engine. Its fixed guns consisted of six .50-caliber M2 or M3 machine guns mounted in the wings.
How did the F-84 Thunderjet evolve across its production life?
The straight-wing F-84G, introduced in 1951, became the definitive and most widely fielded variant of the family. In 1954 the swept-wing F-84F Thunderstreak entered the lineup, signaling the shift toward the next generation of jet fighters.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Republic F-84 Thunderjet (CC BY-SA 4.0).
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