In 1944, the Republic Aviation Company is envisaging to give a successor to the famous P-47 Thunderboldt. The first project is to transform the Thunderboldt into a jet fighter, but soon the project will be replaced by the conception of a brand new fighter based on the General Electric TG-180 reactor: the Thunderjet.

In march 1945 the US Army place an order for three prototypes and 400 serie aircrafts; this order will be modified later in 15 pre-serie YP-84A aircrafts and 85 production aircrafts P-84B.

Republic F-84 family

Republic F-84 family

The first flight of the YP-84A was made on 28 February 1946. Two other prototypes will follow and then the 15 pre-serie aircrafts, since April 1947. Some months later the delivery of the P-84B will begin.

In may 1948 appears the P-84C with a new, more powerful engine and six months later the P-84D with minor modifications. 550 aircrafts will be delivered.

But the engine is not so powerful as expected; the F-80 Shooting Star remains better than the P-84… More than 100 modifications will be needed to ameliorate the aircrafts, that evolved in may 1949 into a new version: the F-84E.

The F-84E haves a more powerful engine ; a radar for shooting ; the structure is reinforced and the fuselage is lengthened to give a more bigger space for the cockpit. But the shooting system lacks of friability and that results in longer delays of delivery.

The Thunderjet will know a last evolution: the F-84G. Conceived as a fighter-bomber, he was able to have a load of 1814kg and eventually an atomic bomb. The engine is more powerful and the aircraft can be re fuelled in flight. The canopy is also reinforced. And lastly, there is an automatic pilot. The deliveries will begin since June 1951 ; about 3000 F-84G were built from which 2/3 were distributed to the NATO air forces (Military Assistance Program): the different nations received the aircrafts as a loan; had to give them back to the USA in pristine state and to pay for all aircrafts destructed.

The different air forces that used that aircraft are:

–          USA
–          France
–          Germany
–          The Netherlands
–          Norway
–          Denmark
–          Portugal
–          Italy
–          Greece
–          Turkey
–          Yugoslavia
–          Thailand
–          Taiwan

For those nations, the capabilities of nuclear bomb transport were removed.

The Thunderjet participated in the Korean War. It was really successful in ground support missions, but fighter missions flown to escort B-29 revealed that it was too slow to match the famous MiG-15…

But since 1949 the possibility to make a version of the Thunderjet with swept wings is envisaged: that will become the F-84F Thunderstreak. The goal was to raise the speed of the Thunderjet while retaining, and even increasing, his superior ground attack capabilities. The last and 409th aircraft of the F-84E contract became the YF-84 prototype for the swept wings.

On 3 June 1950 the aircraft had his maiden flight. At that time it was designed YF-96A due to his extensive changes compared to the F-84E. But on 9august the designation reverted back to YF-84…

The maximum speed at sea level increases of 120 km/h but the performances in altitude are not really better. The aircraft needs of a more powerful engine to be ameliorated. The engine chosen is the British Sapphire but to introduce it in the aircraft, it is needed to enlarge the fuselage.

Two prototypes are build in 1951: one with the well known air admission in the fuselage, the second one with a nose but two air admissions in the wings (like it will be made for the Thunderflash). But the second version reveals some air admission problems and is abandoned.

Unfortunately the program will suffer a delay of two years, due to a series of problems : not enough hydraulic presses to fabricate the swept wings ; the engine is knowing many problems ; the flight controls are in adapted at high speed ; plus other problems… Mid-1954 will see all but the engine problems solved. Those engine problems will cause the loss of numerous aircrafts

It must be said that it’s due to the delay of two years in the Thunderstreak program that the F-84G version of the Thunderjet was developed… Initially, the Thunderstreak was conceived to have at least 50% of common components with the Thunderjet. But finally, there were only 15%. All the tests made proved that the Thunderstreak was from far superior to the Thunderjet.

Again, a majority of the production the Thunderstreaks was distributed to the NATO nations.

France received his Thunderstreaks in 1955. In 1956, the Suez Crisis gives the opportunity to see the F-84F in combat action: France and England collaborated with Israel against Egypt. 36 French Thunderstreak participated in the Operation Musketeer. There were based on Isreal’s Lydda air base and flew with yellow and black stripes on the wings for recognition purposes. There were little opposition of the Egyptian air force; the French aircrafts destroyed many Egyptian bombers on the ground for the loss of one aircraft and his pilot only.

Belgium received his Thunderstreak from August 1955, and by the following year all their Thunderjets were replaced. The Netherlands followed in 1956. It was also the case for Germany since November 1956 that equipped the newly reborn Luftwaffe. Later those aircrafts will be replaced by F-104G Starfighters and ceded to Greece and Turkey. It is also interesting to note that Belgium kept some Thunderstreaks when there were replaced by the Mirage V, using them as decoys on Florennes air base: the wings were modified to become similar to those of the Mirage (wings were made in wood) and a cone was placed on the nose of the aircrafts…

As said above in the text, there were two prototypes conceived for the Thunderstreak, the second one having two air admissions in the wings. If that was a problem for the fighter-bomber version, it offered on the other hand excellent perspectives to place cameras in the nose, and so to obtain an excellent reconnaissance fighter! That was the start for the RF-84F Thunderflash. The formula used gives the possibility to place 6 cameras in the nose of the aircraft; a periscope for the pilot to see the filmed zones and an electronic system for the cameras based on the speed and altitude.

Of course the Thunderflash will be victim of the same problems than the Thunderstreak, and the production will also be delayed until 1955. During the production, a more powerful engine will be used.

Like for the other members of the “Thunder” family, the majority of the aircrafts were dispatched to the NATO air forces.

Finally, there were some variants and projects that are listed here:

  • XP-84A Thunderjet – prototypes (2 ex.)
  • YP-84A Thunderjet – pre-serie version (15 ex.)
  • P-84B/F-84B Thunderjet – first version in production (226 ex.)
  • P-84C/F-84C Thunderjet – Engine and electric system modified (191 ex.)
  • P-84D/F-84D Thunderjet – more powerful engine (151 ex.)
  • F-84E Thunderjet – (843 ex.)
  • F-84F Thunderstreak – swept wings, more powerful engine (2711 ex.)
  • RF-84F Thunderflash – recce version of the F-84F (715 ex.)
  • F-84G Thunderjet – more powerful engine, automatic pilot, nuclear (3025 ex.)
  • RF-84K Thunderflash – RF-84F modified to be fixed under a RB-36 (25 modified aircrafts)

 Nico Braas