Click on Picture to enlarge

+ Larger Font | - Smaller Font

By Joe Baugher

ick on Picture to enlarge

The F-84F "Thunderstreak" was introduced in 1949, as a competitor to North American Aviation's F-86 "Sabre". The "F" model differs from the "C" model in that its wings are swept back 40 degrees; its tail and elevator are swept back and it has a smaller canopy and redesigned windscreen. First flown in November of 1952, it was built too late for the "F" model to see combat in Korea. Some "Thunderstreaks" did see combat while serving with England and France in the 1956 "Suez Crisis". The "Thunderstreak" was also produced as the RF-84F "Thunderflash". This version had an extended nose that was capable of carrying 6 cameras for use in the photo-reconnaissance role. The jet intake scoops were moved from the nose to the wing roots on the RF-84F model.

Click on Picture to enlarge

Although the F-84F Thunderstreak was a modified F-84E, it only utilized 15% of its ancestor's airframe. With the addition of swept wings and tail, and improved engines, the new aircraft matched anything flying in 1954. The F-84F became the front line fighter bomber of NATO throughout the 1950's. US Air National Guard F-84F's were deployed to Europe to provide close support during the Berlin Crisis of 1961. Turkey and Greece did not retire their F-84F's until the mid 1970's. A reconnaissance version of the aircraft, the RF-84F Thunderflash had a lengthened nose and modified air intakes, making it the first aircraft capable of night photography.

 

A swept-wing version of the F-84 had been planned late in 1949 in order to bring the performance of the Thunderjet up to the level of that of the F-86 Sabre. However, it was hoped that the swept wing version would retain or even improve the ground attack capabilities of the Thunderjet. At this time, USAF funds for new aircraft development were rather limited, and it was thought that by using some 60 percent of existing Thunderjet tooling and a standard F-84E fuselage, a high-performance aircraft could be produced at minimal cost.

The swept-wing version of the Thunderjet was initially designated XF-96A because of its extensive design changes. The USAF sanctioned construction of a single prototype. The last aircraft on the F-84E contract (49-2430) was selected for the conversion. The fuselage of the XF-96A was essentially that of the F-84E, including the pilot's rearward-sliding canopy and the air brake underneath the fuselage. The tail was swept back and an entirely new wing, swept back at an angle of 38.5 degrees was used. The new wing had an area of 325 square feet and a span of 36 feet 5 inches. The wing had its maximum thickness at 45 percent chord, although the chord-wise thickness ratio was only nine percent. The swept wing had an anhedral (negative dihedral) of 3.5 degrees. The engine was an Allison J35-A-25 of 5200 lb.st.

The construction of XF-96A 49-2430 took 167 days. It was then dismantled and flown from Farmingdale via cargo aircraft out to Muroc. It was reassembled there and took off on its maiden flight on June 3, 1950, piloted by Republic's Director of Flight Otto P. Haas. Performance included a maximum speed of 693 mph at sea level (Mach 0.93), and a range of 1716 miles at a cruising speed of 514 mph. Maximum fuel load was 1253 Imp. gall internally and externally, and the empty and maximum loaded weights were 12,150 pounds and 23,350 pounds respectively. Although the low-altitude speed was impressive, performance fell off rather badly with altitude. Service ceiling was only 38,300 feet and it took 14.8 minutes to reach an altitude of 35,000 feet. It was felt that the performance improvement over the F-84E was only marginal at best, and the project proceeded with only low priority.

Were it not for the Korean War, the XF-96A project probably would have been cancelled. As it turned out, the onset of the Korean War freed up some USAF funds for continued development and a letter contract for F-96A production was received in July of 1950. On August 9, 1950, the designation was changed to XF-84F, and the name Thunderstreak was chosen. It was anticipated that the first production Thunderstreaks would be available in the autumn of 1951.

 

 

The Republic YF-84

 

Even though the low-level performance of the XF-84F was good, the USAF felt that more power was badly needed to improve a relatively sluggish takeoff, climb, and high-altitude performance. For this purpose, the British-designed Armstrong-Siddeley Sapphire axial-flow turbojet of 7200 lb.st. was selected, and arrangements were made to have the Sapphire engine produced under license in the USA by Curtiss-Wright as the J65.

The Sapphire engine was considerably larger than the J35, which required that the fuselage of the XF-84F be extensively redesigned in order to accommodate it. The depth of the fuselage was increased by seven inches, and the nose intake was enlarged to an elliptical shape. The first prototype XF-84F (49-2430) was reengined with an imported Sapphire, and flew for the first time with this engine on February 14, 1951.

Two pre-production YF-84F aircraft (51-1344 and 51-1345) with Sapphire engines were built by Republic in 1951. The second example (51-1345) was completed with wing root air intakes, leaving the nose with a solid cover. The wing root intakes resulted in thrust losses as compared to the nose intake version, and were not adopted for production fighters.

 

 

The Republic F-84F

 

The original production schedule for the Thunderstreak that was prepared in August of 1950 called for the first deliveries to be made by the autumn of 1951. The production F-84Fs were to use heavy press forgings in the construction of the wing structure. However, the only forge press in the country suitable for the job was tied up in the B-47 program. A mechanical breakdown in the press caused further delays. To make matters worse, serious delays were encountered in the production of the J65 license-built Sapphire engines. In July of 1951, Republic was forced to admit to the USAF that the original schedule could not be met.

In order to get the F-84F program back on track, it was decided to redesign the wings so that they could be manufactured with existing tools and facilities. Although this would cure the press forgings problem, this redesign would add many months to the delivery schedule. In order to fill in the production gap until the F-84F could be available, the USAF decided to have Republic built the straight-winged F-84G as a stop-gap measure. The delays in the Thunderstreak program were in fact so time-consuming that the F-84G actually became the most widely-produced F-84 version produced, some 3025 examples being built before the last one rolled off the production lines on July 27, 1953.

The first production F-84F-1-RE (51-1346) was finally ready for its first flight in the late fall of 1952. It took off on its maiden flight on November 22, 1952. The production F-84F differed in several important respects from the earlier service test models. The cockpit canopy had previously been a sliding bubble type similar to that fitted to "straight-wing" F-84s. The cockpit canopy was now of a hinged arm, upward-swinging type that raised the part of the enclosure upward above the pilot before it swung backwards. For normal exits, the canopy was pushed upward, but for emergencies the canopy could be completely released from the aircraft to permit pilot ejection. This canopy was stronger, easier to install, and better sealed than the sliding version.

The production F-84F also introduced a raised "turtle deck" aft of the cockpit, which replaced the rear fuselage deck of the previous bubble-canopied versions.

Service-test Thunderstreak models had a single speed brake on the belly of the fuselage, similiar to that of the Thunderjet. The production Thunderstreak replaced this with two perforated panels on the fuselage sides just aft of the wing trailing edge. These brakes could be opened at any speed up to the maximum dive speed without large trim changes or excessive buffeting.

Leading edge wing slats were added to improve airflow characteristics. Control tabs were removed from the ailerons in favor of an irreversible power-boosted control system.

Production of the Thunderstreak at Farmingdale was supplemented by subcontractors such as Kaiser Metal Products of Bristol, Pennsylvania which built the rear fuselage, Servel of Evansville, Indiana which built wings, and Goodyear Aircraft which built the cockpit windshield, canopy, and rear fuselage turtle deck.

A second source of Thunderstreak production was established in 1952 when a contract was given to General Motors to build Thunderstreaks in a plant at Kansas City. This plant had been used by North American Aviation during World War II to build B-25 Mitchells. General Motors-built Thunderstreaks were known as F-84F-GK (rather than RE), and could be distinguished from Republic-built Thunderstreaks only by their serial numbers.

Ten examples of the F-84F-1-RE were built. They were powered with the early US-built Wright J65-W-1 turbojet.

The F-84F-5-RE had the 7330 lb.st. J65-W-3 or the equivalent Buick-built J65-B-3. The deliveries of this version began in the latter part of 1953. The first F-84F-25-RE (51-1621) appeared at the end of 1953. It introduced an "all-flying" horizontal tailplane, in which the entire horizontal tail moved as a unit. The earlier F-84Fs suffered from a high-g stall pitch-up tendency which was often severe enough to tear the wings off the aircraft. This could make for a real bad day :-). The all-flying tail provided more positive control which helped to alleviate this problem, although the F-84F continued to operate under maneuverability restrictions throughout much of its service life.

The F-84F-50-RE appeared in March of 1955. It had the more powerful J65-W-7 (or J65-B-7), rated at 7800 lb.st. Airframe limitations prevented any improvements in low-altitude speed, but the added power increased the initial climb rate and the combat ceiling.

The F-84F-75-RE was the last version of the Thunderstreak to be built at Farmingdale. It introduced a new fairing under the fuselage for the braking parachute. This feature was later retrofitted to earlier models.

The last Thunderstreak rolled off the production lines at Farmingdale in August of 1957. A total of 2112 examples had been built. An additional 599 had been built by General Motors.

F-84F serial numbers:

51-1344/1345 	Republic YF-84F-RE Thunderstreak 
51-1346/1355 	Republic F-84F-1-RE Thunderstreak 
51-1356/1380 	Republic F-84F-5-RE Thunderstreak 
51-1381/1430 	Republic F-84F-10-RE Thunderstreak 
51-1431/1510 	Republic F-84F-15-RE Thunderstreak 
51-1511/1620 	Republic F-84F-20-RE Thunderstreak 
51-1621/1709 	Republic F-84F-25-RE Thunderstreak 
51-1710/1760 	Republic F-84F-25-RE Thunderstreak 
51-1761/1827 	Republic F-84F-30-RE Thunderstreak 
51-9311/9320 	General Motors F-84F-1-GK Thunderstreak 
51-9321/9335 	General Motors F-84F-5-GK Thunderstreak 
51-9336/9356 	General Motors F-84F-10-GK Thunderstreak 
51-9357/9409 	General Motors F-84F-25-GK Thunderstreak 
51-9410/9454 	General Motors F-84F-30-GK Thunderstreak 
51-9455/9503 	General Motors F-84F-35-GK Thunderstreak 
51-9504/9547 	General Motors F-84F-40-GK Thunderstreak 
51-17061/17088 	Republic F-84F-35-RE Thunderstreak 
52-6355/6422 	Republic F-84F-30-RE Thunderstreak 
52-6423/6522 	Republic F-84F-35-RE Thunderstreak 
52-6523/6642 	Republic F-84F-40-RE Thunderstreak 
52-6643/6812 	Republic F-84F-45-RE Thunderstreak 
52-6813/6907 	Republic F-84F-50-RE Thunderstreak 
52-6908/7007 	Republic F-84F-55-RE Thunderstreak 
52-7008/7017 	Republic F-84F-56-RE Thunderstreak 
52-7018/7049 	Republic F-84F-35-RE Thunderstreak 
52-7050/7089 	Republic F-84F-40-RE Thunderstreak 
52-7090/7114 	Republic F-84F-45-RE Thunderstreak 
52-7115/7126 	Republic F-84F-46-RE Thunderstreak 
52-7127/7191 	Republic F-84F-51-RE Thunderstreak 
52-7192/7228 	Republic F-84F-56-RE Thunderstreak 
52-8767/8834 	General Motors F-84F-41-GK Thunderstreak 
52-8835/8982 	General Motors F-84F-46-GK Thunderstreak 
52-8983/9128 	General Motors F-84F-51-GK Thunderstreak 
52-10510/10538 	Republic F-84F-56-RE Thunderstreak 
53-6532/6715 	Republic F-84F-61-RE Thunderstreak 
53-6716/6835 	Republic F-84F-66-RE Thunderstreak 
53-6836/6955 	Republic F-84F-71-RE Thunderstreak 
53-6956/7075 	Republic F-84F-76-RE Thunderstreak 
53-7076/7230 	Republic F-84F-81-RE Thunderstreak 
53-7231/7520 	Cancelled contract for F-84F 

Specification of the F-84F-25-RE:

One Wright J65-W-3 turbojet rated at 7220 lb.st. Maximum speed (clean), 695 mph at sea level (Mach 0.91), 658 mph at 20,000 feet (Mach 0.94) The F-84F is redlined at Mach 1.18 in a dive. Tactical radial (clean): 450 miles at 36,000 feet. Combat radius with two 230 US gallon drop tanks is 790 miles. Ferry range with four 230 US gallon drop tanks is 2140 miles. Initial climb rate (clean): 8200 feet per minute. Service ceiling: 46,000 feet. Weights: 14,014 pounds empty, 19,340 pounds combat weight (clean), normal loaded 26,000 pounds, and 28,000 pounds maximum takeoff. Dimensions: wingspan 33 feet 7 1/4 inches, length 43 feet 4 3/4 inches, height 14 feet 4 3/4 inches, wing area 325 square feet. Armament consisted of six 0.50-inch M-3 machine guns, four mounted in the nose and two mounted in the wing roots. A radar-ranging A-4 gunsight was provided. A maximum of 6000 pounds of external ordinance could be carried, a typical load being two 2000-lb. bombs and eight 5-inch HVARs or four 1000-pound bombs and 24 3-inch rockets. Total internal fuel capacity was 475 Imp.gall., but two 191.5 Imp.gall. drop tanks are normally carried on the inner underwing racks, while for ferry purposes two 375 Imp. gall or four 191.5 Imp.gall drop tanks could be carried to provide a range of 2140 miles.

 

 

The F-84F In Service with The USAF

 

The USAF had the F-84F in service with twelve Wings by June of 1955. Six of them were attached to the Tactical Air Command (TAC) and six to the Strategic Air Command (SAC).

The F-84Fs serving with the TAC were equipped for the delivery of nuclear weapons. The nuclear bomb-toting Thunderstreaks were equipped with the Low Altitude Bombing System (LABS). When using the LABS to deliver a nuclear bomb, the strategy was for the F-84F to come racing toward the target at tree-top level. When nearing the target, the F-84F was to make a half loop upward, release its bomb, and then escape the nuclear blast with a rapid high-speed Immelmann to head back where it came from. Fortunately, the Thunderstreak was never called upon to carry out such missions in real combat.

The Thunderstreak-equipped USAF wings attached to the Strategic Air Command served as fighter escorts for B-29, B-50, and B-36 long-range strategic bombers. As these bombers were replaced by jets, SAC relinquished its F-84Fs and turned them over to the Tactical Air Command. By mid-1957, all the USAF Thunderstreaks had been shifted over to the TAC.

The Thunderstreak was flown by the following Fighter Bomber Groups of the USAF:

• 20th Fighter Bomber Group
   
• 31st Fighter Bomber Group
   
• 405th Fighter Bomber Group (509th, 510th, 511th Squadrons), Langley AFB
   
• 407th Fighter Bomber Group (515th, 516th, 517th Squadrons)
   
• 506th Strategic Fighter Wing (457th, 458th, 463rd Strategic Fighter Squadrons). Based at Dow AFB, Maine in early 1950s and moved to Tinker AFB, Oklahoma in 1955.
   
• 366th Fighter Bomber Group (389th, 390th, 391st Squadrons)
   
• 81st Fighter Bomber Group (78th, 91st, 92nd Squadrons)
   
• 15th Fighter Bomber Group (45th, 46th, 47th Squadrons)
   
• 21st Fighter Bomber Group (416th Squadron)

The pilots of the TAC and SAC found the F-84F to be a rather difficult plane to fly. Its loaded weight of 20,000 pounds and its landing speed of 155 mph made it a rather "hot" ship for pilots who were more familiar to lighter and slower-landing machines, and it took a bit of getting used to. In addition, the handling properties of the F-84F were somewhat tricky, and certain maneuvers were deemed too dangerous to perform except in extreme emergencies. Nevertheless, the F-84F achieved a reputation for being of extremely robust construction and of high reliability, and it offered a relatively smooth ride through turbulent low-level air.

Gradually, the F-84F was replaced in front-line service by the North American F-100 Super Sabre. Numerous F-84Fs were turned over to Air National Guard units as they were withdrawn from USAF units. However, the Berlin Crisis of 1961 saw the recall of numerous F-84Fs to active duty--the 141st Tactical Fighter Squadron from McGuire AFB, the 163rd TFS from Fort Wayne, Indiana, and the 166th TFS from Columbus, Ohio were Air National Guard units that were deployed to Europe in response to the crisis. The F-84F remained with TAC until the mid 1960s, when they were replaced by McDonnell F-4C Phantoms. The F-84Fs with the Air National Guard were finally phased out in the late 1960s. The last F-84F left ANG service in 1971.

 

 

The F-84F In service With NATO Forces

The F-84F was supplied in large numbers to NATO air forces. In fact, out of the 2711 Thunderstreaks built, 1301 were transferred to Europe for service with the air forces of allied nations.
 

France

First to get Thunderstreaks was France. The Armee de l'Air received its first Thunderstreaks in 1955. They equipped the the 1st, 3rd, 4th, 6th, and 11 th Escadres. It was in French service that the Thunderstreak saw its only actual combat. This was during the Suez incident of October of 1956. On October 23, 1956, 36 French Thunderstreaks from the 1st Escadre flew to the Israeli base at Lyddia and at the same time F-84Fs from the 3rd Escadre moved to Akrotiri on Cyprus. The French Thunderstreaks at Lydda supported the Israeli forces that invaded Sinai on October 29. Cyprus-based units began direct attacks on Egyptian airfields on November 1. Twenty Egyptian Ilyushin Il-28 bombers were destroyed on the ground and one Il-28 was shot down by these Lydda-based units. These operations were concluded on November 6, and only one F-84F was lost. The French F-84Fs were replaced by Mirage IIIE in the mid 1960s.
 

Belgium

Belgium's Force Aerienne Belge began receiving F-84Fs in August of 1955. They replaced the F-84G Thunderjets of the 2nd and 10th Fighter Bomber wings. Most of the Belgian F-84Fs were replaced by F-104G Starfighters during the early 1960s.
 

Netherlands

The six tactical fighter bomber squadrons of Holland's Koninklijke Nederlandse Luchtmacht (Nos. 311 through 316) standardized on the F-84F in 1956. They were replaced by F-104G Starfighters during the early 1960s.
 

Italy

The Aeronautica Militare Italiano equipped three Air Brigades (Aerobrigata 5a, 51, and 51a) with F-84Fs in 1956.
 

West Germany

The newly-revived West German Luftwaffe received large numbers of F-84Fs. The Thunderstreak was in fact the first combat aircraft to be operated by the new Luftwaffe after the end of World War II. On June 20, 1958, the first German fighter-bomber wing, Jabo G.31, became operational. Four more, Jabo G.32, 34, and 35, were soon added. Some 450 Thunderstreaks served with the Luftwaffe during the late 1950s and early 1960s. The Thunderstreak was eventually replaced in Luftwaffe service by the European-built F-104G Starfighter.
 

Greece and Turkey

Some of the ex-German, Belgian, and Dutch Thunderstreaks were transferred to Greece and Turkey. It seems that every time a combat aircraft is transferred to Greece, one must also be transferred to Turkey, and vice versa. :-). Some of these Thunderstreaks remained operational into the late 1970s until they were finally replaced by Northrop F-5s. F-84Fs were employed by Turkey in the fighting over Cyprus during the 1970s, but I have no record of Greek and Turkish Thunderstreaks ever facing each other in combat.

BY JOE BAUGER

Sources:

1. Fighters of the United States Air Force, Robert F. Dorr and David Donald, Temple Press Aerospace, 1990.
    
2. The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.
    
3. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.
    
4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
    
5. The Republic F-84F Thunderstreak, Ray Wagner, Profile Publications, 1966.
    
6. E-mail from Don Runyon on 506th Strategic Fighter Wing.

 

THE F-84	The F-84E /G
More About THE F-84F	The Thunderbirds & The F-84F
The Thunderbirds & The F-84G	The RF-84F Recon
YRF-84F FICOM	The XF-84H

 

USE YOUR BROWSER "BACK" BUTTON TO RETURN TO PERVIOUS PAGE