| F9F/F-9 Cougar | |
|---|---|
 Grumman F9F-6 Cougar, 1952 | |
| General information | |
| Type | Fighter aircraft |
| National origin | United States |
| Manufacturer | Grumman |
| Status | Retired |
| Primary users | United States Navy |
| Number built | 1,988[1] |
| History | |
| Introduction date | December 1952 |
| First flight | 20 September 1951 |
| Retired | 1974 (US Navy) |
| Developed from | Grumman F9F Panther |
TheGrumman F9F/F-9 Cougar is acarrier-basedjet-poweredfighter aircraft designed and produced by the American aircraft manufacturerGrumman.
It was developed during the early 1950s on behalf of theUnited States Navy (US Navy) andUnited States Marine Corps (USMC), which were keen to quickly introduce a naval fighter equipped with aswept wing. Grumman's design team decided to adapt its earlierF9F Panther, replacing the straight wing of the Panther with a new swept wing. Thrust was also increased with the installation of a newer and more powerful engine. Nevertheless, the aircraft remained limited to subsonic speeds. The first prototype (XF9F-6), which was produced by modifying an existing Panther, performed itsmaiden flight on 20 September 1951. The Navy considered the Cougar to be an updated version of the Panther, despite having a different official name, and thus Cougars started off fromF9F-6.
During December 1952, the F9F-6 was introduced to service,VF-32 being the first squadron to receive the type; while developed at a relatively rapid pace, the Cougar's arrival was too late for it to engage in active combat during theKorean War. While initial production aircraft were powered by a singlePratt & Whitney J48turbojet engine, theF9F-7 were furnished by anAllison J33 powerplant instead. In the mid 1950s, the improvedF9F-8 was introduced, which had a lowerstall speed, improved handling when flown at highangles of attack, and increased range. The twin-seatF9F-8T was procured by the US Navy to perform various forms of training. TheF9F-8Pphoto-reconnaissance variant was created by converting existing F9F-8s; most of the modifications were made to the aircraft's nose.
On 1 April 1954, US Navy Cougars established a new transcontinental crossing record. The US Navy's flight demonstration team, theBlue Angels, adopted the type in place of its Panthers. The Cougar gained a favourable reputation as a highly maneuverable and easy to fly aircraft. The only foreign air service that operated the Cougar was theArgentine Naval Aviation. The F9F-8 was withdrawn from front-line duties during the late 1950s, having been replaced by more capable aircraft such as theF11F Tigers andF8U Crusaders. While the Naval Reserves flew Cougars into the mid-1960s, only the TF-9J trainer model saw actual combat, having been deployed as aForward Air Control aircraft during theVietnam War. Following its withdrawal from active service, many F9F-6s were used as unmanned drones for combat training, designatedF9F-6D, or as drone controllers, designatedF9F-6K.
Rumors that theSoviet Union had produced a swept wing fighter had circulated a year before theMikoyan-Gurevich MiG-15 first appeared at air shows in 1949. Despite the level of activity taking place with swept wing aircraft, the US Navy was not initially focused on the development of such aircraft. This was largely because the US Navy's focus at the time was defending the battle group against high speed, high altitude bombers with interceptors, as well as escorting medium-range carrier-based bombers in all weather conditions; air-to-air combat was of less interest at that time. Nonetheless, the US Navy appreciated the importance of getting a capable carrier-based swept wing jet fighter. Grumman was awarded a contract for the development of a swept-wing fighter jet in early 1951. The arrival of the MiG-15, which easily outclassed straight-wing fighters in the air war over North Korea, was a major factor.[2][3][4]
Development proceeded at a relatively rapid pace, in part due to Grumman's pre-existing experience of studying prospective derivatives of the Panther guiding several of their design choices.[5] One example of this was the design team's decision to retain the center fuselage section of the Panther relatively unchanged, as studies of various alternative arrangements had been determined to have introducedcenter of gravity issues that in turn would have compelled substantial redesigns of other elements of the aircraft, including its propulsion. Instead, the aircraft shared the Panther's engine,landing gear, and various other systems.[5] By changing as little as possible, the company was able to produce a swept wing fighter for the US Navy in mere months, rather than the years involved in delivering a clean-sheet design.[5]
However, it was necessary to implement various design changes. To effectively accommodate the switch from a straight wing to a swept one, it was necessary to delete the two 120-gallontip tanks, as in combination with the swept wing there would have been too great a negative impact upon the aircraft's center of gravity; for the same reason, only a singlehardpoint was fitted under each wing.[5] Instead, internal fuel tanks housed within the wing were adopted, although these had less capacity than the tip tanks had. Theleading edgeflaps present on the Panther were deleted in favour of aslats, while thetrailing edge slats and fuselage-mounted flaps were both redesigned to be effective with the swept wing.[5] The modified fuselage flaps could also function as a second set ofair brakes.[5]
ThreeXF9F-6 prototypes, two airworthy and one static test airframe, were rapidly produced by modifying existing Panthers straight off the production line.[5] On 20 September 1951, the first prototype conducted itsmaiden flight, piloted by Grumman test pilot Fred Rowley, only six months following the contract's awarding. Few meaningful problems were encountered during flight testing, most being quickly resolved or accepted on the basis of the perceived urgency for such an aircraft to be made available.[5] The Cougar proved itself to be a definitive step forward; some pilots claimed the type to have superior handling at approach speeds than the preceding Panther.[6] In a full-power vertical dive, it could break thesound barrier without experiencing buffeting or major undesirable flight characteristics.[7] In level flight, the aircraft remained only capable ofsubsonic flight, however, thecritical Mach number was increased from 0.79 to 0.86 at sea level, and to 0.895 at 35,000 ft (10,000 m), thus delivering performance markedly superior to that of its predecessor.[8]
However, bothroll andpitch control were deemed to not satisfy the requirements. The original roll control arrangement, a combination of unboostedailerons andhydraulically-actuatedspoilers (referred to as "flaperons"), were insufficient when operated via mechanical linkage alone without hydraulic pressure, thus were redesigned.[9]Wing fences were added and the spoilers extended from the fences to the tips of the wing,[8] while the flaperons were divided into two halves, the inbound set being powered by a separate hydraulic system.[9]
Pitch control was initially achieved via a conventionalelevator andhorizontal stabilizer, therudder pedals controlled the section of the rudder beneath the horizontal tail surface, while the upper portion of the rudder was controlled by ayaw damper.[9][8] However, this arrangement was unsuited to high speed flight, thus a powered "flying tail" was adopted.[9] As such, the Cougar was capable of flying safely and easily even without the upper portion of the tail being present.[8]
The initial production model was theF9F-6; a total of 646 airframes were delivered between mid-1952 and July 1954. The F9F-6 first flew on 20 September 1951, seven months after Grumman signed a contract with the Navy for swept-wing fighter.[10] The first 30 production aircraft used the same J42 P-6 engine used in the F9F-5, but was then replaced by the more powerful J42 P-8 with 7,250 lbf (32.2 kN) of thrust.[11] The J42 was alicensed version of theRolls-Royce Nene.[12]
Armament was four 20 mm (.79 in) AN/M3 cannons in the nose and provisions for two 1,000 lb (450 kg) bombs or 150 US gal (570 L) drop tanks under the wings. Most were fitted with a UHF homing antenna under the nose, and some were fitted with probes forinflight refuelling. The F9F-6 used an Aero 5D-1 weapons sight with an APG-30A gun-ranging radar.[13] The F9F-6 was later designatedF-9F in 1962. Sixty were built asF9F-6P reconnaissance aircraft with cameras instead of the nose cannon.[14]
After withdrawal from active service, many F9F-6s were used as unmanned drones for combat training, designatedF9F-6D, or as drone controllers, designatedF9F-6K.[10] The F9F-6K and the F9F-6D were redesignated theQF-9F andDF-9F, respectively.
TheF9F-7 referred to the next batch of Cougars that were given theAllison J33 also found in the F9F-4, instead of thePratt & Whitney J48. A total of 168 were built, but the J33 proved both less powerful and less reliable than the J48. Almost all were retrofitted with the J48 engine, and were thus indistinguishable from F9F-6s.[7] These were redesignatedF-9H in 1962.[15][16][17]
The Navy used two modified F9F-7s to conduct experiments landing on British-inspiredflexible decks which did not require the use of landing gear. The reasoning was that since an airplane's landing gear comprises some 33% of the total weight, a plane without landing gear would gain a greater range and would be able to carry more ordnance.[17] The aircraft were fitted with a 3-inch-deep (76 mm) false bottom under the center fuselage to help balance the plane during landings on the flex-deck made up of a lubricated rubberized fabric. The deck, built byGoodyear was1⁄2 inch (13 mm) thick and featured several arresting cables.[18] The planes were launched using a ramp and a handling dolly which served as temporary landing gear.[19] The two F9F-7 aircraft in the test were equipped with the powerful J48-P8 engine instead of the Allison J33 engine originally used with the F9F-7. While the landing tests yielded positive results and proved that landing was clearly possible, the project was terminated in 1955 as it would have been difficult to move the aircraft around the carrier deck once they landed. It also required a highly skilled pilot to perform the landings and would have made it impossible to divert to a land base if necessary.[18][20]
Work on the F9F-8 began in April 1953 with three goals: lower the airplane's stall speed, improve aircraft control at high angles of attack, and increase range. It featured an 8 in (20 cm) stretch in the fuselage and modified wings with a greater chord, an increased area (from 300 to 337 square foot (27.9 to 31.3 m2)), and adogtooth.[21] The airframe changes improved low-speed and high angle of attack flying, and gave more room for fuel tanks. The top speed was 704 mph (1,133 km/h) and minimum catapult speed was lowered to 127 knots (235 km/h; 146 mph). It also was now capable of breaking the sound barrier in a steep dive. All four ammunition boxes were mounted above the guns, in contrast to the split location of most previous F9Fs including the Panther. Visibility, which was already very good was improved with the F9F-8.[14][22][23][24] 601 aircraft were delivered between April 1954 and March 1957. Late production F9F-8 aircraft were given the ability to carry fourAIM-9 Sidewinderair-to-air missiles under the wings (the first Navy aircraft to deploy with the missiles). Most earlier aircraft were later modified to carry Sidewinders. A number were given also nuclear bombing equipment.[14][25] The F9F-8 was redesignatedF-9J in 1962. TheF9F-8B aircraft were F9F-8s converted into single-seatattack fighters, later redesignatedAF-9J.[26] The Navy acquired 377 two-seatF9F-8T trainers between 1956 and 1960. They were used for advanced training, weapons training, and carrier training, and served until 1974. They were armed with twin 20 mm (.79 in) cannon and could carry a full bombs or missiles load. In the 1962 redesignation, these were later calledTF-9J.[27]
A total of 110F9F-8Ps (photo-reconnaissance) were produced with an extensively modified nose carrying cameras. They were withdrawn after 1960 to reserve squadrons. In 1962, remaining F9F-6P and F9F-8P aircraft were re-designated RF-9F and RF-9J respectively.
Modifications of F9F-8 to convert to F9F-8P:
The F9F was known to be highly maneuverable and easy to fly.[11] Corky Meyer, who flew both the F9F Cougar andNorth American FJ-3 Fury, noted that compared to the latter the Cougar had a higher dive speed limit (Mach 1.2 vs Mach 1), a higher maneuvering limit of 7.5-g (compared to 6-g), and greater endurance.
"[The] Combat Air patrol mission was for two hours on station at 150 nmi (280 km) from the carrier. This required 2+30 takeoff, cruise, and landing endurance plus reserves. The F9F-6 could perform a three-hour CAP mission on internal fuel. The FJ-2 and -3 with external tanks had less than 1+30 mission time and the FJ-4 just met the mission requirement."[29]
The F9F Cougar was also a capable multi-role aircraft, which may explain why it was deployed less often than dedicated fighters.[29] In spite of engine problems that plagued the FJ-3, it was deployed for a longer period than the F9F Cougar. This was more likely attributable to the fact the F9F had an attack role that was being superseded by new jets such asA4D-1 Skyhawk, rather than any deficiency as a fighter.
"The reason the FJ-3 was deployed a little longer and a little more often (19 times vs 16) in fighter squadrons than the F9F-8 probably wasn't because it was the better fighter. More likely it was because it has a minimal capability as an attack aircraft, whereas the F9F-8 was good for that too, including nuclear weapon delivery. In effect the F9F-8 was a jet attack placeholder along with theF7U-3M, while the pipeline was being filled with theFJ-4Bs and A4Ds. As a result, the FJ-3 was the designated day fighter by default on most deployments."[29][30]
The first F9F-6s were assigned to fleet squadronVF-32 at the end of 1952. The first F9F Cougar squadron to actually deploy wasVF-24, assigned toUSS Yorktown in August 1953. It arrived too late to the Korean theater to participate in the air war.[11][22]
F9F-8s were withdrawn from front-line service in 1958–59, replaced byF11F Tigers andF8U Crusaders. The Naval Reserves used them until the mid-1960s, but none of the single-seat versions were used in the Vietnam War.
The only version of the Cougar to see combat was the TF-9J trainer (known as F9F-8T until 1962) during theVietnam War. Detachments of four Cougars served withUS MarinesHeadquarters and Maintenance Squadron 11 (H&MS-11) atDa Nang andH&MS-13 atChu Lai, where they were used for fast-Forward Air Control and the airborne command role, directing airstrikes against enemy positions inSouth Vietnam between 1966 and 1968.[31][32]
The TF-9J two-seat trainer had a long service with the U.S. Navy. It served as the Navy's advanced flight trainer for more than two decades.[24] The proposed Cougar modification (re-engined with a J52 engine) was rejected, and the Navy selected the TA-4F Skyhawk. The last Cougar was phased out when Training Squadron 4 (VT-4) re-equipped in February 1974. A F9F-8T, BuNo 14276, is displayed at theNational Naval Aviation Museum atNAS Pensacola, Florida.
The US Navy used the F9F Cougar to set the transcontinental crossing record on April 1, 1954. Three pilots from fleet fighter squadronVF-21 completed the 2,438-mile (3,924 km) flight in under four hours with LCDR F.X. Brady setting the quickest time of 3 hours, 45 minutes and 30 seconds. This was the first time the distance had been covered in under four hours. The three F9F-6 aircraftrefueled over Kansas from aNorth American AJ Savage, using an experimental refueling probe mounted on the nose.[10][33]
The U.S. Navy's flight demonstration team, theBlue Angels flew four different variants of F9Fs from the F9F-2 Panther to the F9F-8. The Blue Angels replaced their six F9F-5 Panthers with six F9F-6s in 1953. This was short lived however and the Navy subsequently took them for fleet use without using the planes in an air show. The F9F-6s were then replaced with overhauled F9F-5s until 1954 when the Blue Angels switched to the F9F-8. The Blue Angels used the F9F-8 until 1957 they were replaced by theGrumman F11F-1 Tiger, although one two-seat F9F-8T was retained for press and VIP flights.[34]
The only foreign air arm to use the F9F Cougar was theArgentine Naval Aviation, who also used the F9F Panther as well. Two F9F-8T trainers were acquired in 1962, and served until 1971. The Cougar was the first jet to break the sound barrier in Argentina.[35] One aircraft (serial 3-A-151) is on display at the Naval Aviation Museum (MUAN) atBahía Blanca, while the other was sold to a customer in the United States and subsequently lost in an accident on 31 October 1991.[36]
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Data from NAVAIR : Standard Aircraft Characteristics F9F-6 "Cougar" 1 July 1953,[70] Navair: Standard Aircraft Characteristics F9F-6 "Cougar" 1 July 1967[71]
General characteristics
Performance
Armament
Avionics
Related development
Aircraft of comparable role, configuration, and era
Related lists
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