F9F-6 "Cougar" of Fighter Squadron 112 (VF-112) during field carrier landing practice at NAS Miramar.
This aircraft is being flown by Ensign
Bob Jellison, USNR

ABOUT THE GRUMMAN F9F-6 "COUGAR"

History

Grumman received a Navy contract on 16 December 1946 to produce a jet powered, straight wing, carried based fighter. The aircraft Grumman proposed first flew on 21 November 1947 and was eventually designated and named the F9F-2 Panther. It was first delivered to Navy squadron in May 1949 and remained in service until October 1958. The Navy accepted a total of 1,388 Panthers with designations of F9F-2, F9F-3, F9F-4 and F9F-5.

The Panther’s success led Grumman to design a swept wing derivative and propose it to the Navy.

The new design retained the fuselage of the Panther but included a swept wing and tail. The Navy awarded Grumman a contract for this new aircraft on 2 March 1951. It made its first flight on 20 September and was named the Cougar but retained the F9F designation. The Cougar was first delivered to the Navy in November 1952 and remained in squadron until February 1960. The Navy accepted a total of 1,985 Cougars with the designations F9F-6, F9F-7 and F9F-8.

Concept to production

The surprise appearance of the swept-wing MiG-15 in November 1950 suddenly rendered obsolete the straight-wing Grumman F9F-2 and McDonnell F2H-2, the Navy's most advanced fighters then in squadron service. Work on a swept-wing Panther, which had been shelved because of the poor low-speed behavior of swept-wing aircraft. was resumed on a high priority basis.

A contract for the modification of three F9F-5 airframes was awarded in March of 1951, and the F9F-6 prototype first flew six and a half months later The first F9F-6s were delivered to VF-32 in November 1951, just one year after the MiG- I5's debut in Korea.



Ensign Bob Jellison

Airframe

Conceived as a straightforward derivative of the Panther, the F9F-6 retained the fuselage, vertical tail surfaces, power plant, and undercarriage of the F9F-5 and was fitted with wings swept at 35 degrees at quarter chord and with swept horizontal tail surfaces. To compensate for the increase in approach and stalling speeds resulting from the use of swept wings, the chord of the leading-edge slats and that of the trailing-edge flaps were increased and much larger split flaps were fitted beneath the center section. Other modifications included the lengthening of the forward fuselage by 2 ft, the forward extension of the intake-housing wing center section, the enlargement of the wing root fillets, and the use of a broader chord lower rudder section linked to the rudder pedals and of an upper rudder section of unchanged dimension but linked to a yaw damper. Furthermore, as the tip tanks had to be dispensed with, the resulting reduction in fuel capacity was made up partially by increasing the size of the forward fuselage fuel tank and adding bladder-type tanks in the wing Ieading-edge. (Nevertheless, total internal fuel capacity decreased from 1,003 to 919 US gal.)

Controls

The first prototype had cotiventional horn-balanced ailerons for lateral control and conventional tab geared elevators for longitudinal control. However, with these surfaces, the F9F-6 experienced control reversal at high speed and poor lateral and longitudinal control. The use of an hydraulically-operated 'flying tall' easily cured the longitudinal control deficiency but lateral control remained unsatisfactory until the horn balanced ailerons were replaced by' flaperon/'flaperette' spoilers fitted on the wing upper surface at about 75 per cent of the chord line. The flaperon was ahead of the flaperette and under normal flight conditions both of these spoiler sections were hydraulically operated as a single surface. In an emergency, the flaperette section was operated independently by means of a separate hydraulic System. Large fences were also added during trials to inhibit spanwise flow and preserve lateral control effectiveness. The resulting F9F-6 demonstrated better carrier handling characteristics than the F9F-5, while critical Mach number was increased from 0.79 to 0.86 at sea level and to 0.895 at 35,000 ft. 

Powerplant

706 F9F-6's were produced, the majority of which were powered by the 7,250-lb thrust J48-P-8 (some later aircraft were powered by the J48-P-813, which were modified J48P-8s with titanium impeller inducers.

Armament

All Cougars were armed with four 20-mm cannon and had two wing racks for 1,000-lb bombs or, more usually, 150-US gal drop tanks. In service, a number of F9F-6s were fitted with a UHF homing antenna in a faring beneath the nose and a few had an in-flight refueling probe installed in the nose.



F9F-6 taxiing onto the starboard catapault



VF-112 "Cougar" landing on the USS Kearsarge (note the 12 arresting wires on this straight deck ).

Trials to delivery

In spite of the need to develop and evaluate these major control system changes, to the credit of the Grumman engineering team flight trials proceeded remarkably quickly and production F9F-6s were ready for squadron delivery only fourteen months after the first flight of the prototype. Equally impressive were the ease with which this stop-gap design was further developed and its longevity.



Field carrier landing practice at NAS Miramar

Deployment history

Developed in great haste during the Korean War as a stop-gap design to provide the Navy with a fighter having performance comparable to that of the MIG-15, the Cougar was made ready for squadron assignment in a remarkably short time. Beginning in November 1952, when VF-32 became the first fleet squadron to convert to Cougars, F9F-6s and F9F-7s quickly re-equipped no fewer than twenty Navy fighter squadrons. Eight of these squadrons later converted to the more capable F9F-8, and this variant was also assigned to seven other squadrons which had not previously been flying Cougars. In addition, four Navy attack squadrons were equipped with Cougars before converting to Douglas A4D Skyhawks and three reconnaissance squadrons flew F9F-6Ps and/or F9F-8PS.

Too late to fly combat sorties in Korea, Cougars made numerous deployments to the Pacific, the Atlantic, and the Mediterranean during which their pleasant handling characteristics and strong airframe well suited to the rigors of carrier operations earned praise from their pilots.

By the mid-1950s, Cougars were the most numerous carrier-based fighters. However, it was already evident that these aircraft had been rendered obsolete by rapid technological development and would only have abbreviated lives as front-line aircraft. Supersonic aircraft, notably Grumman Tigers and the LTV Crusaders, were about to replace them in the fighter and reconnaissance roles and Douglas Skyhawks were destined to become the Navy's standard jet-powered light attack aircraft.

The last Cougar, a two-seat F9F-8T advanced trainer, was delivered in February 1960, and the last Cougars were finally phased out in February 1974.

Record flights

Notable were the two record US transcontinental crossings. On April 1st, 1954, flying probe-equipped F9F-6s and refueling in flight over Kansas, three VF-21 pilots made the first such flight in less than four hours, completing the 2,438 miles in 3 hr 46 minutes.

Photo Cougars

Sixty F9F-6 airframes were fitted by Grumman with a vertical and oblique camera installation in place of the cannon and were delivered as F9F-6Ps between June 1954 and March 1955



Ensign Bob Jellison