Article 4318 of rec.aviation.military:
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From: jfb@usgp1.ih.att.com (Joe Baugher)
Subject: Grumman F-9 Panther/Cougar (8 of 13)
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Summary: F9F-6 Cougar 
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Date: Mon, 24 Oct 1994 03:24:13 GMT
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The XF9F-2/XF9F-3 Panther contract awarded in October of 1946 had 
included a clause calling for design data on a swept-wing version.  
However, Grumman was worried about the poor low-speed characteristics 
of swept-wing aircraft, and prevailed upon the Navy to postpone work 
on a swept-winged version of the Panther.  

However, the development of a swept-wing Panther was made more urgent 
by the appearance of the MiG-15 in Korea in November of 1950.  The 
MiG-15 was powered by derivatives of the same Rolls-Royce Nene as was 
the Panther, but was nearly 100 mph faster.  The very next month, the 
Navy and Grumman both agreed that it was urgent to press forward with 
the development of a swept-wing version of the Panther.  A contract 
for the modification of three F9F-5 airframes was signed on March 2, 
1951.  The project was assigned the company designation Design 93.  

Grumman's Design 93 was a more-or-less straightforward swept-wing 
conversion of the Panther.  It retained the fuselage, vertical tail, 
engine, and undercarriage of the F9F-5, but was fitted with wings 
swept at 35 degrees and with swept horizontal tail surfaces.  In order 
to reduce the approach and stalling speeds to acceptable levels, the 
chord of the leading-edge slats and the trailing-edge flaps were both 
increased.  Much larger split flaps were fitted underneath the 
fuselage center section.  The fuselage was increased in length by 2 
feet, and the the wingroot-mounted intakes were extended farther 
forward and the wing root fillets were enlarged.  A broader chord 
lower rudder section was fitted, linked to the rudder pedals.  The 
upper rudder section was unchanged, but was linked to a yaw damper.  
The wingtip tanks had to be eliminated, and the resulting reduction in 
fuel capacity was partially offset by increasing the size of the 
forward-fuselage fuel tank and by adding bladder-type fuel tanks in 
the wing leading edge.  Nevertheless, the internal fuel capacity was 
only 919 US gallons, as compared with 1003 US gallons for the F9F-5.  

Since the Design 93 was so different from the F9F-5, one might have 
expected that the Navy would assign a new manufacturer type sequence 
number to it.  Since the next available number for Grumman was 11, the 
new design by all rights should have been designated F11F-1.  However, 
for some reason, the Navy decided to assign it the next configuration 
sequence number in the original Panther manufacturer type sequence, 
and the swept-wing version of the Panther was designated F9F-6.  
However, a new name was given to the swept-wing F9F-6--Cougar, thus 
continuing the tradition of assigning feline names to Grumman-built 
fighter aircraft.  

Two flying prototypes (126670 and 126672) and a static test airframe 
(126671) were obtained by converting three uncompleted F9F-5 airframes 
to F9F-6 configuration.  Work on the swept-wing Cougar proceeded quite 
rapidly and the first F9F-6 (BuNo 126670) was ready for its first 
flight only six months after the signing of the contract.  It took to 
the air for the first time on September 20, 1951, with test pilot Fred 
C.  Rowley at the controls.  The plane was powered by a Pratt & 
Whitney J48-P-6 turbojet rated at 6250 lb.st. takeoff dry and 7000 
lb.s.t. takeoff with water injection.  It had conventional 
horn-balanced ailerons for lateral control and conventional tab geared 
elevators for longitudinal control.  Early test flights revealed that 
the F9F-6 had a tendency towards control reversal at high speeds, and 
had rather poor lateral and longitudinal control.  The adoption of an 
all-flying horizontal tailplane cured the reversibility problem.  The 
lateral control problem was cured by the addition of 
"flaperon/flaperette" spoilers fitted to the upper wing surfaces.  In 
normal flight, both of these spoiler sections operated as a single 
unit, but the flaperette section could operate independently.  Large 
wing fences were found necessary to inhibit spanwise airflow and to 
preserve lateral control effectiveness.  

To everyone's surprise and amazement, the prototype F9F-6 actually had 
better carrier handling characteristics than the straight-winged 
F9F-5.  The critical Mach number was increased from 0.79 to 0.86 at 
sea level and to 0.895 at 35,000 feet.  The prototype (126670) was 
later re-engined with a YJ48-P-8 turbojet rated at 7250 lb.s.t.  
without the need for water injection.  

The first 30 production F9F-6s were powered by the 7000 lb.s.t.  
J48-P-6A, but the remainder of the F9F-6 order was powered by the 7250 
lb.s.t. J48-P-8 turbojet.  The built-in armament consisted of four 
20-mm cannon.  In addition, the aircraft had two wing racks for 
1000-pound bombs or 150-US gallon drop tanks.  

The first unit to receive the F9F-6 was VF-32, which converted to the 
Cougar in November of 1952.  However, the Cougar was too late to fly 
combat sorties in Korea.  The last of 646 F9F-6 Cougars was delivered 
on July 2, 1954.  

In 1953, the *Blue Angels* flight demonstration team transitioned from 
F9F-5 Panthers to F9F-6 Cougars.  However, the team's Cougars were 
urgently needed by operational squadrons, and the *Blue Angels* were 
forced to re-equip briefly with F9F-5s.  In 1954, the *Blue Angels* 
traded in their F9F-5s for F9F-8 Cougars.  

In service, F9F-6s were often fitted with a UHF homing antenna in a 
fairing underneath the nose.  A few even had an inflight refuelling 
probe installed in the nose.  

Three probe-equipped F9F-6s flown by VF-21 made the first US 
transcontinental crossing in less than four hours on April 1, 1954, 
the fastest time being 3 hours 45 minutes 30 seconds for a distance of 
2438 miles.  

Sixty F9F-6 Cougar airframes were fitted by Grumman with a camera 
installation in the nose in place of the cannon, and were were 
delivered under the designation F9F-6P between June 1954 and March 
1955.  The nose was slightly longer (the length increasing from 41 
feet 5 inches to 42 feet 1 7/8 inches).  All armament was deleted.  

Following the withdrawal of F9F-6s from active service, several F9F-6s 
were modified as F9F-6D drone directors or as F9F-6K drones.  The 
F9F-6K2 designation identified F9F-6Ks which were equipped with 
modernized equipment, as a well as a number of F9F-6s which were 
fitted directly with this newer equipment.  The designation F9F-6PD 
was assigned to two F9F-6Ps (BuNos 127475 and 128308) that were 
modified as target controller planes.  

In 1962, the Defense Department introduced the new Tri-Service 
designation scheme under which the separate USAF/Navy designations 
were replaced by a new unified designation system.  This required that 
all existing Navy aircraft be redesignated.  The F9F-6 was 
redesignated F-9F, with the F9F-6D, F9F-6K, and F9F-6K2 being 
redesignated DF-9F, QF-9F, and QF-9G respectively.  The F9F-6P 
reconnaissance aircraft was redesignated RF-9F.  

Serial numbers of Grumman F9F-6 Cougar:

126257/126264		Grumman F9F-6 Cougar
126670/122672		Grumman XF9F-6 Cougar
127216/127470		Grumman F9F-6 Cougar
127473/127492		Grumman F9F-6P Cougar
128055/128294		Grumman F9F-6 Cougar
128295/128310		Grumman F9F-6P Cougar
130870/130999		Grumman F9F-6 Cougar
131000/131062		Grumman F9F-6 Cougar
131252/131255		Grumman F9F-6P Cougar
134446/134465		Grumman F9F-6P Cougar

Specification of Grumman F9F-6 Cougar:  

One Pratt & Whitney J48-P-8 turbojet rated at 6250 lb.s.t. dry and 
7250 lb.s.t. with water injection.  
Performance:  Maximum speed 654 mph at sea level, 591 mph at 35,000 
feet.  Cruising speed 541 mph.  Stalling speed 128 mph.  Initial climb 
rate 6750 feet per minute.  An altitude of 20,000 feet could be 
attained in 4 minutes.  Service ceiling 44,600 feet.  932 miles normal 
range.  
Internal fuel was 919 US gallons.  With two 150-gallon drop tanks, 
total fuel load was 1219 US gallons.  
Dimensions:  wingspan 34 feet 6 inches, length 41 feet 5 inches, 
height 12 feet 4 inches, wing area 300 square feet.  
Weights:  11,255 pounds empty, 18,450 pounds loaded, 21,000 pounds 
maximum takeoff.  
Armament:  The armament consisted of four 20-mm cannon in the nose 
plus two underwing racks for 1000-pound bombs or 150-US gallon drop 
tanks.  

Sources:

    United States Navy Aircraft Since 1911,  Gordon Swanborough and
    Peter M. Bowers, Naval Institute Press, 1990.

    The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.

    Grumman Aircraft Since 1929, Rene J. Francillon, Naval Institute
    Press, 1989.

    American Combat Planes, 3rd Enlarged Edition, Ray Wagner,
    Doubleday, 1982.

Joe Baugher			  **************************************
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