Grumman F9F Panther
The Grumman F9F Panther is an early carrier-based jet fighter designed and produced by the American aircraft manufacturer Grumman. It was the first jet-powered fighter aircraft to see air-to-air combat with the United States Navy as well as being Grumman’s first jet fighter.
Development of the Panther commenced in the final months of World War II to harness the recent innovation of the jet engine. Grumman designed a single-engined, straight-winged day fighter that was armed with four cannons and could also carry a wide assortment of air-to-ground munitions. Production aircraft were typically powered by a single Allison J33 or Pratt & Whitney J48-P-2 turbojet engine. On 21 November 1947, the prototype performed its maiden flight, powered by an imported Rolls-Royce Nene engine. During September 1949, the F9F was cleared for flight from aircraft carriers.
The Panther was used extensively by the U.S. Navy and Marine Corps in the Korean War. On 3 July 1950, a F9F-3 recorded the first U.S. Navy air victory of the conflict, having shot down a propeller-powered Yak-9. In the Korean theatre, Panther pilots cumulatively claimed the shooting down of seven Mikoyan-Gurevich MiG-15s. During 1956, the type was withdrawn from front-line combat service, but remained in secondary roles, such as for training and with U.S. Naval Air Reserve and U.S. Marine Air Reserve units, until 1958. The Panther was also the first jet aircraft used by the Blue Angels aerobatics demonstration team, being flown in this capacity from 1949 through to late 1954. Future astronauts Neil Armstrong and John Glenn both flew the F9F extensively during the Korean War.
While Australia was interested in the Panther during the late 1940s, the nation ultimately opted for the Gloster Meteor F.8 and the CAC Sabre instead. The aircraft's only export customer was Argentina, where it became the first jet aircraft to be operated by the Argentine Naval Aviation. It was operated mainly from land, as the catapults of the aircraft carrier ARA Independencia lacked sufficient power to readily launch the F9F. Several Panthers participated in the 1963 Argentine Navy Revolt, firing upon Argentine Army forces sent to quell the revolt. During 1969, it was withdrawn from Argentine service due to a lack of spare parts.
Grumman would develop the F9F design in response to U.S. Navy interest, producing the swept wing Grumman F-9 Cougar.
Design and development
Background
The origins of the Panther can be traced back to development studies performed by Grumman into jet-powered fighter aircraft near the end of World War II. The company was keen to capitalise on the emergence of the first practical jet engines by integrating them into a new aircraft design. This design, which was internally designated G-75, was submitted to a United States Navy competition that sought a jet-powered night fighter to equip its aircraft carriers with. However, on 3 April 1946, it was announced that the Douglas F3D Skyknight, a competing two-seat aircraft powered by four Westinghouse J30 turbojets, had been selected. On 11 April 1946, the Navy's Bureau of Aeronautics issued a development contract to Grumman to produce a pair of G-75 prototypes, which were given the Navy designation XF9F-1, in case development of the Skyknight encountered severe problems.Shortly thereafter, Grumman recognised that the G-75 did not have much potential for either performance or growth; the company had already undertaken work on a completely different single-engine day fighter, the G-79. In a bureaucratic maneuver, BuAer opted not to cancel the G-75 contract, but instead changed the wording to include three prototypes of the entirely different G-79. It was this design that became the Panther.
At that time, the few American engines that were available for use, such as the Allison J33 and Westinghouse J34, were not considered to be sufficiently reliable; thus, the Navy specified the imported Rolls-Royce Nene turbojet, which was also more powerful, at of thrust. Production aircraft were to also be powered by the Nene, built under license by Pratt & Whitney as the J42.
Flight testing
On 21 November 1947, the prototype Panther conducted its maiden flight, piloted by test pilot Corky Meyer. It was followed by the second prototype only five days later. Initial issues with directional and longitudinal stability were encountered, but were quickly rectified. During one early land-based arresting gear test, the detachable rear section of the aircraft unintentionally came off; remedial changes were made to avoid any future repetition.During May 1949, carrier suitability trails commenced. In September 1949, the F9F was cleared for flight from aircraft carriers. During the development phase, Grumman decided to change the Panther's engine, selecting the Pratt & Whitney J48-P-2, a license built version of the Rolls-Royce RB.44 Tay. The other engine that had been tested was the Allison J33-A-16. The armament was a quartet of 20 mm guns, the Navy having already switched to this caliber. In addition, the Panther was soon armed with underwing air-to-ground rockets and up to of bombs.
From 1946, interest in developing an aircraft that harnessed the increasingly popular swept wing grew and, following concerns that the Panther was inferior to its MiG opponents over the skies of Korea, Grumman launched work on a conversion project, known as Design 93. This effort resulted in a swept-wing derivative, the F9F Cougar, which retained the Panther's designation number. Later stage development work on the Panther continued, being largely focused on engine improvements, expanding fuel capacity, and the use of alternative munitions.
In 1949, the Panther was considered by the Australian government, as a possible locally-built replacement for the Mustang Mk 23 and De Havilland Vampire then operated by the Royal Australian Air Force. The other designs considered initially were an Australian design, the CAC CA-23 and the Hawker P.1081. By mid-1950, however, RAAF Mustangs were in action in Korea and seen as highly vulnerable to the MiG-15. An immediately available stop-gap in the shape of the Gloster Meteor F.8 was operated by the RAAF in Korea from July 1951.
Operational history
US Navy
The Panther was the primary jet fighter and ground-attack aircraft of both the US Navy and USMC during the Korean War. It was the widest used Navy jet fighter of the conflict, cumulatively flying 78,000 sorties. F9F-2s, F9F-3s and F9F-5s, as rugged attack aircraft, were able to sustain operations despite being frequently opposed by intense anti-aircraft fire. The pilots also appreciated the air conditioned cockpit, which made for a welcome change from the humid environment of piston-powered aircraft.On 3 July 1950, Lieutenant, junior grade Leonard H. Plog, of VF-51, flying an F9F-3 scored the first US Navy air victory of the war by shooting down a propeller-powered Yak-9.
Despite their relatively low speed, Panther pilots also claimed seven Mikoyan-Gurevich MiG-15s, for the loss of two F9Fs. The first MiG-15 was downed on 9 November 1950, by Lieutenant Commander William Amen of VF-111 flying an F9F-2B, during a UN Command attack on the Sinuiju bridges, near the mouth of the Yalu River. Two more MiG-15s were downed on 18 November 1950.
On 18 November 1952, the American aircraft carrier and three other carriers were operating in the Sea of Japan conducting air strikes against the North Korean city of Hoeryong. The group launched four F9F's for a combat patrol near the North Korean border with China. The group's leader suffered mechanical problems and returned to the carrier together with his wingman. Lt Royce Williams of VF-781, flying off and his wingman continued on the mission. They then identified seven Soviet Naval Aviation MiGs heading towards the task force from the Russian mainland. The naval commanders therefore ordered the two F9Fs to position themselves between the MiGs and the carrier group.
During this maneuver, four Soviet MiG-15s opened fire, despite the fact that the countries were not at war. Williams opened fire on the tail MiG, which dropped out of formation, and was followed down by Williams's wingman. What followed was a 35-minute dogfight between Williams and six MiG-15s. The MiG-15 was a more capable plane, but Williams nevertheless succeeded in shooting down three more. He ascribed this to both sides doing as they were trained, but the Soviet pilots making mistakes. While heading back to the carriers, Williams was out of ammo, but still had one MiG on his tail. The re-appearance of his wingman on the MiG's tail then scared this one off. By that time Williams's plane was so damaged that he could not turn sideways anymore. Oriskany was therefore aligned with the plane, so he could land. After landing, his Panther was found to have 263 hits by cannon shells or fragments and was beyond repair. It was therefore pushed overboard.
The engagement is little-known for two reasons. The US feared that publication of the incident could increase tensions with the Soviet Union. Another reason was the involvement of the US National Security Agency – the existence of which was then top secret – in planning the mission; the MiGs were intercepted as a result of intelligence provided by the NSA. The four MiGs that were shot down were flown by Soviet Naval Aviation pilots: Russian sources confirmed Williams's claims, 40 years later, stating the pilots lost were Captains Belyakov and Vandalov, and Lieutenants Pakhomkin and Tarshinov.
As the conflict progressed, Panthers became primarily tasked with ground attack missions. Attacks upon hostile anti-aircraft equipment were commonly conducted. This was a risky mission type, with numerous Panthers being damaged or even lost to fire from the same ground batteries that they were seeking to neutralize. Furthermore, the danger posed by these systems increased over time as more capable AA apparatus was supplied to the North Korean force. Panthers also routinely undertook aerial reconnaissance missions over Korea. Starting in 1952, the Panther began to be supplemented by the newer Cougar derivative in the theatre.
Future astronaut Neil Armstrong flew the F9F extensively during the Korean conflict, although he ejected from one of the aircraft after it was brought down by a wire strung across a valley in 1951. Future astronaut John Glenn and Boston Red Sox all-star baseball player Ted Williams also flew the F9F as Marine Corps pilots.
During 1956, the Panther was withdrawn from frontline combat service, having been displaced by new fighter aircraft, including its swept-wing Cougar derivative. However, the type remained active in secondary roles, such as for training and with U.S. Naval Air Reserve and U.S. Marine Air Reserve units, until 1958. The Navy's Blue Angels flight demonstration team used the Panther for four years, beginning in 1951. The Panther was the Blue Angels' first jet. Some Panthers continued to serve in small numbers into the 1960s. From September 1962, surviving operational Panthers were designated F-9 within the new combined US tri-service designation system.