The Douglas F3D Skyknight (later redesignated F-10 Skyknight) is an American twin-engined, mid-wing jet fighter aircraft designed and manufactured by the Douglas Aircraft Company.
It was designed in response to a 1945 United States Navy requirement for a jet-powered, radar-equipped, carrier-based night fighter. Douglas designed the aircraft around the bulky air intercept radar systems of the era, resulting in a wide, deep, and roomy fuselage that accommodated its two-man crew. An initial contract was issued to Douglas on 3 April 1946. The XF3D-1 prototype performed its maiden flight on 23 March 1948. During June 1948, a production contract for 28 F3D-1 production aircraft was received. It was equipped with a Westinghouse AN/APQ-35 fire control system, which incorporated three separate radars and was an essential component of its night fighter operations.
The F3D saw service with the United States Navy and United States Marine Corps. Its primary mission was to locate and destroy enemy aircraft at night.Standard Aircraft Characteristics F3D-2 Skyknight NAVAER 1335C REV. 10-51. The Skyknight was not produced in great numbers, yet it achieved numerous firsts in its role as a night fighter during the Korean War, where the type frequently escorted Boeing B-29 Superfortresses on night bombing missions. While it never achieved the fame of the North American F-86 Sabre, it downed several Soviet-built MiG-15s as a night fighter over Korea. It suffered only a single air-to-air loss against a Chinese MiG-15, which occurred on the night of 29 May 1953."Defense POW/Missing Personnel Office: Korean War Air Loss Database (KORWALD)." dtic.mil. Retrieved: 10 August 2013.Zhang 2002, pp. 194–195. A total of 237 F3D-2s were completed before production was terminated on 23 March 1952.
The Skyknight played an important role in the development of the radar-guided AIM-7 Sparrow missile, which led to further guided air-to-air missile developments. It also served as an electronic warfare platform in the Vietnam War as a precursor to the EA-6A Intruder and EA-6B Prowler. The aircraft is sometimes unofficially called "Skynight", dropping the second "k". The unusual, portly profile earned it the nickname "Willie the Whale"."Douglas Skyknight." Boeing history. Retrieved: 23 August 2010. Some Vietnam War U.S. Marine veterans have referred to the Skyknight as "Drut", whose meaning becomes obvious when read backwards. This may be in reference to its age, unflattering looks, or the low-slung air intakes that made it vulnerable to foreign object damage (FOD).
Design and development Origins The F3D was not intended to be a typical sleek and nimble dogfighter, but as a standoff night fighter, being outfitted with a powerful radar system and a second crew member. It originated in 1945 with a US Navy requirement for a jet-powered, radar-equipped, carrier-based night fighter. The Douglas team led by Ed Heinemann designed the aircraft around the bulky air intercept radar systems of the time, placing the pilot and radar operator in side-by-side seating.Donald 1997, p. 365.Thomason 2008, pp. 61-62. The result was an aircraft with a wide, deep, and roomy fuselage. Aviation author Joe Copalman observed that the F3D was a relatively conventional aircraft, despite its use of jet propulsion, the design team having opted for features such as a straight wing and traditional tail unit.Copalman 2022, p. 6.
A large and relatively flat forward windshield was used; while not conducive to high speed flight, it provided distortion-free external visibility, something that was particularly valued for a night fighter at that time. The design team opted not to use tip tanks due to the fuselage already permitting sufficient fuel capacity and the difficulty involved in properly combining the tanks with a folding wing mechanism. The use of ejection seats was also considered but decided against as their inclusion would have necessitated a jettisonable canopy, made pressurizing the cockpit more difficult, and added weight. Instead, an escape tunnel was used, similar to the arrangement used in the Douglas A-3 Skywarrior.Copalman 2022, p. 12. The stick was extendable so that more force could be exerted upon it by the pilot as a fallback measure in the event of a hydraulic failure.Thomason 2008, p. 63.
The XF3D-1 was selected over a competing submission, Grumman Aircraft Engineering Corporation's G-75 twin-seat, four-engined, Westinghouse J30-powered night fighter design (similar layout to their Tigercat), leading to an initial contract being issued on 3 April 1946. The US Navy's Bureau of Aeronautics (BuAer) also issued a contract to Grumman for two G-75s (BuAer designation XF9F-1) experimental aircraft on 11 April 1946 in case the Skyknight encountered problems. Shortly thereafter, Grumman recognised that the G-75 would not be a successful aircraft, instead, the company had been working on a completely different single-engined day fighter, initially known as the G-79; it would later become the Grumman F9F Panther.Sullivan 1982, pp. 4, 6.
Into flight
On 23 March 1948, the XF3D-1 performed its maiden flight from Douglas' El Segundo facility with test pilot Russell Thaw at the controls. While wind tunnel testing had indicated the need for aerodynamic changes, such as the addition of wing fences, flight testing provided these to be unnecessary. Flight testing continued at El Segundo up until October 1948, after which the three prototypes were transported to Muroc Air Force Base (later renamed Edwards Air Force Base) to participate in service trials. These units were powered by a pair of Westinghouse J34-WE-24 turbojets, capable of thrust, which were installed underneath the roots of then-standard straight wings of the early jet era. During June 1948, a production contract for 28 F3D-1 production aircraft, powered by improved J34-WE-32 engines, was issued; relatively little external changes were made between the prototype and production aircraft, save for the enlargement of the engine nacelles.Thomason 2008, p. 61. The first production aircraft made its first flight on 13 February 1950.Gunston 1981, p. 172. That same month, shore-based testing was concluded.
As a night fighter that was not expected to be as fast as smaller daylight fighters, the expectation was to have a stable platform for its radar system and the four 20 mm cannon mounted in the lower fuselage. Yet, the F3D was capable of outturning a MiG-15 jet fighter.Dorr 1994, p. 154. The fire control system in the F3D-1 was the Westinghouse AN/APQ-35. The AN/APQ-35 was advanced for the time, a combination of three different radars, each performing separate functions: an AN/APS-21 search radar, an AN/APG-26 tracking radar, both located in the nose, and an AN/APS-28 tail warning radar.Badrocke 1993, pp. 41, 44–45. The AN/APS-21 was capable of detecting aircraft at distances up to 20 miles away while the AN/APG-26 could achieve a weapons lock up to 2.25 miles away and the AN/APS-28 was effective up to 10 miles away.Thomason 2008, pp. 61, 63. The complexity of this vacuum tube-based radar system, produced before the advent of semiconductor electronics, required intensive maintenance to keep it operating properly.
The F3D-1 was followed by the F3D-2, which was first ordered in August 1949. This model was intended to have Westinghouse J46 engines in enlarged nacelles to replace the J34-WE-32 engines of the F3D-1; however, on account of development problems with the J46, the F3D-2 was initially fitted with J34-WE-36 engines instead. Higher-thrust J34-WE-38 engines were installed later, noticeably increasing the aircraft's performance. Additional changes on the F3D-2 included the incorporation of an improved Westinghouse AN/APQ-36 fire control system, autopilot, air conditioning, and a bulletproof windscreen.Copalman 2022, p. 7.Thomason 2008, p. 64. A total of 237 F3D-2s were built prior to production being terminated on 23 March 1952. At one stage, a higher performance F3D-3 variant, equipped with swept wings and J46 engines, was planned, yet work was cancelled after the J46's development was so troublesome that officials opted to terminate work.
Operational history
Korean War The 28 F3D-1s produced were primarily used to train F3D crews; as such, this model did not see combat in the Korean War.Thomason 2008, pp. 64-65. The F3D-2 Skyknight was only operated in the Korean theatre by United States Marine Corps (USMC) land–based squadrons, beginning in August 1952.Copalman 2022, pp. 6-8. The first aircraft to arrive in Korea were initially unable to commence operations due to a lack of gun barrel extensions, which were necessary to fire the aircraft's cannons safely; the first aircraft to be modified was on 9 August 1952, permitting live operations to commence in the following weeks.Copalman 2022, p. 8. Prior to this, exercises were conducted to develop closer coordination with ground controllers, upon whom the F3D-2s were dependent during their night time operations.Copalman 2022, pp. 8-9.
From the onset of operations, hostile jamming from inside North Korea proved to be effective against onboard radar.Copalman 2022, p. 9. This factor contributed to Skyknight pilots often experiencing difficulty when attempting to close in, identify, and lock onto suspected hostile aircraft. Ground-based anti-aircraft artillery, which was often equipped with radar-guided search lights, proved to be more of a threat to night time operations over Korea than the occasional MiG-15; such aircraft often acted as bait, attempting to draw the Skyknights into coordinated traps.Copalman 2022, pp. 10-11. According to Copalman, the AN/APS-28 tail warning radar unit proved quite advantageous in terms of situational awareness.Copalman 2022, pp. 11-12.
The Skyknight was responsible for downing more enemy aircraft over Korea than any other single type of naval aircraft."Douglas F3D-2 Sky Knight." Flying Leatherneck Historical Foundation and Aviation Museum. Retrieved: 16 December 2007. The first air-to-air victory was recorded on the night of 2 November 1952 by a USMC F3D-2 piloted by Major William T. Stratton Jr., and his radar operator, Master Sergeant Hans C. Hoglind of VMF(N)-513 Flying Nightmares, Major Stratton shot down what he believed was a Yakovlev Yak-15 (even though no Yak-15s were reported in Korea)Goebel, Greg."The Douglas F3D Skyknight." Airvectors.net, 1 September 2002. Retrieved: 2 August 2013. which was the first successful night radar interception by a jet of another jet.Dorr 1994, p. 143. The Skyknight claimed its first MiG-15 kill on 8 November 1952, when Captain O.R. Davis and Warrant Officer D.F. "Ding" Fessler downed a MiG-15 northwest of Pyongyang. USMC pilot Lt. Joseph Corvi and his radar operator Sergeant Dan George set another record with the Skyknight on the night of 10 December 1952, when they downed the first aircraft by an aircraft with a radar track and lock-on and without visual contact. They performed the feat by using their radar to lock onto a Polikarpov Po-2 biplane. They were also credited with another probable kill that night.Dorr 1994, p. 149.
In January 1953, the number of USMC Skyknights in Korea was doubled to 24; this increase allowed them to effectively escort B-29 Superfortresses on night bombing missions.Dorr 1994, p. 153.Thomason 2008, p. 66. On 12 January 1953, an F3D-2 of VMF(N)-513 that was escorting B-29s on a night bombing mission was vectored to a contact and shot down the fourth aircraft by a Skyknight.Dorr 1994, p. 154. By the end of the war, Skyknights had claimed six enemy aircraft (one Polikarpov Po-2, one Yakovlev Yak-15 and four MiG-15s).Grossnick 1997, p. 768.