Douglas F3D Skyknight
The Douglas F3D 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. 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 only sustained a single air-to-air loss against a Chinese MiG-15, which occurred on the night of 29 May 1953. 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". 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.
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. 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.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. 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.
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, leading to an initial contract being issued on 3 April 1946. The US Navy's Bureau of Aeronautics also issued a contract to Grumman for two G-75s 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.
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 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. The first production aircraft made its first flight on 13 February 1950. 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. 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. 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. 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. 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. The F3D-2 Skyknight was only operated in the Korean theatre by United States Marine Corps land–based squadrons, beginning in August 1952. 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. 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.From the onset of operations, hostile jamming from inside North Korea proved to be effective against onboard radar. 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. According to Copalman, the AN/APS-28 tail warning radar unit proved quite advantageous in terms of situational awareness.
The Skyknight was responsible for downing more enemy aircraft over Korea than any other single type of naval aircraft. 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-513 Flying Nightmares, Major Stratton shot down what he believed was a Yakovlev Yak-15 which was the first successful night radar interception by a jet of another jet. 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.
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. On 12 January 1953, an F3D-2 of VMF-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. By the end of the war, Skyknights had claimed six enemy aircraft.
In May 1953, Composite Squadron 4 Detachment 44N was deployed to Korea via the U.S.S. Lake Champlain. They sailed through the Mediterranean Sea and on to the eastern Korean coast. After arriving, VC-4 flew a few patrols from the ship, but it was soon apparent that the planes were not well suited for the ships wooden deck. The exhaust nozzles on the F3D were angled slightly down and during take-off, the jet's exhaust scorched the teakwood deck of the ship. After each take-off the deck hands would rush out onto the deck and put out the smoldering fires. After several of these fire drills, the Ship's Captain insisted that VC-4 be transferred to the mainland and join up with VMF 513.
On 23 June 1953, VC4 joined with VMF 513 at K-6 Airbase south of Seoul. The mission of VC-4 DET44N as directed by Commander Task Force NINETY-ONE and as employed as an integral part of Marine All Weather Fighter Squadron 513 based ashore, providing night fighter escort for U.S. Air Force medium bomber strikes on targets in North Korea and providing night combat air patrols in the Chodo Island area, extending from the Haeju peninsula to the Yalu River.
One F3D, piloted by LTJG Bob Bick and his RO, Chief Petty Officer Linton Smith, was lost to enemy fire on 2 July 1953. This aircraft was part of the detachment from Fleet Composite Squadron FOUR at NAS Atlantic City.
Operational Comments June 1953 through July 1953
The following are excerpts from Carrier Air Group FOUR, Action Report of VC-4 Detachment 44N for period 19 June 1953 to 27 July 1953.
1. The radar equipment in the F3D-2 is excellent, however the relatively low speed and slow rate of climb of the aircraft prohibits exploiting the advantage of the excellent radar coverage against high speed enemy jets.
2. The extreme visibility of the glow from the engines' tailpipes offers an easy target for a pursuer and a detriment to the evasiveness of the aircraft.
3. The near vertical forward windshield and the lack of windshield wipers, limits the visibility of the pilot, on a final GCA approach in heavy rain, to the curved side panel. Under such conditions of heavy rain, forward visibility is extremely poor.
While the Skyknight lacked the swept wings and high subsonic performance of the MiG-15, its powerful fire control system enabled it to find and shoot down other fighters at night, while most MiG-15s could only be guided by ground-based radar.