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Douglas F4D Skyray

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"F4D" redirects here. For the F-4D Phantom, seeMcDonnell Douglas F-4 Phantom II.

F4D (F-6) Skyray
Role Fighter aircraft
Manufacturer Douglas Aircraft Company
First flight 23 January 1951
Introduction 1956
Retired 1964
Status Retired
Primary users United States Navy
United States Marine Corps
Produced 1950–1958
Number built 422
Developed into Douglas F5D Skylancer

TheDouglas F4D Skyray(later redesignatedF-6 Skyray) is an Americancarrier-basedsupersonicfighter/interceptordesigned and produced by theDouglas Aircraft Company.It was the first naval fighter to exceed the speed of sound in level flight and the last fighter produced by theDouglas Aircraft Companyprior to its merger withMcDonnell Aircraftto becomeMcDonnell Douglas.

Development of the Skyray was started by Douglas during the late 1940s as theD-571-1design study. It was adelta winginterceptor capable of a high rate of climb as to permit the rapid interception of approaching hostile bombers. Douglas' proposal was selected by Navy officials to fulfil a formal requirement issued in 1948. The decision to adopt theWestinghouse J40turbojetengine to power it would lead to considerable difficulties later on as this engine would be cancelled prior to entering production. Aerodynamic issues would also lead to a protracted development cycle, considerable design changes being made even after themaiden flightof a production standard Skyray having taken place in June 1954. The Skyray was declared ready for fleet introduction in April 1956, permitting its entry to service with both theUnited States Navy(USN) andUnited States Marine Corps(USMC) shortly thereafter.

The Skyray had a relatively brief service life, during which it never participated in actual combat. Despite this, it was the firstcarrier-launched aircraft to hold the world's absolute speed record, having attained a top speed of 752.943 mph,[1][2](1,211.744 km/h).[3]It also set a new time-to-altitude record, flying from a standing start to 49,221 feet (15,003 m) in two minutes and 36 seconds, all while flying at a 70° pitch angle. The last Skyrays were withdrawn from service in February 1964, although a handful continued to be flown for experimental purposes byNational Advisory Committee for Aeronautics(NACA) up to the end of the decade. TheF5D Skylancerwas an advanced development of the F4D Skyray that ultimately did not enter service.

Design and development[edit]

The Skyray originated within a design study, theD-571-1,performed by Douglas and funded by theUnited States Navy(USN). It was a fast-climbing pure interceptor that used adelta wingconfiguration and powered by a pair ofWestinghouse J34turbojetengines, which were equipped withafterburnersfor bursts of additional acceleration.[4]The D-571-1 had a relatively thick wing with no conventional fuselage save for a pod-like cockpit in a forward position. A total of four 20mm cannons extended forward of theleading edgeof the wing; alternative armaments consisted of spin-stabilized rockets.[5]The design study had harnessed the designs and research of the GermanaerodynamicistAlexander Lippisch,who moved to the United States following the end ofWorld War II,and whose work had been examined by several of Douglas's design team.[6]In June 1947, the Navy issued a contract to Douglas to proceed with preliminary investigation and engineering works on the concept up to the mockup stage.[5]

As the design was refined, it was decided to reduce the wing's thickness substantially to increase its high speed capabilities.[7]The twin J34 engine arrangement was also swapped out for a singleWestinghouse J40engine. Only a singlehydraulicsystem was incorporated, thus measures to permit manual reversion in the event of hydraulic failure were also included.[8]Rockets also became the primary armament, which were housed in pylon-mounted pods underneath the wing. A formal operational requirement was issued by the Navy in 1948, however, according to aviation author Tommy H. Thomason, that the contract would be awarded to Douglas from the onset was an apparently foregone conclusion.[8]Specifics of this requirement included the ability to intercept and destroy an enemy aircraft at an altitude of 50,000 ft (15,240 m) within five minutes of the alarm being sounded.[9]At the time, Navy planners were particularly concerned by the threat posed to itscarrier battle groupsby high altitudeSovietbomber aircraft; furthermore, as early jet aircraft were fuel hungry and had limited endurance, to maximise an interceptor aircraft time on station the Navy desired for such an aircraft to possess a relatively high rate of climb so that it could be launched and rapidly reach its operational altitude.[10]

The XF4D-1 prototype aboardCoral Sea,in October 1953.

On account of the numerous design changes, the mockup review was delayed by almost one year, taking place in March 1949.[11]One criticism produced at this stage was that the nose-up attitude was greater than had been anticipated, necessitating changes to the aircraft's nose andradometo improve the pilot's external visibility.[11]A more pressing issue would be the J40 engine intended to power the aircraft. Douglas' design team had decided to make accommodations to facilitate the use of other engines as a contingency measure;[12]this approach proved to be quite fortunate as the J40 had a particularly troubled development, being eventually cancelled with no production units ever being delivered.[13]As a temporary measure, the prototype had to be outfitted with anAllison J35engine instead.[6]

The long-term replacement for the J40 on production aircraft was thePratt & Whitney J57,a more powerful but considerably larger engine. As the original inlet design was not a good match for the J57, it had to be redesigned.[14]The ensuing delays to the programme led to several other aircraft, such as theNorth American F-100 Super Sabreand theMikoyan-Gurevich MiG-19,beating it into operational service.[6]

During June 1954, the first flight of a production standard Skyray occurred, after which an intense period of flight testing and remedial design work followed.[12]The aft section needed to be reprofiled to eliminate undesirable buffeting as well as to reducedrag.In September 1955, initial carrier suitability trials were performed onboardUSS Ticonderoga.[12]No production aircraft were delivered until early 1956, it was declared ready for fleet introduction in April of that year.[12]A total of 419F4D-1(later designatedF-6under theunified designation system) aircraft would be produced prior to the end of production in 1958.

The Skyray was a wide delta wing design with long, sharply swept, rounded wings. It was named for its resemblance to themanta ray.[15]The thick wing roots contained the air intakes that fed its singleturbojetengine. Fuel was contained both in the wings and the deep fuselage.Leading edge slatswere fitted for increased lift during takeoff and landing while thetrailing edgescomprised mostlyelevoncontrol surfaces.[8]Additionalpitchtrimmerswere fitted inboard near the jet exhaust, and were locked upwards on takeoff and landing. It had a relatively unique design for the era, which was a key factor in the Skyray becoming one of the best-known earlyjetfighters. It was affectionately known as the "Ford" (after the "Four" and "D" of its designation).[16]During 1953,Edward H. Heinemannwas awarded theCollier Trophyin recognition of his design work on the F4D.[17]

Operational history[edit]

APQ-50A radar of an F4D-1
F4D-1 of VF(AW)-3 in flight over San Diego.

During April 1956, VC-3 became the first squadron to attain operational status with the F4D-1.[1]This unit was later redesignatedVFAW-3and assigned toNORAD,becoming the onlyUnited States Navyfighter squadron in what was predominantly aUnited States Air Force(USAF) andRoyal Canadian Air Force(RCAF) organization. VFAW-3 was permanently based atNAS North Islandin San Diego.

TheUnited States Marine Corps(USMC) also operated the Skyray. When theDepartment of Defenseadopted auniform aircraft designation systempatterned on the USAF's aircraft designation system during September 1962, the F4D was redesignated as theF-6A Skyray.TheF4D(old designation) should not be confused with theF-4D(new designation) – the latter being the "D" variant of theMcDonnell Douglas F-4 Phantom IIoperated by the USAF.[18]

The Skyray was designed exclusively for the high-altitude interception role, with a high rate and angle of climb. It set a new time-to-altitude record, flying from a standing start to 49,221 feet (15,003 m) in two minutes and 36 seconds, all while flying at a 70° pitch angle.[1]As a dedicated interceptor, the F4D was unsuited to the multi-mission capabilities that became increasingly in demand, thus the type had a relatively short career in both USN and USMC service. In addition to multiple Navy and Marine Corps squadrons, Naval Air Reserve and Marine Air Reserve squadrons VF-881, VF-882 andVMF-215also flew the Skyray. The last operational squadron wasVMF(AW)-115,which flew the Skyray until February 1964. A total of four aircraft were used for experimental purposes by theNational Advisory Committee for Aeronautics(NACA) (which was later renamedNASA) until 1969.[19]

F5D Skylancer[edit]

Main article:F5D Skylancer

The F5D Skylancer was derived from the F4D and intended to be a Mach 2 capable successor to the Skyray. Although four prototypes were built and flown, the project was cancelled as being too similar in mission parameters to theF8U Crusaderand also to reduce dependence upon Douglas Aircraft, which was also producing several other aircraft for the U.S. Navy.[19][20]This decision effectively removed Douglas from active fighter development.[21]

Variants[edit]

F4D-1 Skyray
XF4D-1
Prototypes; redesignatedYF-6Ain 1962, two built.
F4D-1
Single-seat fighter aircraft, production model; redesignatedF-6Ain 1962, 420 built.
F4D-2
Re-engined F4D-1 with the J57-F-14, 100 on order cancelled.
F4D-2N
F4D-2 version with extended nose housing twin radar scanners, project only evolved into theF5D Skylancer.

Operators[edit]

Formation of two VF-102 F4D-1 Skyrays
F4D-1 of VMF-542
United States

Aircraft on display[edit]

USMC F4D-1 BuNo 139177 from the Flying Leatherneck Aviation Museum
XF4D-1
F4D-1 (F-6A)

Specifications (F4D-1)[edit]

3-view line drawing of the Douglas F-6A Skyray
3-view line drawing of the Douglas F-6A Skyray

Data fromThe American Fighter[1]

General characteristics

Performance

  • Maximum speed:627 kn (722 mph, 1,161 km/h) at sea level
  • Range:610 nmi (700 mi, 1,130 km)
  • Ferry range:1,040 nmi (1,200 mi, 1,930 km)
  • Service ceiling:55,000 ft (17,000 m)
  • Rate of climb:18,300 ft/min (93 m/s)
  • Wing loading:41 lb/sq ft (200 kg/m2)
  • Thrust/weight:0.71

Armament

  • Guns:4 × 20 mmColt Mk 12 cannon,two on each wing just aft of the leading edge, mid-wing, underside, with 65 rounds/gun
  • Rockets:
    • 6 pods of 7 2.75 in (70 mm) unguided rocketsor
    • 4 pods of 19 2.75 in (70 mm) unguided rockets
  • Missiles:4 ×AIM-9 Sidewinderair-to-air missiles
  • Bombs:2 × 2,000 lb (907 kg) bombs

Avionics

See also[edit]

Related development

Aircraft of comparable role, configuration, and era

Related lists

References[edit]

Citations[edit]

  1. ^abcdAngelluci 1987, p. 92.
  2. ^Caygill 2006, p. 175.
  3. ^Francillon 1979, p. 480.
  4. ^Thomason 2008, pp. 129, 143.
  5. ^abThomason 2008, p. 143.
  6. ^abcCaygill 2006, p. 157.
  7. ^Thomason 2008, pp. 143-144.
  8. ^abcThomason 2008, p. 144.
  9. ^Angelluci 1987, p. 91.
  10. ^Thomason 2008, pp. 128-129, 143.
  11. ^abThomason 2008, p. 146.
  12. ^abcdThomason 2008, p. 152.
  13. ^Thomason 2008, p. 129.
  14. ^Thomason 2008, pp. 151-152.
  15. ^Gunston 1981, p. 67.
  16. ^Gunston 1981, p. 70.
  17. ^"Collier Trophy awards."Archived11 December 2008 at theWayback MachineNational Aeronautic Association.Retrieved: 27 February 2008.
  18. ^Thomason 2008, p. 266.
  19. ^abGunston 1981, p. 73.
  20. ^Thomason 2008, pp. 230-231.
  21. ^Thomason 2008, p. 262.
  22. ^Walk Around of the Skyray. A very unusual Aircraft,retrieved22 March2024
  23. ^"F4D Skyray/134748."Archived7 April 2015 at theWayback MachinePima Air and Space Museum.Retrieved: 27 January 2015.
  24. ^"F4D Skyray/134764."aerialvisuals.caRetrieved: 27 January 2015.
  25. ^"F4D Skyray/134806."Archived18 March 2015 at theWayback MachineNational Naval Aviation Museum.Retrieved: 27 January 2015.
  26. ^"Intrepid Museum Skyray."Intrepid Sea, Air & Space Museum.Retrieved: 24 April 2022.
  27. ^"F-4D Skyray/134936."Archived30 October 2013 at theWayback MachinePueblo Weisbrod Aircraft Museum.Retrieved: 29 February 2008.
  28. ^"F4D Skyray/134950."aerialvisuals.caRetrieved: 27 January 2015.
  29. ^"F4D Skyray/139177."Archived11 October 2017 at theWayback MachineFlying Leatherneck Aviation Museum.Retrieved: 27 January 2015.
  30. ^Lednicer, David."The Incomplete Guide to Airfoil Usage".m-selig.ae.illinois.edu.Retrieved16 April2019.

Bibliography[edit]

External links[edit]

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