Hudson Air Depot- Douglas F4D-1 Skyray 134836

As World War II drew to a close the Allies began gathering information on Nazi Germany’s weapons programs. As part of this quest for information the US Army conducted Operation Paperclip, which enlisted and brought to America up to 1,600 scientists, technicians and engineers, among them Werner Von Braun and Alexander Lippisch. Werner Von Braun is regarded as the preeminent rocket engineer of the 20th century. Lippisch was a preeminent proponent of delta-winged tailless aircraft, his most famous design being the Messerschmitt Me-163 Komet. After the war Lippisch’s work was found to be very interesting to the US military. Using Lippisch, research the US Air Force, in cooperation with Convair, developed the XF-92 delta winged rocket powered research vehicle . Only one XF-92A turbojet powered aircraft was built, however the experience led Convair to design and develop the F-102 Delta Dagger, F-106 Delta Dart and the B-58 Hustler.

In 1947 The US Navy contracted with Douglas Aircraft Corporation to build a short range interceptor using a delta winged configuration. Douglas had done some design studies earlier in the 1930s when Jack Northrop’s Northrop Aircraft Division was a part of the company. Since that time Douglas had been kept busy with more conventional designs. Later, in May 1945 , two Douglas aerodynamacists had travelled to Europe and applied information from Lippisch to their own data on tailless aircraft. Once the Navy contract was in place the design took on the Douglas Project number D-571. D-571 started out as a true flying wing but as wind tunnel tests progressed the wing designed thinned out and the fuselage was enlarged to become a more conventional modified thin delta wing design, this final design number was D-571-4. It had a gross weight of 15,700 llbs., and a wing area of 676 sq. ft. It was intended that the new interceptor would use the Westinghouse XJ40 turbojet which was still in devlopment.

In December of 1949 the Navy’s Bureau of Aeronautics issued a contract for two prototypes of the D-571-4, now known as the XF4D-1, with an overall length of 44 ft, a wingspan of 36 ft. 6 in., and a wing area of 557 sq. ft. There were two 320 gallon fuel tanks buried in the fuselage which only allowed for 45 minutes of flight time. This was deemed sufficient for the aircraft’s intended role of a point interceptor. Because Westinghouse was having trouble with the J40 engine Douglas’ chief designer, Ed Heinemann, insisted that the fuselage be made large enough for the J57 engine in case it was decided to use this engine at a later date. Because the J40 was still having development problems both prototypes were built using the Allison J35 engine which produced 5,000 lbs. of thrust as compared to the anticipated Westinghouse J40’s 7,500 lbs. thrust rating.

On the morning of January 21, 1951 Douglas test pilot Larry Peyton took Douglas XF4D-1 Skyray, buaer # 124586, on its maiden flight at Edwards Air Force Base. The aircraft was painted overall glossy sea blue with a red stripe outlined in white with the name “Skyray” on the nose which reflected its striking resemblance to the Manta ray. It is no surprise that the underpowered prototype had difficulty achieving reaching Mach1 except in a dive even though the design was supposed to be capable of exceeding the speed of sound at ground level. During this time several attempts were made to solve a persistent problem with rudder oscillations. However, preliminary evaluations on the design and spin testing were conducted using the second prototype BuAer # 124587 while the first prototype was being re-engined with the XJ-40 engine which was still only producing 6,000 Lbs. of thrust. Flights with the new engine between July 16 to July 24 1952 proved disappointing and due to continuing rudder oscillations a Mach number of 0.96 was all that could be achieved. Eventually modifications to the tail allowed the F4D to exceed the speed of sound in level flight. In July 1953 at Naval Air Test Center Patuxent River, Maryland field catapult and field arrested landing test were conducted. Carrier suitability trials were conducted on board CVA-42 USS Coral Sea in October,1953. Although over 20 recommendations were made the aircraft was deemed suitable for carrier operations.

Even though the Skyray’s teething problems persisited it was still a very fast aircraft. On October 3, 1953, LtCdr. James Verdin took a streamlined, lightened XF4D-1 over a straight 3KM course to a set a new world’s absolute speed record of 753.4 MPH. Two weeks later a new 100 KM closed course record of 728.1 MPH was set by Douglas’ test pilot Robert Rahn. A later J-57 equipped version set 5 time to altitude records in May, 1958.

Due to continuing problems with the Westinghouse J40 engine the decision was made to eguip production Skyrays with the Pratt & Whitney J57 engine, variants of which were capable of producing 10,500 Lbs. of thrust, 16,000 Lbs. with afterburner. Over 80% of the airframe needed to be redesigned to accommodate the new engine. The first flight of a J-57 equipped F4D Skyray took place on June 5, 1954. During this flight Mach 1 was easily passed. One more delay was encountered when modifications were needed to the inlet duct.

Skyrays did not reach the fleet until 1956, eventually equiping 11 squadrons for the Navy and 7 squadrons for the Marines. By February, 1964 the F4D was phased out of frontline service in favor of the Vought F8U Crusader. In 1962, under the Defense Department’s new designation system, the F4D-1 Skyray was renumbered as the F-6A Skyray. The Test Pilot School at Patuxent River continued to use examples until November 25, 1969 when the last flyable Skyray (134806) was ferried to NAS Pensacola, Florida where it is on exhibit at the National Naval Aviation Museum.

Production Skyrays had a maximum speed of 722 at sea level, an initial climb rate of 18,300 feet/minute, service ceiling of 55,000 feet with a combat ceiling of 51,000 feet. Armament consisted of 4 20mm cannon and was most often equiped with 4 Aim-9 Sidewinder air to air missles and/or 300 gallon drop tanks and an centerline electronics pod. It could also carry 6 pods of 7 x 2.75 in.unguided rockets or 4 pods of 19 x 2.75 in unguided rockets or 2 2,000 lb. Bombs.

A testimony to the Skyray’s ability as an point interceptor is that it is the only US Navy aircraft to have served with the NORAD, the North American Aerospace Defense Command. Normally frontline US and Canadian Air Force fighters serve with this agency.

As a subject for this model I chose the Douglas F4D-1 Skyray ,BuAer #134836, that is on display at the New England Air Museum in Windsor Locks, CT. Of the 421 Skyrays built, 2 prototypes & 419 production, this aircraft is the 106th aircraft built. The paint scheme is representative of an aircraft of VF-162 “The Hunters” although I believe the dark blue color of the elevons and rudder is incorrect. The squadron was commisioned at NAS Cecil Field, Florida on September 1, 1960 the first aircraft did not arrive until a month later on October 10th. Naval Fighters #13 Douglas F4D Skyrays states “At this time VF-162 Skyrays carried CVG-16’s modex ‘AH’, a ‘200’ series nose number, and an elaborate marking scheme consisting of black upper elevon and rudder surfaces with gold stars of various sizes scattered randomly about.” There is a picture in this book showing 134836 in flight on February 2, 1961 on page 134.

To represent this aircraft I used Tamiya kit # 61055 Douglas F4D-1 Skyray. It was built straight out of the box with the exception of the paint scheme and the removal of the refueling probe from the left hand external fuel tank.

In addition to the decals supplied with the kit decal sheets used for this model were:

Eagle Strike # 48048A US 45 Degree ID Numbers & Letters (Black)

Super Scale International # 72-657 F3H-2 Demons VF-41 CAG, VF-161

Experts-Choice # CF-6 Metallic Gold Film

AeroMaster # 48-541 F4D-1 Skyrays Part 1

Testors Model Master paints were used throughout this kit.

Bibliography:

Naval Fighters Number Thirteen – Douglas F4D Skray By Nick Williams and Steve Ginter Published by Steve Ginter

ISBN 0-942612-13-2

U.S. Naval Fighters, Author Lloyd S. Jones, Aero Publishers, Inc. ISBN 0-8168-9254-7

U.S. Fighters, Author Lloyd S. Jones, Aero Publishers, Inc. ISBN 0-8168-9200-8

Combat Aircraft of the World, Edited and Compiled by John W.R. Taylor, published by G.P. Putnam’s Sons, SBN 425-03633-2