The date was 16 April 1956. The place was Naval Air Station (NAS) North Island in San Diego. Then and there, US Navy Composite Squadron THREE (VC-3) Blue Nemesis became the first Navy squadron to achieve operational status with a sensational new bat-winged jet fighter- the Douglas F4D-1 Skyray or Ford. The new jet would go on to become the first carrier-based aircraft to hold a world absolute speed record (752.944 miles per hour) and the first such aircraft capable of exceeding the sound barrier (Mach 1) in level flight. How the Skyray got there is the meat of the story.
Two Douglas aerodynamicists, Gene Root and Apollo M.O. “Amo” Smith, went to Paris to assess aerodynamic data captured from the Germans after their surrender in 1945. The two men found the wind-tunnel test data obtained from several tailless German prototypes along with the Messerschmitt Me-163 Komet rocket-powered interceptor. Root and Smith also discussed designs with Dr. Alexander Lippisch, the man behind the Komet and many of the German delta wing and tailless designs. Lippisch had reportedly been influenced by Indonesian zanonia seeds.
After returning to the States, Root and Smith began working on a delta-winged interceptor. When in 1947 the Navy Bureau of Aeronautics (BuAer) request for a short-range high-altitude carrier-based interceptor, Douglas leveraged the recent delta wing research to quickly draw the D-571. Teaming with renowned Douglas designers Ed Heinemann and R.G. Smith, the D-571 was redrawn as the D-571-4 for the BuAer request. BuAer issued a contract for two prototypes under the designation XF4D-1. All it took was one look at the wing planform of the jet to hang the name Skyray on it.
The prototypes were built under a curtain of unusual secrecy, including screening of information released to the public about the program. In October 1950 the first XF4D-1 prototype was rolled out. The jet wasn’t a flying wing. It wasn’t a true delta wing either. People said it looked like a valentine heart or even the ace of spades. The XF4D-1 had no horizontal tail so pitch was controlled with hydraulically-boosted elevons on the trailing edge of the wing. In the event of a hydraulic system failure, the control stick could be extended so the pilot had the additional leverage needed to wrestle the system.
Other design characteristics included thick wing roots containing engine air intakes combined in the fuselage to provide air for a single turbojet engine. Splitter plates were fitted to production aircraft to reduce turbulence down the intakes. Both wings and the fuselage contained fuel. The wings, swept at 52.5 degrees, were fitted with leading edge slats to provide additional life at low speeds. Pitch trimmers and air brakes were mounted inboard close to the engine exhaust. The pitch trimmers were normally locked in the full up position on takeoff and landing. Wings were capable of folding for carrier storage. The engine initially chosen for the Skyray was the ill-fated Westinghouse J40. Thankfully, unlike the McDonnell F3H Demon, the F4D design had enough room to accommodate the larger, more powerful, and far more reliable Pratt & Whitney J57 engine- various versions of which powered the 421 Skyrays built by Douglas at their plant in El Segundo, California.
The Skyray was armed with four Colt M12 20 millimeter cannons, but these were often removed and the gun ports covered. The jet was equipped with the AN/APQ-50A search/single-track radar tied to an Aero 13F fire control system. Under the jet were three pylons on each wing and a centerline pylon. Total maximum external load was 4,000 pounds. Two 300 gallon drop tanks were often carried on the middle wing pylons. Though capable of carrying bombs and other air-to-ground ordnance, Skyrays weren’t usually so loaded. Fords did often carry Raytheon AAM-N-7 Sidewinder heat seeking air-to- air missiles. The F4D-1 was not equipped with an internal refueling probe, though the jet was capable of carrying external tanks with refueling probes attached to them. Later in their careers, Skyrays were also fitted with a spool for towing a target sleeve or dart-style tow target.
After the prototypes were trucked out to the site, Douglas test pilot Larry Peyton flew Allison J35-A-17-powered XF4D-1 prototype number 1 for the first time from Edwards Air Force Base (AFB) on 23 January 1951. Peyton reported a tendency for the Skyray to pitch up with trim unable to resolve it and overall handing to be suspect. It mostly boiled down to inertial coupling, a new phenomenon to Douglas but experienced during the development of the North American F-100 Super Sabre. Weight distribution- the heavy engine in the tail and swept wings, contributed to the problem. The surprising thing is that the tendency was never really engineered out of the design. Pilots were trained how to recover instead, even resorting to liberal use of placards in the cockpit to remind them of handling/speed restrictions. But the handling qualities of the jet were soon seen as an advantage rather than a weakness.
Testing and evaluation continued. In 1952, the Skyray, quickly and inevitably nicknamed the Ford, was evaluated by several Navy and Marine Corps pilots at Edwards AFB. They pilots were fully briefed about the tendencies of the aircraft but when they flew it they liked its positives more than feared its foibles. Of note was their unanimous impression that the jet, at least in part due to its inherent instability, would out-turn anything in the air. The story goes that Marine Corps Major Marion Carl flew the jet and went on record as saying if the Corps had the Skyray in Korea they’d be consistently scoring MiG kills with it.
The second prototype XF4D-1 was being checked out at the Naval Air Test Center (NATC) at NAS Patuxent River in Maryland while prototype number 1 was being tested at Edwards. In December of 1953, Douglas engineer Ed Heinemann was awarded the Collier Trophy in recognition of his design work on the F4D Skyray. Heinemann shared the honors for the first supersonic fighter with Hames H. “Dutch” Kindleberger of North American Aviation for their also-supersonic F-100 Super Sabre. Even though the accolades were there, it took several more years and the development of the J57 engine-powered version of the aircraft until the first F4D-1 was delivered to VC-3. Production of the F4D-1 began in 1954.
Three months after gaining operational status, VC-3 was redesignated as All Weather Fighter Squadron THREE VF(AW)-3. The Blue Nemesis then became the only Navy squadron assigned to the US Air Force North American Air Defense Command (NORAD), normally consisting of US Air Force and Royal Canadian Air Force (RCAF) units. Less than a year after VC-3 received their first F4D-1s, Marine Corps Fighter Squadron VMF-115 Able Eagles became the first Leatherneck Ford fliers. VF-74 Bedevilers were the first Navy squadron to deploy with the Ford, going to sea with Carrier Air Group SIX (CVG-6) aboard the Essex-class carrier USS Intrepid (CVA-11) in February of 1959.
A Skyray set a world time-to-climb record of 2 minutes 36.05 seconds to reach an altitude of 49,213 feet from a standing start in 1958. The first delta-winged aircraft to reach supersonic speeds, the F4D-1 rewrote many of the closed-course speed records at Edwards later that year. Fords would go on to equip thirteen Navy and eight Marine Corps fighter squadrons. When the aircraft designation system was re-swizzled in 1962 the F4D-1 Skyray was redesignated the F-6A Skyray. But as a dedicated supersonic high-altitude interceptor with no multi-mission capabilities soon expected of Naval and Marine Corps carrier-based aircraft, the career of the Ford was short.
The beginning of the McDonnell-Douglas F-4H Phantom II was in essence the end for the Skyray. A true one-trick pony, the Ford was phasing out of service in many cases after only six or seven years of operational use. Marine Corps squadron VMF(AW)-542 Tigers were the last active-duty squadron to fly the Skyray. VC-3 Blue Nemesis ceremonially retired the last operational Skyrays in the fleet on 16 October 1964. The National Advisory Committee for Aeronautics (NACA) and later the National Aeronautics and Space Administration (NASA) used four F-6As for testing until 1969. The Skyray was the last fighter aircraft designed and produced by Douglas before their merger with McDonnell, thereafter known as McDonnell-Douglas.
This Skyray operating procedures training film from 1956 was uploaded to YouTube by Raymond Norton.