Westinghouse had not yet delivered the J40 engine specified by the Navy, but with deadlines looming, Douglas jury-rigged the prototypes with Allison J35-A-17s, which left the airplanes sorely underpowered. In the fall of 1950, the prototypes were trucked to Edwards Air Force Base in California to see if they were more than just a pair of pretty faces.
First flight, and the harbinger of what the Chinese would call interesting times, came on the morning of January 21, 1951. Douglas test pilot Larry Peyton, whose experience was mainly in transports, was chosen for this run. The airplane was to be flown on manual controls to determine some of the nuances of takeoff trim. Then, after some light maneuvering, back it would come to the lake bed. Piece of cake.
Peyton lifted off at 140 mph for what he intended to be a gradual climb to 10,000 feet. The Skyray had other ideas. As speed increased, so did nose-up pitch, even with the stick pressed against the instrument panel. When Peyton hit the trimmers, the nose pitched sharply down, and pulling the stick all the way back had no effect. Another try with the trimmers and the Skyray flared and mushed back to earth.
With the vast Edwards lake bed largely ahead of him, Peyton stayed with it, lifting off again. He brought the Ford into a steady climb at 160 mph—with the stick full forward. After a few test maneuvers, he turned for home and fluttered to the ground, fighting the weird pitch behavior. He never flew the Skyray again.
Another Douglas test pilot, Russell Thaw, took up the preliminary work of fixing the trim problems on takeoff. Then the Skyray passed to Robert Rahn, a top hand among the experimental test pilots. He had flown Spitfires with the Army Air Forces during World War II, and had since tested a host of aircraft types for Douglas.
Having seen Thaw’s flights, Rahn was not sure he wanted to fly the XF4D, but in October 1951, he tried it on. “I flew on manual flight control and quickly learned why Larry wanted no part of the Skyray,” he wrote in his memoir, Tempting Fate. “The stick forces were exorbitant for the small control-surface deflection achieved. The plane was tough to handle unless below 200 knots and in smooth air—not a good sign for a fighter which may have to make an approach onto the pitching deck of an aircraft carrier at night.”
Still, the Skyray’s potentially breathtaking performance, maneuverability at altitude, and the forgiving qualities of that huge wing found a spot in Rahn’s affections. “This aircraft,” he wrote, “was just what I had been looking for in a fighter since my flying days in the Spitfire. The F4D was a fighter pilot’s dream.” As Rahn would soon learn, it could also be a fighter pilot’s nightmare.
“The Skyray,” says Mal Abzug, “was the first Douglas airplane to have the phenomenon known as inertial coupling, in which the airplane goes out of control at high roll rates. It’s caused by the way the weight is distributed. Ever since airplanes were made with the swept wings, they’ve all had that property. First airplane was the F-100. We had a problem about the same time, around 1950. The Skyray was one of the pioneering airplanes in this area.”
Fighter aircraft are required to be able to enter and recover from spins, defined as uncontrolled rotations around any axis of a fully stalled airplane. Conventional recovery is a simple matter of applying opposite rudder to stop the rotation and moving the stick forward to get the nose down and restore airflow over the wing. The Skyray evidently thought this was too easy.