posted on Feb, 1 2007 @ 11:25 AM
The F8U-3, was powered by a Pratt & Whitney J75-P-6 engine that provided over 26,000 pounds of thrust, it could attain speeds in the Mach 2 range.
There was a scoop on the lower lip of the inlet to properly align the shock wave at high speed. There were also manual-control bypass doors to bleed
excess air overboard so as to prevent inlet choking at supersonic speeds. Although the J58-P-2 was the intended powerplant for an operational version
of the plane, I think structural limitations would have prohibited Mach 3 flight.
After the 1957/1958 fly-off competition was lost to the F4H, two Super Crusaders were made available to NASA for research purposes. These airplanes
had speed and altitude performance that made them ideal for investigating sonic booms effects at altitudes up to 60,000 feet.
Bill Alford and Don Mallick shared flying duty in the NASA F8U-3 program at Langley Research Center, Virginia. Training was provided by Vought chief
test pilot John Conrad. The first aircraft arrived at Langley on 26 May 1959. It served as the primary flight-test aircraft. The second arrived a
month later and was mostly used for spare parts.
Mallick descibed his first flight in the F8U-3 as follows:
"On my first takeoff, I rotated the nose and was immediately airborne. As per the briefing, I quickly moved the landing gear handle up and rotated
the nose even higher in pitch attitude to keep from exceeding the maximum gear-extended speed. As the gear went up and the movable rear ventrals went
down, the aircraft wallowed a little. I had discussed this anomalous motion with John Conrad prior to flight and it came as no surprise. I was
surprised, however, that the aircraft had a distinct sideslip. A post-flight discussion with John later revealed that the afterburner nozzle on this
aircraft actually distorted from a circle to a slight oval when the afterburner was lit, and the thrust vector was slightly misaligned with the
aircraft's center of gravity. This undesirable characteristic only manifested at lower speeds, such as takeoff with the afterburner engaged. At
higher speeds, the effect was scarcely noticeable. The F8U-3 had excellent handling qualities. It had light and comfortable control forces, as a
fighter should, and there was no tendency to over-control or cause pilot-induced oscillation (PIO) in any of the three axes of control."
The inlet was manually controlled and adjusted with regard to Mach number. The bypass doors opened at about Mach 1.4, accompanied by an increase in
thrust. They bled excess air overboard to allow the engine and inlet to operate more efficiently by converting the inlet air's velocity to pressure.
The pilot, however, could not adjust the thrust during afterburner operation. It was either in full afterburner or no afterburner, with no setting in
between. The F8U-3 also had a problem with compressor stalls.
The pilot’s windscreen was made of Plexiglas like the rest of the canopy. This limited cruise time at Mach 2. High-speed airflow easily heated the
thin plastic material, structurally weakening it. After 10 minutes, its reduced strength left it vulnerable to catastrophic failure. The NASA test
conductors therefore set a five-minute limit on cruise at Mach 2.