Douglas Skyrocket D-558-II

In this configuration, NACA research pilot [Vous devez être inscrit et connecté pour voir ce lien] flew the aircraft only once for familiarization on 17 September 1956.

The 123 flights of NACA 143 served to validate wind-tunnel predictions of the aircraft's performance, except for the
fact that the aircraft experienced less drag above Mach 0.85 than the wind tunnels had indicated.

NACA 144 also began its flight program with a turbojet powerplant. NACA pilots [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] flew 21 times in this configuration to test airspeed calibrations and to research longitudinal and lateral stability and control.

In the process, during August 1949 they encountered pitch-up problems, which NACA engineers recognized as serious because they could produce a limiting and dangerous restriction on flight performance.

Hence, they determined to make a complete investigation of the problem.

In 1950, Douglas replaced the turbojet with an LR-8 rocket engine, and its pilot, [Vous devez être inscrit et connecté pour voir ce lien], flew the aircraft seven times up to a speed of Mach 1.88 (1.88 times the speed of sound) and an altitude of 79,494 ft (24,230 m), the latter an unofficial world's altitude record at the time, achieved on 15 August 1951.

In the rocket configuration, a Navy P2B (Navy version of the [Vous devez être inscrit et connecté pour voir ce lien]) launched the aircraft at approximately 30,000 feet (9,000 m) after taking off from the ground with the Skyrocket attached beneath its bomb bay.

During Bridgeman's supersonic flights, he encountered a violent rolling motion known as lateral instability that was less pronounced on the Mach 1.88 flight on 7 August 1951, than on a Mach 1.85 flight in June when he pushed over to a
low angle of attack (angle of the fuselage or wing to the prevailing wind direction).

The NACA engineers studied the behavior of the aircraft before beginning their own flight research in the aircraft in September 1951.

Over the next couple of years, NACA pilot [Vous devez être inscrit et connecté pour voir ce lien] flew the aircraft 20 times to gather data on longitudinal and lateral stability and control, wing and tail loads, and lift, drag, and buffeting characteristics at speeds up to Mach 1.878.

US Navy BuNo 37974 - NACA #144

[Vous devez être inscrit et connecté pour voir cette image]

At that point, Marine Lt. Col. [Vous devez être inscrit et connecté pour voir ce lien] flew the aircraft to a new (unofficial) altitude record of 83,235 feet (25,370 m) on 21 August 1953, and to a maximum speed of Mach 1.728.

Following Carl's completion of these flights for the Navy, NACA technicians at the High-Speed Flight Research Station (HSFRS) near [Vous devez être inscrit et connecté pour voir ce lien], California, outfitted the LR-8 engine's combustion chambers with nozzle extensions to prevent the exhaust gas from affecting the rudders at supersonic speeds.

This addition also increased the engine's thrust by 6.5 percent at Mach 1.7 and 70,000 feet (21,300 m).

Even before Marion Carl had flown the Skyrocket, HSFRS Chief Walter C. Williams had petitioned NACA headquarters unsuccessfully to fly the aircraft to Mach 2 to garner the research data at that speed.

Finally, after Crossfield had secured the agreement of the Navy's Bureau of Aeronautics, NACA director [Vous devez être inscrit et connecté pour voir ce lien] relaxed the organization's usual practice of leaving record setting to others and consented to attempting a flight to Mach 2.

In addition to adding the nozzle extensions, the NACA flight team at the HSFRS chilled the fuel (alcohol) so more could be poured into the tank and waxed the fuselage to reduce drag.

With these preparations and employing a flight plan devised by project engineer Herman O. Ankenbruck to fly to approximately 72,000 feet (21,900 m) and push over into a slight dive, Crossfield made aviation history on 20 November 1953, when he flew to Mach 2.005, 1,291 miles per hour (2,078 km/h).

He became the first pilot to reach Mach 2 in this, the only flight in which the Skyrocket flew that fast.

Following this flight, Crossfield and NACA pilots [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] flew the aircraft for such purposes as to gather data on pressure distribution, structural loads, and structural heating, with the last flight in the program occurring on 20 December 1956, when McKay obtained dynamic stability data and sound-pressure levels at transonic
speeds and above.

Meanwhile, NACA 145 had completed 21 contractor flights by Douglas pilots [Vous devez être inscrit et connecté pour voir ce lien] and William Bridgeman in November 1950.

In this jet-and-rocket-propelled craft, Scott Crossfield and Walter Jones began the NACA's investigation of pitch-up lasting from September 1951 well into summer 1953.

They flew the Skyrocket with a variety of wing-fence, wing-slat and leading edge chord extension configurations, performing various maneuvers as well as straight-and-level flying at transonic speeds.

While fences significantly aided recovery from pitch-up conditions, leading edge chord extensions did not, disproving wind-tunnel tests to the contrary. Slats (long, narrow auxiliary airfoils) in the fully open position eliminated pitch-up except in the speed range around Mach 0.8 to 0.85.

In June 1954, Crossfield began an investigation of the effects of external stores (bomb shapes and fuel tanks) upon the aircraft's transonic behavior. McKay and [Vous devez être inscrit et connecté pour voir ce lien] completed the NACA's investigation of this issue, with
McKay flying the final mission on 28 August 1956.

Besides setting several records, the Skyrocket pilots had gathered important data and understanding about what would and would not work to provide stable, controlled flight of a swept-wing aircraft in the transonic and supersonic flight regimes.

The data they gathered also helped to enable a better correlation of wind-tunnel test results with actual flight values, enhancing the abilities of designers to produce more capable aircraft for the armed services, especially those with
swept wings.