Tuesday, October 27, 2009

Douglas Skyrocket (D-558-2 or D-558-II


The Douglas Skyrocket (D-558-2 or D-558-II) was a rocket and jet-powered supersonic research aircraft built by the Douglas Aircraft Company for the United States Navy. On 20 November 1953, shortly before the 50th anniversary of powered flight, Scott Crossfield piloted the Douglas D-558-2 Skyrocket to Mach 2, or more than 1,290 mph (2076 km/h), the first time an aircraft had exceeded twice the speed of sound.

The "-2" in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program. The phase-one aircraft, the D-558-1, was jet powered and had straight wings. The third phase, which never came to fruition, would have involved constructing a mock-up of a combat type aircraft embodying the results from the testing of the phase one and two aircraft. The eventual D-558-3 design, which was never built, was for a hypersonic aircraft similar to the North American X-15.[1].

When it became obvious that the D558-1 fuselage could not be modified to accommodate both rocket and jet power, the D558-2 was conceived as an entirely different aircraft[2]. A contract change order was issued on 27 January 1947 to formally drop the final three D558-1 aircraft and substitute three new D558-2 aircraft instead[3].

The Skyrocket featured wings with a 35-degree sweep and horizontal stabilizers with 40-degree sweep. The wings and empennage were fabricated from aluminum and the large fuselage was of primarily magnesium construction. The Skyrocket was powered by a Westinghouse J34-40 turbojet engine fed through side intakes in the forward fuselage. This engine was intended for takeoff, climb and landing. For high speed flight, a four-chamber Reaction Motors LR8-RM-6 engine (the Navy designation for the Air Force's XLR-11 used in the Bell X-1), was fitted. This engine was rated at 6,000 lbf (27 kN) static thrust at sea level. A total of 250 gallons (946 liters) of aviation fuel, 195 gallons of alcohol, and 180 gallons of liquid oxygen were carried in fuselage tanks.

The Skyrocket was configured with a flush cockpit canopy, but visibility from the cockpit was poor, so it was re-configured with a raised cockpit with conventional angled windows. This resulted in a greater profile area at the front of the aircraft, which was balanced by an additional 14 inches (36 cm) of height added to the vertical stabilizer. Like its predecessor, the D558-1, the D558-2 was designed so that the forward fuselage, including cockpit, could be separated from the rest of the aircraft in an emergency. Once the forward fuselage had decelerated sufficiently, the pilot would then be able to escape from the cockpit by parachute.

General characteristics
  • Crew: one pilot
  • Length: 42 ft 0 in (12.8 m)
  • Wingspan: 25 ft 0 in (7.6 m)
  • Height: 22 ft 8 in (3.8 m)
  • Wing area: 175 ft² (16.2 m²)
  • Empty weight: 9,421 lb (4,273 kg)
  • Max takeoff weight: 15,266 lb (6,923 kg)
  • Powerplant:
    • 1× Westinghouse J34-WE-40 turbojet, 3,000 lbf (13 kN)
    • 1× Reaction Motors XLR-8-RM-5 rocket engine, 6,000 lbf (27 kN)
Performance
  • Maximum speed: 720 mph, 1,250 mph when air-launched (1,160 km/h, 2,010 km/h when air-launched)
  • Stall speed: 160.1 mph (257.7 km/h)
  • Service ceiling: 16,500 ft (5,030 m)
  • Rate of climb: 22,400 ft/min, 11,100 ft/min under rocket power only (6,830 m/min., 3,380 m/min under rocket power only)
  • Wing loading: 87.2 lb/ft² (426 kg/m²)
  • Thrust/weight (jet): 0.39

No comments:

Post a Comment