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D-558-2 Skyrocket Douglas
D-558-2 Skyrocket
High-Speed Research Aircraft

DESCRIPTION:
When the US Navy Bureau of Aeronautics and NACA agreed to develop the D-558-1 Skystreak transonic research plane, they envisioned later replacing the design's single large turbojet with a smaller turbojet and a rocket motor to explore flight at supersonic speeds. However, review of German aerodynamic data captured at the end of World War II convinced planners and designers that the basic design should also be used to investigate the use of swept-wings. The German research and NACA wind-tunnel tests had confirmed that swept-wings offer many advantages in high-speed flight, especially raising the critical Mach number to reduce the effect of wave drag. Based on these findings, Douglas designed a completely new aircraft, the D-558-2 Skyrocket, with a larger diameter fuselage containing a turbojet for takeoff and low-speed flight as well as a rocket engine for high-speed flight. The new design also featured a mid-set wing with 35° of sweep and a swept horizontal tail assembly.
Three examples of the D-558-2 were built, the first flying in 1948. This first example was powered by a turbojet only, because of slow development of the XLR-8 rocket motor, and was only capable of conventional takeoffs and landings. The second example, D-558-2 #2, was the first and only to feature the mixed powerplant and was also intended for conventional takeoffs, but was later modified to be carried aloft by a B-29 mothership and launched in flight. The #2 ship later had its turbojet deleted in favor of rocket-only propulsion, and the extra space was used for additional fuel. In this configuration, the aircraft was able to achieve Mach 2.005 at 62,000 ft (18,915 m) on 20 November 1953, thereby becoming the first aircraft to exceed Mach 2. Probably the most successful of the series, the #2 ship also set an unofficial altitide record of 83,235 ft (25,395 m) on 21 August 1953.
Although overshadowed by the X-1, the Skyrocket was an exceptionally successful program that provided a great deal of useful data on supersonic flight. In particular, the D-558-2 uncovered the tendency of swept-wings to pitch-up in certain conditions and was used to explore the effects of a number of aerodynamic devices at supersonic speeds. Over 200 flights were made before the Skyrocket was retired in December 1956.
Last modified 27 September 2009

HISTORY:

First Flight 4 February 1948

CREW: one: pilot

ESTIMATED COST:

unknown

AIRFOIL SECTIONS:

Wing Root NACA 63-010

Wing Tip

NACA 63-012

DIMENSIONS:

Length 45.25 ft (13.79 m)

Wingspan 25.00 ft (7.62 m)

Height 11.50 ft (3.51 m)

Wing Area 175.0 ft² (16.26 m²)

Canard Area

not applicable

WEIGHTS:

Empty unknown

Normal Takeoff unknown

Max Takeoff (turbojet only) 10,570 lb (4,795 kg)
(mixed) 15,265 lb (6,925 kg)
(rocket only) 15,785 lb (7,170 kg)

Fuel Capacity internal: unknown
external: unknown

Max Payload

unknown

PROPULSION:

Powerplant one Westinghouse J34-22 turbojet and
one Reaction Motors XLR-8-5 rocket motor

Thrust (J34-22) 3,000 lb (13.35 kN)
(XLR-8) 6,000 lb (26.69 kN)

PERFORMANCE:

Max Level Speed at altitude: 585 mph (940 km/h) at 20,000 ft (6,095 m) [turbojet only]
at altitude: 720 mph (1,160 km/h) at 40,000 ft (12,190 m) [mixed, conventional takeoff]
at altitude: 1,250 mph (2,010 km/h) at 67,500 ft (20,575 m) [rocket only, air-launched]
at sea level: unknown

Initial Climb Rate unknown

Service Ceiling unknown

Range unknown

g-Limits unknown

KNOWN VARIANTS:

D-558-2 #1 First example built and flown, initially powered by only a turbojet until rocket motors became available, used mainly by the US Navy

D-558-2 #2 Second example, used by NACA primarily to study the characteristics of swept-wings, only aircraft of the series to have mixed turbojet and rocket propulsion but was later modified to a rocket only configuration and air-launched from a B-29 mothership, set several speed and altitude records, now on display at the National Air & Space Museum

D-558-2 #3 Final aircraft built and powered by rocket motor only, also modified for air-launch only, used by NACA to explore the effectiveness of wing slats and leading edge devices as well as aerodynamic effects on under-wing stores at high-speeds

D-558-3 Proposed hypersonic research aircraft derived from the D-558-2, intended to reach Mach 9 at 750,000 ft (228,600 m) but was abandoned in favor of the X-15

KNOWN OPERATORS:

United States (US Navy)
United States (NACA)

3-VIEW SCHEMATIC:

D-558-2 Skyrocket

SOURCES:

Aviation Enthusiasts Corner D-558-2 site

Chant, Christopher and Taylor, Michael J.H. The World's Greatest Aircraft. Edison, NJ: Chartwell Books, 2006, p. 282, Douglas D-558-1 Skystreak and D-558-2 Skyrocket.

Donald, David, ed. The Complete Encyclopedia of World Aircraft. NY: Barnes & Noble, 1997, p. 356, Douglas D-558-2 Skyrocket.

NASA Dryden Research Center D-558-2 site

National Air & Space Museum D-558 site

Winchester, Jim. Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. San Diego, CA: Thunder Bay Press, 2005, p. 86-87, Douglas D-558 Skystreak/Skyrocket.

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DESCRIPTION: When the US Navy Bureau of Aeronautics and NACA agreed to develop the D-558-1 Skystreak transonic research plane, they envisioned later replacing the design's single large turbojet with a smaller turbojet and a rocket motor to explore flight at supersonic speeds. However, review of German aerodynamic data captured at the end of World War II convinced planners and designers that the basic design should also be used to investigate the use of swept-wings. The German research and NACA wind-tunnel tests had confirmed that swept-wings offer many advantages in high-speed flight, especially raising the critical Mach number to reduce the effect of wave drag. Based on these findings, Douglas designed a completely new aircraft, the D-558-2 Skyrocket, with a larger diameter fuselage containing a turbojet for takeoff and low-speed flight as well as a rocket engine for high-speed flight. The new design also featured a mid-set wing with 35° of sweep and a swept horizontal tail assembly. Three examples of the D-558-2 were built, the first flying in 1948. This first example was powered by a turbojet only, because of slow development of the XLR-8 rocket motor, and was only capable of conventional takeoffs and landings. The second example, D-558-2 #2, was the first and only to feature the mixed powerplant and was also intended for conventional takeoffs, but was later modified to be carried aloft by a B-29 mothership and launched in flight. The #2 ship later had its turbojet deleted in favor of rocket-only propulsion, and the extra space was used for additional fuel. In this configuration, the aircraft was able to achieve Mach 2.005 at 62,000 ft (18,915 m) on 20 November 1953, thereby becoming the first aircraft to exceed Mach 2. Probably the most successful of the series, the #2 ship also set an unofficial altitide record of 83,235 ft (25,395 m) on 21 August 1953. Although overshadowed by the X-1, the Skyrocket was an exceptionally successful program that provided a great deal of useful data on supersonic flight. In particular, the D-558-2 uncovered the tendency of swept-wings to pitch-up in certain conditions and was used to explore the effects of a number of aerodynamic devices at supersonic speeds. Over 200 flights were made before the Skyrocket was retired in December 1956. Last modified 27 September 2009
HISTORY:
First Flight	4 February 1948
CREW:	one: pilot
ESTIMATED COST:	unknown
AIRFOIL SECTIONS:
Wing Root	NACA 63-010
Wing Tip	NACA 63-012
DIMENSIONS:
Length	45.25 ft (13.79 m)
Wingspan	25.00 ft (7.62 m)
Height	11.50 ft (3.51 m)
Wing Area	175.0 ft² (16.26 m²)
Canard Area	not applicable
WEIGHTS:
Empty	unknown
Normal Takeoff	unknown
Max Takeoff	(turbojet only) 10,570 lb (4,795 kg) (mixed) 15,265 lb (6,925 kg) (rocket only) 15,785 lb (7,170 kg)
Fuel Capacity	internal: unknown external: unknown
Max Payload	unknown
PROPULSION:
Powerplant	one Westinghouse J34-22 turbojet and one Reaction Motors XLR-8-5 rocket motor
Thrust	(J34-22) 3,000 lb (13.35 kN) (XLR-8) 6,000 lb (26.69 kN)
PERFORMANCE:
Max Level Speed	at altitude: 585 mph (940 km/h) at 20,000 ft (6,095 m) [turbojet only] at altitude: 720 mph (1,160 km/h) at 40,000 ft (12,190 m) [mixed, conventional takeoff] at altitude: 1,250 mph (2,010 km/h) at 67,500 ft (20,575 m) [rocket only, air-launched] at sea level: unknown
Initial Climb Rate	unknown
Service Ceiling	unknown
Range	unknown
g-Limits	unknown
KNOWN VARIANTS:
D-558-2 #1	First example built and flown, initially powered by only a turbojet until rocket motors became available, used mainly by the US Navy
D-558-2 #2	Second example, used by NACA primarily to study the characteristics of swept-wings, only aircraft of the series to have mixed turbojet and rocket propulsion but was later modified to a rocket only configuration and air-launched from a B-29 mothership, set several speed and altitude records, now on display at the National Air & Space Museum
D-558-2 #3	Final aircraft built and powered by rocket motor only, also modified for air-launch only, used by NACA to explore the effectiveness of wing slats and leading edge devices as well as aerodynamic effects on under-wing stores at high-speeds
D-558-3	Proposed hypersonic research aircraft derived from the D-558-2, intended to reach Mach 9 at 750,000 ft (228,600 m) but was abandoned in favor of the X-15
KNOWN OPERATORS:	United States (US Navy) United States (NACA)
3-VIEW SCHEMATIC:
SOURCES: Aviation Enthusiasts Corner D-558-2 site Chant, Christopher and Taylor, Michael J.H. The World's Greatest Aircraft. Edison, NJ: Chartwell Books, 2006, p. 282, Douglas D-558-1 Skystreak and D-558-2 Skyrocket. Donald, David, ed. The Complete Encyclopedia of World Aircraft. NY: Barnes & Noble, 1997, p. 356, Douglas D-558-2 Skyrocket. NASA Dryden Research Center D-558-2 site National Air & Space Museum D-558 site Winchester, Jim. Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. San Diego, CA: Thunder Bay Press, 2005, p. 86-87, Douglas D-558 Skystreak/Skyrocket.