Douglas D-558-2 Skyrocket (Phase 2) - United States, 1948
Detailing the development and operational history of the Douglas D-558-2 Skyrocket (Phase 2) Experimental High-Speed Research Platform.
Entry last updated on 5/2/2016; Authored by Staff Writer; Content ©www.MilitaryFactory.com
The high-speed Douglas Skyrocket was built in three examples encompassing some 313 total test flights.
Prior to the end of World War 2 (1939-1945), the US Navy teamed with National Advisory Committee for Aeronautics ("NACA" - forerunner to NASA) and Douglas Aircraft to develop the Douglas D-558-1 series of research aeroplanes numbering three examples and known under the nickname of "Skystreak". The project originated as an ambitious program designed to collect data on transonic and supersonic flight. The program included three primary phases (Phase 1, Phase 2 and Phase 3) - Phase 1 became the D-558-1 proper while Phase 2 evolved to become the D-558-2 "Skyrocket" family of experimental vehicles. Phase 3 was a proposed armed and swept-winged, military-minded interceptor built upon the strengths of the Phase 1 and Phase 2 products.
Unlike the preceding D-558-1 model series - which was wholly powered by a turbojet engine and used straight wing units - the D-558-2 was given a hybrid rocket/jet propulsion system and swept-back wing assemblies. The type was therefore a more advanced offering when compared to the original Skystreak and bestowed the nickname of "Skyrocket" following the aptly-named "Skystreak". As with the Skystreak program, the Skyrocket program also begat three test vehicles in all - the first test vehicle going airborne on February 4th, 1948.
Externally, the Skyrocket followed some of the design lines of the original Skystreak. It utilized a deeper, more bulbous, tubular fuselage and featured a covered nosecone (as opposed to a nose intake). Wings were mid-mounted appendages (as opposed to low-mounted) and swept rearwards (at 35-degrees) for high-speed flight (as opposed to emanating straight out from the fuselage sides). The tail fin was sharper than on the Skystreak and given mid-mounted horizontal planes. There were no visible air intakes, only an exhaust port fitted under the tail unit. The undercarriage was retractable and consisted of two main legs and a nose leg, all wheeled and allowing the Skyrocket to take-off and land as a conventional aircraft. The cockpit was well-forward in the design though with poor vision due to the shallow windows and raised fuselage spine. Construction included magnesium at the fuselage and aluminum across the wings and tail unit.
The D-558-2 was powered by 1 x Westinghouse J34-WE-40 series turbojet engine developing 3,000lbs of thrust and supported by 4 x Reaction Motors (RMI) LR8-RM-6 rockets of 1,500lbs thrust from each unit. Take-off and climb would utilize the Westinghouse to which power would then be switched to the rockets for sustained high-speed level flight during testing. A Skyrocket test vehicle reached Mach 2 on November 20th, 1953 though in a dive - becoming the first aircraft in aviation history to achieve twice the speed of sound.
The D-558-2 program eventually produced three total vehicles for experimentation: The first airframe (D-558-2 #1) flew for 123 test flights during its tenure and this was followed by the second airframe (#2) with its 103 recorded flights. Airframe #3 managed a meaningful 87 total flights. The first airframe was given to the Planes of Fame Museum in Chino, California as a display piece while airframe #2 is currently on display (suspended on the second floor) at the Smithsonian National Air and Space Museum in Washington, D.C. Airframe #3 is perched atop a display pylon at Antelope Valley College of Lancaster, California.
The Skyrocket family of research aircraft served the United States well until December of 1956, providing valuable data during their years of active data-collecting service - particularly covering yaw and pitch actions in flight. Over its tests, the vehicle recorded a maximum speed of 720 miles per hour with a service ceiling of 16,500 feet. Its rate-of-climb was an impressive 22,400 feet per minute. The jet engine allowed for relatively short take-off runs and pilot control from Mach 1 to Mach 2 was deemed manageable despite some stiffness. The Skyrocket was also air-launched from under the wing of a B-29 research platform at an altitude of 35,000 feet and from this lofty start it could reach speeds of 1,250 miles per hour.