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[1964.105.001] Aircraft - 'D-558-1 Aircraft, Bureau Number 37970' |
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D-558-1 Aircraft, Bureau Number 37970
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| Accession Number |
1964.105.001 |
| Accession Date |
23/12/1964 |
| Creator |
| Creator |
Creator Role |
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Manufacturer |
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| Date Created |
04/10/1947 |
| Object Desciption |
The Douglas Aircraft Co. developed and built D-588-1, Bureau Number (BuNo) 37970, under supervision of the Navy's former Bureau of Aeronautics (now the Naval Air Systems Command) in a joint program with the National Advisory Committee for Aeronautics (NACA). Primary investigative mission for BuNo 37970 and two sister D-588-1 airframes was high-speed aircraft performance. Douglas provided the Navy with the first design drawings for Skystreak on April 13, 1945. The first D-588-1 airframe completed, BuNo 37970, was delivered to test facilities at Muroc Dry Lake, CA, on April 10, 1947. Its first flight was attempted two years from initial design almost to the day, on April 15, 1947. The early flights experienced difficulties with a variety of aircraft components, largely in the undercarriage, and none having any significant design implications. These were ironed out by July 1947.
In design, a single GE TG-180 turbo-jet engine powered the Skystreak; when later produced by Allison it was designated the J-35-A-11, having 5,000 lbs. of thrust. The plane is constructed largely of magnesium alloy and its skin is sensitive to scratching and any pressure, rendering significant the manner and maintenance of its finish. Hatches, fittings, jacking and lift points were designed with that sensitivity in mind. Because applicability to then-contemporary military combat aircraft was a development priority the Skystreak is otherwise of generally conventional, straight-wing (4 degree dihedral) design, with a large air intake in the nose, and pilot seated ahead of the engine proper. Integral fuel tanks were located in the forward areas of the wings. Additional fuel could be carried in wing-tip tanks. As originally built BuNo 37970 was fitted with a clear "bubble" canopy; this was replaced in anticipation of high-speed tests with a hooded metal and glass canopy with a "V" shaped forward panel. In practice, however, that special change was probably not necessary.
Just over four months after 37970's inaugural flight, on August 20 1947, CDR T. F. Caldwell, USN, Navy Project Officer, set a world speed record of 640.7 mph over a 3 km measured course (average of four runs). Five days later that record was broken by Major Marion E. Carl, USMC, setting a new world record of 651 mph. Record flight altitudes were below 1,200 feet The planned operational ceiling for the D-558-1 airframes was 45,700 feet and flights were of relatively short duration. Though originally intended to reach no more than eight-tenths of the speed of sound BuNo 37970 did reach Mach 1.0 (it's program sister, the Douglas Skyrocket, reached Mach 1.88, 1,240 mph), approaching a limit for an airframe of its configuration. The Mach 1.0 event occurred on September 29, 1948 when BuNo 37970 reached that speed in a dive of 35 degrees. At the time it was the highest speed ever reached by an airplane capable of taking off under its own power. Douglas concluded their investigations with this airframe in April 1949, having made more than 100 flights, delivering the plane to NACA on April 21st possibly to operate at Edwards Air Force Base. It is not known how many flights may have been made under NACA but D-588-1 BuNo 37970 was grounded, serving as a source of spare parts for D-588-1 BuNo 37972 (BuNo 37971 crashed on a NACA test flight). |
| Place of Origin |
El Segundo, California |
| Notes |
The Navy Transonic Research Project was originated in 1944 as a joint venture of the U.S. Navy, the National Advisory Committee for Aeronautics (NACA), and the Douglas Aircraft Company. The need for aircraft operating in the transonic region was visualized while WW II was still in progress. The German Luftwaffe had aircraft approaching such speeds before the war's end. The purpose of the program was to explore and gain full-scale aerodynamic data for development of military aircraft operating at Mach 1.0 and beyond. The program yielded six D-588 airframes, of which three (D-588-1) were designated the Douglas Skystreak and three (D-588-2) were designated the Douglas Skyrocket.
All three D-588-1 aircraft, bearing BuNos 37970, 37971, and 37972, were powered by single GE TG-180 (Allison J35-A-11) turbo-jet engines. Douglas retained BuNo 37970 for performance and flight profile exploration before turning it over the NACA. The other two Skystreaks were delivered to NACA for their investigations. BuNo 37971 was delivered to NACA in October 1947 but crashed in tests in May 1948. Bruno 37972 was delivered to NACA in January 1949 and is today on display at the U.S. Marine Corps Museum, Quantico, VA.
The D-588-2 aircraft were intended to explore still higher performance flight profiles. Of swept-wing design, with negative dihedral, they were configured variously to fly on jet power alone, rocket power alone, or a combination of the two. BuNos 37973 and 37974 were originally configured with a jet engine only. A rocket engine was subsequently added to BuNo 37973, as was 37975, providing these aircraft with both sources of power. BuNo 37974 was later stripped of its jet engine and equipped with a rocket engine only. The jet engines involved were Westinghouse 24C (or J34-WE-40) products. The rocket engine was a Reaction Motors LR8-RM-2.. In exploring the limits of its performance envelope the D-588-2 program included air-launch from a Navy-flown modified B-29 (designated as a P2B-1S). The tests projected an airframe capable of super-sonic speeds at altitudes of 80,000 feet. The D-588-2 Skyrocket aircraft are last known to be disposed: 37973 at the Ontario Air Museum, CA; 37974 at the Smithsonian Air & Space Museum, Washington, DC; and 37975 is displayed at Antelope Valley College, Lancaster, Califronia.
Specifications for D-558-1
Manufacturer: Douglas Aircraft Company
Dimensions: Length: 35 ft. 8 ½ in.; Height (vert. stabilizer): 12 ft.1 3/4 in.; Wingspan: 25ft.
Weight: Bare: 9,750 lbs.; Gross Takeoff - 10,105 lbs. (10,897 w/tip tanks); Landing - 7,711 lbs.
Power Plant: General Electric TG-180/Allison J35-A-11) Turbo-jet engine
Performance: Max. 651 mph in level flight over measured course.
Maximum Range: N/A
Armament: None
Ordnance: N/A
Crew: Pilot |
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