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Air Force Power Plant Laboratory worked on several foreign jet engines, including the British Sapphire (J65) and Olympus (J67), and the French Marbore (J69). The Wright J65 was US-built version of the Armstrong Siddeley Sapphire. In less than five years, the J65 went from powering the hotest American fighter in 1950, the F-84F, to being rejected as under-powered for the XF-104 in 1954.

The Sapphire was a hand tooled production of the British firm Armstrong Siddeley for which the CurtissWright Aeronautical Division at Wood Ridge NJ, had acquired a manufacturing license. However, the J65, as the Air Force version of the Sapphire was designated, was proved initially difficult to adapt to American specifications and manufacturing. Although the Wright production had been set to begin in September 1951, the J65 prototype engines consistently failed to meet USAF requirements. The new engine was also earmarked for the Republic F-84F. Due to the urgent need for improved fighter bombers since the outbreak of the Korean War, the Air Force in December 1950 selected the Buick Division of the General Motors Corporation as the second source for the Sapphire engine. In June 1952, when the Air Force finally accepted the first 2 YJ65-W-1 engines, neither had yet completed the required 150 hour qualification test.

The British Sapphire J65 engine was initially adapted by Curtiss-Wright for use in the F-84F Thunderstreak. The prototype flew in June 1950. The F-84F had a swept wing and tail instead of the straight wing-tail combination on the basic F-84. It also had a J65 turbojet engine with 7,220-pound thrust output, which gave the F model more speed than the F-86H, which was at that time the fastest American jet. Overall, the F-84F, which became operational in January 1954, was a far superior aircraft to its predecessor F-84 models.

As an intended replica of the English Electric Canberra B. Mk.2, the B-57A featured no outstanding innovations. Two Wright Aeronautical J65 turbojet engines were substituted for the Canberra's 2 Rolls Royce Avon turbojets. A Buick-built J65 was also used in the B-57 bomber. As with so many of the early jet aircraft, configuration of the B-57 was similar in concept to contemporary twin-engine propeller-driven aircraft but with jet engines replacing the reciprocating units. Power was provided by two non-afterburning J65-W-5 turbojet engines of 7200 pounds thrust each. Conventional rudders, ailerons, and elevators were used for control of the aircraft. Simple high-lift flaps were located in the wing trailing edge between the engine nacelles and the sides of the fuselage.

The FJ-3 carrier-based variant was powered by a single Wright J65-W-4 engine with 7,800 pounds thrust; it first flew in 1953. The FJ-4B Fighter used a single J-65-W-16A engine.

The A4D-1 "Skyhawk" attack aircraft was powered by a single J65-W-4 engine. The A4D-2 used the J65-W-16A. In February 1959, Douglas submitted a proposal for an A4D-5 as a follow-on to the A4D-2N. Improvements included installation of the lighter weight, 8,500 lb thrust Pratt & Whitney J52-P6A engine.

The F9F-9 was the planned designation for an F9F-8 powered by a Wright J65-W-6 engine. This aircraft was never delivered to the Navy.

The J65 steel-bladed engine had experienced a nunher of first-stage compressor-blade failures in service by 1955. The failures are the result of the blade ribrations and consistently occur in the second serration of the blade root., Stress analysis of the fir-tree-type roots of the first three stages of the compressor (the most critical stages from the vibration aspect) was undertaken to determine if it wa8 possible to eliminate failures by redesigntng the roots.

The XF-104 was fitted with a Wright J65 jet engine. A very long fuselage contained the cockpit and fuel cells, landing gear, and a single Wright YJ65-W-6 turbojet engine. This was supported by a pair of extremely short, anhedral supersonic wings with sharp leading edges that had to be padded to protect ground crews. The first flight was on 5 March 1954. This design had enormous promise, but subsequent flights soon revealed that the J65 could deliver a maximum speed of only Mach 1.79 (1,324 mph), approximately double that of the F-86 but still short of the Air Force's requirement of Mach 2.0 or better. The designers soon responded with a much-refined version of the troubled plane. They stretched the already-long fuselage by 5 feet, 6 inches in order to accommodate a new General Electric J79 axial-flow engine with 4,000 pounds greater thrust.

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One Billion Americans: The Case for Thinking Bigger - by Matthew Yglesias

Page last modified: 07-07-2011 02:37:14 ZULU