The Wright J65 was an axial-flow turbojet engine produced by Curtiss-Wright under license from Armstrong Siddeley. A development of the Sapphire, the J65 powered a number of US designs.
Curtiss-Wright purchased a license for the Sapphire in 1950, with plans to have the production lines running in 1951. However a series of delays due to design changes by Curtiss-Wright, such as substituting the Sapphire's machined midsection solid forged diffuser frame with a fabricated one of welded nodular iron,[1] led to its service introduction slipping two years. The fabricated assembly, a more practicable production job with about one fifth the cost, was subsequently adopted for the Sapphire.
Another change addressed the Sapphire's only major problem. The Sapphire was found to work well through the entire RPM range without the compressor stalling, which allowed it to dispense with inlet guide vanes or other solutions found on contemporary designs. However, in service it was found that while pressure was maintained even at low speeds and RPM, the first stages were stalling and this was causing significant vibration and fatigue issues. Wright solved this by adding inlet ramps that closed off the outer portions of the intake at low RPM. Armstrong Siddeley evaluated this for the UK Sapphires, but adopted a different solution instead.
By service introduction, the Pratt & Whitney J57 was on the market and took many of the J65's potential sales. Nevertheless, along with the Martin B-57 Canberra, its original application, the J65 went on to power versions of the North American FJ Fury, Douglas A-4 Skyhawk, Republic F-84F Thunderstreak, and the two Lockheed XF-104 Starfighter prototypes. Problems Grumman had with the engine in the F11F Tiger, particularly below-spec afterburning thrust, caused them to specify the General Electric J79 for the Grumman F11F-1F Super Tiger.[2]
As part of an expansion in defense contracts, Buick also built J65s.[3] Its version of the engine, the J65-B-3, was approved for use by the U.S. Air Force in 1953.[4] Components were produced by subcontractors including Oldsmobile, which built the compressor and turbine rotor assemblies; Harrison Radiator, which built the combustion chamber and tailcone; and Brown-Lipe-Chapin, which built the turbine stator blades and compressor stator assemblies. Final assembly was carried out in a 768000square feet portion of a purpose built plant in Willow Springs, Illinois.[5] [6]
A 6500shp10380shp turboprop version of the J65 (Sapphire) was developed by Curtiss-Wright as the Wright T49, and a commercial derivative, the Wright TP51A2 was also designed. The T49 first ran in December 1952 at 8000shp, followed by flight testing in a Boeing XB-47D test bed from 26 August 1955. By this time however, the market for the engine had vanished.[7]