General Electric YJ93

The YJ93 started life as the General Electric J79-X275, an enlarged version of the General Electric J79 turbojet with "275" meaning Mach 2.75, the engine's target operating speed. This design evolved into the X279 when Mach 3 cruise became a requirement, and ultimately became the YJ93. The engine used a special high-temperature JP-6 fuel. The six YJ93 engines in the XB-70 Valkyrie were capable of producing a thrust to weight ratio of 5:1 allowing for a speed of (approximately Mach 3) at an altitude of . The first engine went on test in September 1958 and featured advanced technology achievements such as electrolytically drilling longitudinal air cooling holes in the turbine blades. ==Variants==

Thrust given in foot-pounds (lbf) and kilonewtons (kN). ;J93-GE-1: with afterburner. ;J93-GE-3: Production variant produced in small numbers for the North American XB-70 Valkyrie program. ;J93-GE-3R: Variant with thrust reverser, with afterburner. ;J93-GE-3AR: Variant intended for the North American XF-108 Rapier. ==Applications==

• Convair NB-58A Hustler (testbed) • North American XB-70 Valkyrie • North American XF-108 Rapier (intended) ==Specifications (J93-GE-3)==