The General Electric J79 was a turbojet engine, which was developed during the Cold War to power supersonic combat aircraft. It had a thrust-to-weight ratio of 3,500-lb weight and 15,000-lb+ thrust, which was unprecedented until then. It was the first US production engine, which was able to power aircraft at twice the speed of sound. It constituted the power plant of the Lockheed F-104 Starfighter and the McDonnell Douglas F-4 Phantom II.
Technical Characteristics
The General Electric J79 was an axial-flow type jet engine. Its major components were a 17-stage compressor section, an accessory drive section, a combustion section, a 3-stage turbine, a high-thrust afterburner, and a variable area exhaust nozzle. At first glance, it was a conventional turbojet engine with a high compression ratio.
Cool air that entered the engine went through the compressor section. Then the air was combined with fuel and ignited in burner cans. The high-energy combustion product went through the exhaust turbine, which in turn drove the compressor blades. The afterburner section was located in the aft portion of engine. The exhaust nozzle was continuously variable throughout the operating range of the engine.
The compressor of the J79 had seventeen stages and a single rotor. The stator first six stages and the inlet guide vanes were variable, adjusting automatically to reduce stall problems at low engine speeds. The rotor was composed of thin webbed discs and spacer rings bolted together. The compressor blades were made of steel and they attached to the discs by conventional dovetails. The discs of the first seven stages were manufactured with titanium.
The J79' separate fuel systems (main and afterburner) were flow-controlling units and hydro-mechanically operated. An emergency ram air turbine lowered from the right-hand side of fuselage provided hydraulic power in the event of engine seizure that left the primary system intact. This ram air turbine allowed safe flight, supplying emergency electrical power.
The J79 would be developed into the General Electric LM1500, which was a turboshaft derivative of aircraft engine for power generation.
Below, the J79-GE-7, which produced 15,800 pounds of thrust with afterburner.
The General Electric J79-GE-11A/B, which powered the F-104G variant of the Starfighter.
