General Electric J85 (Engine)

The General Electric J85 is a small single-shaft turbojet engine. Military versions produce up to 2,950 lbf (18 kN) of thrust dry, afterburning variants can reach up to 5,000 lbf (22 kN). The engine, depending upon additional equipment and specific model, weighs between 300 to 500 pounds (140 kg to 230 kg), giving it the highest thrust-to-weight ratio of any production turbojet in the world. It is one of GE's most successful and longest in service military jet engines, the civilian versions having logged over 16.5 million hours of operation. The United States Air Force plans to continue using the J85 in aircraft through 2040. Civilian models, known as the CJ610, are similar but supplied without an afterburner, while the CJ700 adds an uncommon rear-mounted fan for improved fuel economy.

General characteristics

• Type: Afterburning turbojet engine
• Length: 45.4 to 51.1 inches (depending on accessory equipment installed)
• Diameter: 17.7 inches
• Dry weight: 396 - 421 pounds (depending on accessory equipment installed)

Components

• Compressor: 8 stages (9 in J85-21)
• Combustors: annular
• Turbine: 2 stages

Performance

• Thrust: 2850 - 3100 lbf thrust (dry)
• Specific fuel consumption: 0.96 - 0.97
• Thrust-to-weight ration: 7.5(-21),6.6(-5),6.8(-13),7(-15)