General Electric TF39 Turbofan

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About the TF39 Turbofan:

The General Electric TF39 is a two-spool high-bypass turbofan engine. It was developed in the 1960s to power the U.S. Air Force C-5 Galaxy military transport aircraft.

General Electric was awarded a U.S. Department of Defense (DoD) contract to develop the TF39 in 1965 and the first engine went into test the same year. Between 1968 and 1971, a total of 463 TF39-GE-1 and TF39-GE-1A engines were produced and delivered to power the C-5A Galaxy (four engines per aircraft). In February 1983, Lockheed Martin ordered 200 TF39-1C turbofans (43,000 pounds of thrust) to power 50 C-5B Galaxy aircraft. The first TF39-1C engine was delivered in January 1985 and the 200th and final engine shipped in November 1988.

The TF39 was developed into the CF6 Family of commercial turbofan engines designed for installation on commercial wide-body aircraft. Since the introduction of the CF6, the TF39 has benefited directly from new CF6 design technology in the form of components, materials, processes, manufacturing techniques, and repair processes.

The Lockheed Martin C-5 Galaxy is the largest aircraft operated by the U.S. armed forces. Using the front and rear cargo openings, the Galaxy can be loaded and off-loaded at the same time. Both nose and rear doors open the full width and height of the cargo compartment. The aircraft routinely carries 73 troops and 36 standard 463L pallets. The C-5 fleet was delivered to the Air Force from 1969 to 1989. C-5A/B/C aircraft are currently being re-engined with new CF6-80C2 (F138-GE-100) turbofans. Re-engined C-5s carry the C-5M Super Galaxy designation. As of September 2015, only 25 legacy C-5s remain in the Air Force inventory compared to as many as 111 aircraft in January 2011.

The TF39 was the first high-bypass turbofan engine in the world. It was a great leap in aircraft engine design offering higher thrust levels and greatly improved fuel efficiency. The TF39 included pioneering technological accomplishments such as an 8-to-1 bypass ratio, a 25-to-1 averall pressure ratio at maximum power, a 2,500*F turbine temperature, which was made possible by advanced cooling techniques. Also it featured a General Electric thrust reverser. The TF39 fan, compressor, combustor, turbine, and exhaust system were almost perfectly matched, and each system was significantly more efficient than those of competing engines.

Sources Used: U.S. Department of Defense (DoD) and General Electric Co.

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Engine Type:

Two-Spool High-Bypass Turbofan Engine


C-5 Galaxy


Currently being phased out.


General Electric Co.

Price/Unit Cost:


General Electric TF39 Turbofan Engine

By Joakim Kasper Oestergaard Balle /// Contact Forecast International

External Resources:

GE Aviation's TF39 Page: Not Available

YouTube: General Electric TF39 on YouTube

Fact Sheet: General Electric TF39


Engine Specifications: General Electric TF39-GE-1C

Manufacturer: General Electric Co.
Thrust: 43,000 pounds
Overall Pressure Ratio at Maximum Power: 25
Thrust-to-Weight Ratio: 5.38
Bypass Ratio: 8
Compressor: Two spool, axial flow, 1.5-stage fan
LP-HP Compressor Stages: 5-16
HP-LP Turbine Stages: 2-6
Combustor Type: Annular
Length: 26 ft (7.92 m)
Diameter: 97 in (246 cm)
Dry Weight: 8,000 lbs (3,629 kg)
Platforms: C-5 Galaxy
Price/Unit Cost: Unknown
First Run: 1964
First Flight: June 30, 1968

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