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T700 / CT7
Type Turboshaft
National origin United States
Manufacturer GE Aviation
First run 1973
Major applications Bell AH-1W SuperCobra
Bell AH-1Z Viper
Bell UH-1Y Venom
Boeing AH-64 Apache
CASA/IPTN CN-235
KAI KUH-1 Surion
Saab 340
Sikorsky UH-60 Black Hawk
Sikorsky SH-60 Seahawk
Number built Over 20,000[1]
Developed into General Electric T901[citation needed]

The General Electric T700 and CT7 are a family of turboshaft and turboprop engines in the 1,500–3,000 shp (1,100–2,200 kW) class.

Design and development

In 1967, General Electric began work on a new turboshaft engine demonstrator designated the "GE12" in response to US Army interest in a next-generation utility helicopter.[2] The GE12 was designed and conceived by GE's Art Adamson and Art Adinolfi. In 1967, both GE and Pratt & Whitney were awarded contracts to work parallel with each other to design, fabricate, and test the technology.[2] The Army effort led, in the 1970s, to development of the Sikorsky S-70 Black Hawk, powered by twin GE "T700" turboshafts, the production descendant of the GE12.[2]

The T700 was initially bench-tested in 1973, passed military qualification in 1976, and went into production in 1978.[3] The initial "T700-GE-700" is an ungeared free-turbine turboshaft, with a five-stage axial / one-stage centrifugal mixed-flow compressor, featuring one-piece "blisk" axial stages, with the inlet guide vanes and first two stator stages variable; an annular combustion chamber with central fuel injection to improve combustion and reduce smoke; a two-stage compressor turbine; and a two-stage free power turbine with tip-shrouded blades. The engine is designed for high reliability, featuring an inlet particle separator designed to spin out dirt, sand, and dust. The T700-GE-700 is rated at 1,622 shp (1,210 kW) intermediate power.

The T700-GE-700 was followed by improved and uprated Army engine variants for the UH-60 Black Hawk and the AH-64 Apache helicopters, as well as marinized naval engine variants for the SH-60 Seahawk derivative of the Black Hawk, the SH-2G Seasprite, and the Bell AH-1W Supercobra. T700s are also used on Italian and commercial variants of the AgustaWestland EH101/AW101 helicopter, and Italian variants of the NHIndustries NH90 helicopter. These are all twin-engine machines, except for the three-engined EH101.

The commercial version of the T700 is the "CT7", with the engine used on the Bell 214ST (an enlarged version of the Huey), commercial Black Hawks, and the Sikorsky S-92 derivative of the Black Hawk, all of which are twin-engine helicopters.

The CT7 turboprop variants use the same core as the turboshaft variants, with a propeller gearbox fitted forward of the core. CT7 turboprops are used on variants of the Swedish Saab 340 airliner, the Indonesian-Spanish Airtech CN-235 cargolifter, and the Czech Let L-610G airliner, all twin-turboprop aircraft. The baseline CT7-5A provides 1,735 shp (1,294 kW) on takeoff.

In the late 1980s, GE also proposed a much larger turboprop, the T407/GLC38, with a five-stage axial/one-stage centrifugal mixed-flow compressor, an annular combustor with 15 burners; a two-stage compressor turbine, a three-stage power turbine, and max takeoff power of 6,000 shp (4,475 kW).

The YT706 engine is based on the CT7-8A engine. Compared with the H-60's primary T700 engine, the T706 has a larger compressor, hot section improvements, and full authority digital engine control.[4] The T706 is rated at 2,600 shp (1,939 kW) and increases the hot-and-high mission capability of the U.S. Army's MH-60M Black Hawk for Special Operations applications.[5]

Variants

US Marines perform maintenance on the T700-GE-401C from a Bell UH-1Y helicopter

T700: Military turboshaft engine.

CT7 turboshaft: Commercial version of T700.

CT7 turboprop: Turboprop version of CT7.

Applications

A U.S. Navy Sailor performing maintenance on a T700 engine from a MH-60R Sea Hawk.

T700/CT7 turboshaft

YT706 turboshaft

CT7 turboprop

General characteristics

Components

Performance

Specifications (T700)

See also

Related development

Related lists

References

  1. ^ Kover, Amy; Kellner, Tomas (December 16, 2019). "Stayin' Alive: Trusty GE Chopper Engine That Entered Service When The Bee Gees Ruled The Charts Wins New $1 Billion Lease On Life". GE Reports: Future of Flight. Retrieved May 15, 2021.
  2. ^ a b c Leyes, Richard A.; Fleming, William A. (1999). The History of North American Small Gas Turbine Aircraft Engines. AIAA. ISBN 9781563473326. Retrieved 5 October 2017.
  3. ^ "Unknown Title". Verti-flite, Volume 37. 1991. Retrieved 5 October 2017.
  4. ^ "GE YT706 Production Contract Awarded by US Army". GE Aviation. 2007-08-13. Archived from the original on 2007-10-23. Retrieved 2007-08-16.
  5. ^ "Sikorsky S-70A." (online subscription article) Jane's All the World's Aircraft, 25 May 2016.
  6. ^ "The General Electric T-700/T-701C". Archived from the original on 2014-05-02. Retrieved 2022-07-09.
  7. ^ "TEI TO POWER BLACKHAWKS |". www.tei.com.tr. Archived from the original on 2016-09-19. Retrieved 2016-09-17.
  8. ^ "T700-701K turboshaft engines datasheet" (PDF). GE Aerospace.
  9. ^ a b "The CT7 Engine - GE Aviation". www.geaviation.com.
  10. ^ John W.R. Taylor, ed. (1988). Jane's All the World's Aircraft 1988-89. London: Jane's Information Group. ISBN 0-7106-0867-5.
  11. ^ Govt Competitive Test UTTAS YUH-60A, USAAEFA Proj # 74-06-1
  12. ^ "GE YT706 Power Specifications". GE Aviation. Archived from the original on 2011-06-14. Retrieved 2011-06-02.
  13. ^ Peter deBock (September 18, 2019). GE turbines and small engines overview (PDF). ARPA-e INTEGRATE meeting. Global Research. General Electric.

The initial version of this article was based on a public domain article from Greg Goebel's Vectorsite.