- General Electric T700
The General Electric T700 and CT7 are a family of
turboshaft andturboprop engines in the 1500-3000 shp class.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. 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.The T700 was initially bench-tested in 1973, passed military qualification in 1976, and went into production in 1978. 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 1,210 kW (1,622 SHP) intermediate power.The T700-GE-700 was followed by improved and uprated Army engine variants for the
UH-60 Black Hawk and theAH-64 Apache helicopters, as well as marinized naval engine variants for theSH-60 Seahawk derivative of the Black Hawk, the Kaman SH-2G Super Seasprite, and the Bell AH-1W Supercobra. T700s are also used on Italian and commercial variants of theAgustaWestland EH101 helicopter, and Italian variants of theNHI 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 theSikorsky S-92 derivative of the Black Hawk, all of which are twin-engine helicopters. There are also turboprop versions of the CT7.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 CzechLet L-610 G airliner, all twin-turboprop aircraft. The baseline CT7-5A provides 1,294 kW (1,735 SHP) 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 4,475 kW (6,000 SHP).
The YT706 is based on the CT7-8A engine.cite web |url=http://www.geae.com/aboutgeae/presscenter/military/military_20070813.html |title=GE YT706 Production Contract Awarded by US Army |accessdate=2007-08-16 |date=2007-08-13 |publisher=GE Aviation ] Compared with the T700 currently powering H-60 helicopters, the YT706 has a larger compressor, hot section improvements and a full authority digital engine control. The YT706 provides up to 30 percent more power than the current T700-701C and will increase the hot-and-high mission capability of the MH-60M Black Hawk procured by the U.S. Army for its Special Operations applications.
Applications
T700
* AH-1W/Z Supercobra
* SH-2G Super Seasprite
*UH-1Y Venom
*UH-60 Black Hawk
*SH-60 Seahawk
*AH-64 Apache
*HH-60 Jayhawk
*CH-148 Cyclone
*AgustaWestland EH101 /CH-149 Cormorant /VH-71 Kestrel
*NHI NH90
*Piasecki X-49 CT7 turboshaft
*
Bell 214ST
* Sikorsky S-70C
*Sikorsky S-92 CT7 turboprop
* CASA/IPTN CN-235
*Saab 340
*Sukhoi S-80 pecifications (T700)
pistonspecs
type=Turboshaft
length=47in (T700-GE-700/701 series) to 48.2in (T700/T6A)
diameter=25in / 26in (T700/T6E)
weight=437lb (T700-GE-700) to 537lb (T700/T6E)
compressor=6 stage-5 stage axial, 1 stage centrifugal.
combustion=Annular
turbine=
fueltype=
oilsystem=
power=1,622 shp (T700-GE-700) to 2,380 shp (T700/T6E)
thrust=
compression=17x
aircon=
turbinetemp=
fuelcon=
specfuelcon=0.433 (T700/T6E) to 0.465 (T700-GE-701A)
power/weight=3.71 shp/lb (T700-GE-700) to 4.48 shp/lb (T700/T6E)
thrust/weight=References
External links
* [http://geae.com/engines/corporate/cfe738.html General Electric CFE738 page] at [http://geae.com GE Aviation corporate website]
* [http://www.geae.com/engines/military/comparison_turboshaft.html GE Turbine Comparison Chart]
* [http://www.faqs.org/docs/air/v2003m10.html Vectors by Greg Goebel]
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