GRAHAM WARWICK / WASHINGTON DC
Development aimed at providing engine for S-92 presidential transport and to power upgraded AH-64s and UH-60s
General Electric has begun development of the uprated, 2,300kW (3,070shp) CT7-8C turboshaft. Development has been launched to support Sikorsky's offer of the S-92 to meet the VXX US presidential transport requirement, but the uprated engine will be available to power upgraded Boeing AH-64 and Sikorsky UH-60 helicopters.
The CT7-8C will provide 18-25% more power than the -8 engine now powering the twin-turbine S-92. The compressor and dual-channel full-authority engine control will be unchanged. The high-pressure turbine will use the same aerodynamics, with improved materials. The major change will be a new three-stage power turbine.
The first run of the new engine is planned for the end of this year, and GE will supply flight-test engines to Sikorsky in mid-2006. US Federal Aviation Administration certification is scheduled for mid-2007. If Sikorsky wins the VXX competition, deliveries would start in late 2007/early 2008. The additional power is required because the presidential transport mission equipment will add 1,800kg (4,000lb) to the S-92's empty weight, says Sikorsky.
GE says the uprated CT7-8C also provides a backup in case the US Army does not proceed with the Improved Turbine Engine Programme (ITEP) - formerly the Common Engine Programme - to develop a new 2,300kW-class engine. The uprated engine would meet the power requirement, but would not meet the ITEP goals for a 25% reduction in specific fuel consumption, and 60% increase in power-to-weight ratio.
Under the ITEP schedule, a technology demonstration programme would run from 2004 to 2008, so the engine would not be available before 2012.
Source: Flight International
