The battles between General Electric and Pratt & Whitney continue to dominate the US military engines market.

As new US military engine programmes become scarcer, each competition raises the spectre that one or more of the losers could be forced to leave the business. The stakes are highest at the most demanding end of the market, fighter engines, but across the power spectrum the consequences of losing a contest are mounting.

GE and its F136 Fighter Engine Team partner Rolls-Royce are once again battling to save funding for the beleaguered programme to provide an alternative engine for the Lockheed Martin F-35 Joint Strike Fighter.

The programme was cut from the most recent US defence budget request, but work continues, with the F136 successfully passing a preliminary design review under the system development and demonstration (SDD) phase on its way towards a planned critical design review at the end of this year.

The SDD phase was launched in August 2005 with a $2.4 billion contract, and is on track for the beginning of the first full engine runs in 2008. Tests to be carried out this year are focused on the F136's fan and low-pressure turbine, software and control systems, and afterburner.

If the programme survives, the first production F136 engines are scheduled to be delivered in 2012 to coincide with the fourth F-35 production lot. GE is developing the core compressor and high- and low-pressure turbines, controls and accessories, and the afterburner. R-R is supplying the fan and combustor.

Continuation of the F136 is key to GE remaining in the high-performance military engine business, although its F414 fighter turbofan orderbook has been bolstered by a $428 million deal to power 24 Australian Boeing F/A-18Es, while delivery of F110s for Singapore's Boeing F-15SGs are scheduled to begin in mid- 2008.

The US Navy has taken delivery of more than 700 F414s and production continues for both the F/A-18 E/F Super Hornet and electronic-attack EA-18G Growler, which first flew in August 2006. GE continues to hunt for new F414 sales on growth versions of the F404-powered Saab Gripen, Indian Tejas light combat aircraft (LCA) and Korea Aerospace Industries A/T-50 advanced trainer/light fighter.

Hindustan Aeronautics has ordered an additional 24 F404-IN20 engines to power the first operational squadron of Tejas fighters bound for the Indian air force. The $100 million order followed an initial 2004 purchase of 17 F404s, made to power a limited series of production aircraft and naval prototypes.

In 2006 the engine was installed in the LCA, leading towards flight testing, which is scheduled for the middle of this year. Based on the F404-402, the F404-IN20 is the highest-thrust version of the engine and includes a higher-flow fan, full-authority digital control and single-crystal turbine blades.

Work continues, meanwhile, on the upgrade of more than 200 F110s on US Air Force Lockheed F-16C/Ds as part of a service life extension programme. Funded under the USAF's F110 component improvement programme, the upgrade includes the core of the CFM56-7, three-dimensional aerodynamics, and a redesigned flowpath with changes to the combustor and high-pressure turbine, and is incorporated in all new F110s delivered from 2007.

Pratt & Whitney's F100 continues to challenge the F110 in ongoing F-15 and F-16 competitions, but having built around 7,000 of those engines, the company's focus is increasingly on its new fighter powerplants: the F119 in production for the Lockheed/Boeing F-22 and the F135 in development for the F-35.

F135 build-up

The build-up of F135s to support the F-35 development-test fleet continues with three conventional take-off and landing (CTOL) engines delivered to date. A fourth engine, the first for the F-35B short take-off and vertical landing (STOVL) variant, is due to be delivered in the fourth quarter of this year (see P30).

Under the F-35's revised development schedule, the first flight of the F-35B is due in May 2008. Overall, P&W is contracted to deliver 21 flight-test engines by the end of 2009, of which eight will be for CTOL F-35A tests, seven for the STOVL version and six for the F-35C carrier variant.

The F119, meanwhile, has become the mainstay of P&W's fighter engine production, and exceeded 40,000 flight hours last month. P&W is implementing a moving line for the F119 to improve productivity and pave the way for F135 production at its engine centre in Middletown, Connecticut.

Around 250 F119s have been delivered, with 60 more engines to be produced this year. P&W is looking to secure a multi-year procurement contract. If agreed in the third quarter of this year, the deal would cover the remainder of the currently planned F119s to be procured over the 2008-2010 period.

Production of the F100 is continuing, and the first F100-229 engine assembled at the P&W WSK PZL-Rzeszów facility was delivered in September 2006 under a deal to power Poland's F-16s. An unreheated version of the engine, the F100-220U, has been selected to power Northrop Grumman's X-47B contender for the US Navy's unmanned combat air system (N-UCAS) demonstrator.

For the future, P&W is studying possible military spin-offs from a common-core approach it hopes will provide the basis for a raft of new commercial, business aircraft and combat engines. Studies involve technology from derivatives of the F100 and F119 cores, as well as current commercial engines such as the PW6000.

Core size will depend on the emerging thrust requirements of single-aisle airliner projects as well as military programmes such as N-UCAS. The same core, equipped with an afterburner, would also be aimed at future combat aircraft and growth versions of types such as the KAI A-50 and Saab Gripen.

On the military turboshaft side of the business, GE consolidated its lead in January when Sikorsky selected a new engine, the GE38-1B, to power the US Marine Corps' CH-53K heavylift helicopter. Competing engines included the R-R AE1107, which powers the USMC's Bell Boeing V-22 tiltrotor, and Pratt & Whitney Canada PW150.

Borrowed features

Based on the architecture of the T700, and borrowing features from the GE27 demonstrator and CFE738 business-jet engine, the GE38-1B will produce more than 7,500shp (5,600kW) at sea level. Initial operating capability of the CH-53K is scheduled for 2015.

The 1,900shp-class T700 continues to be the leading US military turboshaft programme, powering the Boeing AH-64D, Lockheed VH-71A and Sikorsky H-60 family, and was further boosted South Korea's selection of the new -701K variant to power 245 indigenous helicopters to be produced under the Korean Helicopter Programme. The 701K is the first rear-drive variant of the T700.

The CT7-9C3 turboprop version of the T700 powers the EADS Casa CN-235-300 light transport, which is being delivered to the US Coast Guard as the HC-144A under a programme calling for procurement of 36 aircraft by 2017.

Honeywell's military turboshaft business is being sustained by production of the T55-714 to power upgraded Boeing CH-47F heavylift helicopters, new sales of the CTS800 developed through its Light Helicopter Turbine Engine (LHTEC) partnership with Rolls-Royce, and development of the HTS900-2.

The 970shp HTS900-2 is heading for certification in the third quarter of this year, to power the Bell ARH-70A armed reconnaissance helicopter (ARH). If the programme survives - cost overruns and schedule delays having led the US Army to order Bell to produce a "get well" plan or risk cancellation - the service plans to buy more than 500 of the single-engined scout helicopters.

T800 renaissance

The ARH is intended to replace the cancelled Boeing Sikorsky RAH-66 Comanche, the powerplant for which - the LHTEC T800 - is enjoying a renaissance as the 1,360shp CTS800-4, selected to power AgustaWestland's Future Lynx. Around 140 engines are required for 40 Lynx to be remanufactured for the British Army and 30 for the UK Royal Navy. First flight of the Future Lynx is scheduled for late 2009, with deliveries to start in 2011. The CTS800-4 is involved in six other campaigns including four military programmes, two of which could lead to awards this year.

Deliveries of T55-714 turboshafts for the CH-47 Chinook will slow to around 80 engines this year, but Honeywell is optimistic of securing orders for the 20%-uprated T55-715 based around a new compressor and marine-engine-derived core. The company expects to deliver the 1,000th T55-714 this year.

For the future Honeywell is working with the US Army's Aviation Advanced Technology Directorate (AATD) on its 700shp-class Small Heavy Fuel Engine (SHFE) demonstrator programme. This could result in a new turboshaft to be available from around 2010-11.

The SHFE effort began in 2003 and is a 46-month, $46 million partnership between Honeywell and AATD to develop an engine with 50% higher power-to-weight ratio, increased turbine temperatures and reduced noise and emissions over today's engines. Honeywell completed the first full engine test of its SHFE demonstrator in late February, with a second on track for July. A third, set for October, will map out performance improvements and durability.

Lockheed Martin 
The C-5M airlifter is re-engined with GE's CF6-80C2 large commercial turbofan

Source: Flight International