Andrzej Jeziorski and Guy Norris/FARNBOROUGH
International Aero Engines (IAE) may be celebrating its biggest ever V2500 order, the $2.5 billion deal to power up to 188 Airbus A320 family airliners for British Airways, but the partner companies seem intent on carving up the consortium rather than enjoying its belated success.
The future of the V2500 and the IAE consortium - comprising Roll-Royce, Pratt & Whitney, MTU and Japan Aero Engines - has been thrown into doubt following P&W's unilateral decision to go ahead with its own rival engine. This has opened up the prospect of the formation of a new partnership, including Rolls-Royce, BMW Rolls-Royce and others.
BMW R-R is planning to apply technology developed in Germany's Engine 3E research programme to a new turbofan family offering up to 35,000lb thrust (155kN), which could be launched in 2003. According to advanced projects and research studies department manager Helmut Richter, the company is hoping that its Engine 3E work will lead to the development of a high pressure-ratio engine core which would form the basis of the new family of engines, from a basic thrust of 25,000lb up to 30,000lb-plus - and possibly as high as 35,000lb. Senior BMW R-R officials say that this could form the basis of a successor to IAE's 22,000-35,000lb thrust V2500 family, one of which could realistically be operational by 2006.
CORE AIM
Richter says that the aim is to develop a new core with a nine or 10-stage compressor and an overall pressure ratio of 20-25:1. The current 10-stage BMW R700 core has a pressure ratio of 17. BMWR-R is restricted for now by agreements with UK shareholder R-R not to develop anything beyond 23,000lb thrust - the upper limit of the BMW R700 family's power range. It is understood that this may change, however, as a result of current discussions with R-R.
Engine 3E is a German Government-sponsored programme to develop technology for future quiet, clean and efficient powerplants. BMWR-R is partnered with Daimler-Benz Aerospace's MTU engine unit for development work under this programme.
BMW R-R is responsible for developing the "hot section" of the engine - the low nitrous oxide emission, two-stage combustor and the high pressure turbine - with MTU taking responsibility for the rest. Richter says that, until now, there has been no exchange of technology with MTU, and admits that MTU's long-standing strategic partnership with P&W calls into question the prospects for any future transfer of MTU technology into a V2500 successor.
The Anglo-German company is therefore working together with R-R on a "fallback position" to develop the remaining technology necessary for the new engine within the bounds of the European Fifth Framework research and technology programme, funded by the European Union.
BMW R-R and MTU are about to embark on a joint definition study for a full Engine 3E demonstrator engine, incorporating all the new technology the two partners have developed for the programme. The engine would be boosterless, with a high pressure-ratio core, staged combustor and a two-stage, high temperature turbine, and could be running in 2002.
Tests are already under way at the University of Stuttgart's high-altitude facility of a BMW R700 core which is used as a "test rig" for individual Engine 3E components. Staged combustor tests are due to be carried out on this engine in November, and tests next year will also include blade-integrated disks (blisks) in stages one and six of the compressor, and a new high pressure turbine air system to evaluate the growth potential of the existing turbine.
Pratt &Whitney started the current unravelling of the IAE partnership and the first part of its ambitious master plan slotted into place at the Farnborough show when Airbus Industrie announced that the A318, formerly the A319-M5, would be powered by the US manufacturer's new PW6000 engine.
The PW6000 forms the development basis for the PW8000, the geared-fan engine which P&W plans to use as its main weapon against CFM International's market-dominating CFM56 - and as a new generation successor to the V2500. In the long term, the PW8000 will also form the development platform for a proposed new generation of higher thrust engines that P&W says will replace its own PW2000 and PW4000 powerplants.
No-one outside Airbus and P&W knows what deal was cut to ensure the PW6000's place on the proposed 100-seater, but it is likely that the engine maker is carrying all the risk. The new P&W powerplant was chosen over the CFM56, which was also shortlisted from a selection which included the BMWR-R BMW R715 and the V2500. In some ways CFMI made life harder for itself by insisting on exclusivity - P&W took a similar stance over powering the A340-500/600 and the result was a victory for Rolls-Royce with the Trent 500.
Airbus has offered little comment on why the PW6000 was chosen. The price was right, but so too were the cost and performance benefits promised by P&W. "It will have 30% better maintenance costs and it has 40% fewer rotating parts than either the BMW R or CFM56," says P&W senior vice- president, programmes, Bob Leduc. "It has around 2,000 rotating parts, so when you compare it apples to apples there are far fewer parts to maintain and that's the key to keeping costs down in a market like this. We know the 100-seater market better than anyone else because we invented it."
Derived in part from core work performed under the US Government's Integrated High Performance Turbine Engine Technology (IHPTET) programme, the PW6000 has a four-stage low pressure compressor, five-stage high pressure compressor and a single-stage high pressure turbine. The powerplant also incorporates a single-stage low pressure turbine and a 1.42m-diameter fan. The fan is sized for thrust growth, and would have to be scaled down for use on smaller aircraft, such as the proposed ATR AirJet or Embraer RJ-170.
The first PW6000 is due to run in July 1999 and partnership deals are being finalised with several companies, including P&W's old allies MTU and Volvo of Sweden. Engine certification is scheduled for March 2001, with aircraft certification expected around August 2002 and entry into service the following September.
TECHNOLOGY DEVELOPMENT
Earlier this year CFMI outlined a broad-based technology development initiative aimed at keeping its CFM56 family competitive, as well as providing the basis for an all-new engine in the 20,000-35,000lb thrust class early next century. The programme is directed more against the threat posed by the PW8000, the BMW R700 family and potential successors to the V2500 than the PW6000, and was recently re-named Project TECH56 as the competition sharpened its focus and revealed its own initiatives.
The main targets of the programme include: a 15-20% lower cost of ownership; cumulative noise levels 20dB below Stage 3; up to 7% improvement in fuel consumption compared to the CFM56-5B/P; emissions as much as 50% lower than current regulation limits; and 15-20% lower maintenance costs. Getting there involves several major development initiatives, one of the main ones being a new swept blade, wide chord fan. Tests of the swept blade will begin in 1999, says CFMI.
Another area of study is the a new high stage-loading high pressure compressor (HPC) incorporating advanced three-dimensional computational fluid dynamics aerodynamics. Higher loading means fewer blades and rotors, which in turn translates into lower maintenance costs. The design of a rig to test an HPC with six stages compared to the current nine begins this year, with tests due in 2000. The pressure ratio target for the new HPC is 15:1. Another major departure from current engines is a planned close-coupled, counter-rotating, four-stage low pressure turbine, which will require studies of counter-rotating differential bearings. This will build on development work already undertaken for the YF120 fighter engine and new advances scheduled for the IHPTET effort.
This year also sees initial testing of a simpler, low emissions combustor. The new TAPS (twin annular, pre-swirl) combustor design is aimed at achieving the nitrous oxide emissions obtained with the new dual annular combustor, but with significantly lower carbon monoxide and unburned hydrocarbon emissions.
All the technologies under study will be validated by the end of 2000, says CFMI, which has outlined its intention of fielding a new generation engine by 2004-5.
Source: Flight International
