Two years ago, the world's three big engine makers - General Electric, Pratt & Whitney and Rolls-Royce - were at the Paris air show, fighting over the future direction of thrust growth for one major programme, the Boeing 777. Other airframes, and their potential derivatives, were very much in the background - which was just as well for the engine makers, which were spending huge amounts of money on their 777 efforts.

Some things have changed, others have not. The 777 growth plan is still very much on the agenda, with 445kN (100,000lb)-thrust and upwards the target for the ultra-long-range 777-200X and extended-range 777-300 stretched derivative. Engine makers are over the worst of their investment curve on the big engines, but face the challenges of new derivatives, as well as trying to make a return on current sales. The big change over the past year particularly, and one that will be borne out at Paris, has been the acceleration of other airframe efforts and their related thrust demands.

Boeing's near-term focus remains fixed on the 777, and it hopes to give the go-ahead to one, and possibly both, these new derivative programmes at the show. Everything depends on the engine makers. Without the ability to reach these high thrust-levels at reasonable cost and safety margins, the 777-200X/300X programmes would not be happening. Both are heavily reliant on each other. The power demand is driven by the -200X, which will have a maximum take-off weight of around 327,000kg, making it the largest twinjet ever developed. The weight and performance of the longer, but slightly shorter-range -300X, will "fall out" of the engines developed for the -200X, says Boeing.

General Electric has put down its marker on the next thrust jump by becoming the first to sign an agreement with Boeing, offering the GE90-100B and 102B derivatives of the current GE90. Rolls-Royce (2/B19 chalet 244/B, 246/B) followed suit by signing a similar memorandum of understanding on the development of engines dubbed the Trent 8100 (for the -200X) and the 8102 (for the -300X). R-R is again in catch-up mode, having reversed the trend for the first time, ironically with the standard 777-300, which it will be first to power, for the first time in any Boeing widebody programme. It has stepped up its development effort and now plans to have an engine ready for service by January 2001. This is still up to four months behind GE and Pratt & Whitney (2/E15, J8, K8, 61/A) which, by the eve of the Paris show, was expected to have sanctioned uprating the PW4098 to 445kN for the new twins.

P&W held off committing to this further growth step, but began considering the move when it came under increased pressure from many of its Asian-based 777 customers such as Korean Air and Asiana. Happily for the US engine maker, results from its PW4098 development tests at the Arnold Engineering Development Center were better than expected, giving it the opportunity to grow quickly, easily and, above all, affordably, to the higher-thrust requirement. Boeing acknowledges that P&W has the definite advantage in the race, but only for those loyal customers which do not require the range for such routes as Singapore-Los Angeles, or Dallas/Fort Worth-Tokyo.

Although the demise of the rewinged 747-500X and -600X effort in January came as a shock to some, it was viewed with relief by most within the aerospace business. This was not the case in the engine community, which had successfully re-aligned itself to cope with the prospect of another expensive development effort. The GE P&W Engine Alliance (2/J15), established to develop the GP7000 family for the new 747s has been redirected towards the Airbus A3XX and its less-demanding timescale. R-R, which had scrambled to react by offering its Trent 900 derivative for the 747-X, and which had enjoyed a definite advantage in the competition for a long time, has re-aligned its efforts towards Airbus.

No sooner had the dust settled, however, than Boeing revived its earlier 747-400 growth studies, sending the engine makers in yet a new direction. The -400IGW (increased gross-weight) and a potential 80-passenger stretch of the strengthened -400 airframe demands a new engine with at least 289kN thrust. Although this is below the GP7000 limits originally sketched out for the 747-X efforts, GE and P&W are known to be studying the -400IGW plan with interest. The death of the rewinged 747 posed a serious legal challenge to the existence of the joint venture, and one which both parties felt increasingly uncomfortable with, as their sole remaining sales prospect was Airbus.

Cracks soon showed in the yet-to-set concrete of the alliance when P&W began separate discussions with Airbus earlier this year over powering the A3XX with a derivative of the PW4000 family. This followed another agreement that had already been signed between R-R and Airbus over the use of the Trent 900 on the A3XX. The ambitious Airbus programme had already been accelerated before the death of the 747-X to compete with Boeing's original 2001 entry-into-service target, and therefore did little to relieve the pressure on the engine makers. With the Alliance seemingly on the brink of collapse, or at least falling into a coma, the potential dual applications of the revived 747-400IGW/stretch and A3XX seemed to provide a lifeline.

Paris will prove whether this is simply a false hope. GE, for example, has begun work on a "bolt-less turbine" version of the CF6-80C2, dubbed the BSF, which has effectively been launched by a Delta Air Lines order for the stretched Boeing 767-400. This engine would also provide enough thrust for the proposed 747 derivatives with only minor changes, and GE will be sorely tempted to forgo any Boeing applications of the GP7000 as a result.

P&W's unilateral stance on the A3XX, and its determination to challenge GE and R-R on future 767 derivatives, is sure to drive a further wedge into the alliance. Adding to the pressure is Boeing's plan to offer yet another 767 derivative, the -300X, which would use the wings and engines of the -400 stretch on the -300 extended-range fuselage.

R-R, meanwhile, is determined not to be left out in the cold on the 767. At a time when it was concentrating hard on developing the RB.211-524G/H for the 747-400, it had been forced, almost, by British Airways into developing the same engine series for the UK airline's 767-300 fleet. The result was a marginal market with equally marginal returns and a litany of problems which eventually forced the development in 1996 of the RB.211-524/Trent 700 hybrid. This is in final development, and may be flight-tested as early as September if R-R can get hold of a suitable 747 airframe. The improved engine will be offered on the 747-400 and existing 767 family, but is not suitable for the growth models.

R-R's strategy to get its teeth into the new 767 and 747 families is founded squarely on its Trent 700/800 series, which is now in service on both A330 and 777, respectively. Although suffering teething problems in both versions, R-R is generally pleased with both technical and commercial successes of the family, which is set to provide further dividends by generating growth for the new airframes under study.

The engine under study for the 767 and 747-400IGW is the Trent 600, which combines the scaled-down Trent 800 core with the same 2.5m-diameter fan of the Trent 700. The actual development route would probably follow that of the Trent 500, which is the R-R solution for the Airbus A340-500 and growth A340-600 models. The Trent 600, offering a bypass ratio of 9:1, is therefore considered as a "re-bladed" outgrowth of the Trent 500, rather than either the Trent 700 or 800.

The hottest European-based topic at Paris will be the power battle over the two Airbus A340 growth models. Mystery surrounds GE's position following the demise of its exclusive agreement with Airbus. The R-R position is firmly linked to the 245-290kN Trent 500 engine and, like P&W, the company hopes to sign a "sole-source" agreement with Airbus.

P&W was in earnest "business discussions" with Airbus over the same goal during the run-up to the show. After years of discussing the possible use of the ultra-high-bypass Advanced Ducted Propulsor on future A340 models, the engine maker is banking on a more conventional powerplant for its winning hand. The discussions revolve around an engine called the PW4557, which combines the 2.37m-diameter titanium fan and low-pressure spool of the 258kN PW4158 engine for the A300-600, with the high-pressure spool of the 777's PW4098.

To meet the wide range of take-off weight requirements now projected by Airbus, the PW4557 is aimed at covering a thrust range varying from 253kN at the lower weights to almost 276kN, almost double the thrust of the current aircraft's CFM56 engines.

CFM International (CFMI) (2/K9 chalet 226B/B) is not overly worried about encroachment on the A340. The joint GE-Snecma company continues to ramp up CFM56 production on the back of the sales success of the next-generation Boeing 737 family and steady sales of the A320 series and the A340. To the surprise of Boeing and CFMI, the current generation of 737 remains a constant seller, and plans to reduce production of airframe and engines for the -300, -400 and -500 models have been revised. In 1996, CFMI won orders for 1,280 engines, giving it an estimated 61% of the global market in the 100-150kN thrust range. The company is therefore in the throes of gearing up for a dramatic increase in production from 443 engines in 1996 to 750 in 1997 and 920 in 1998. The rate may increase further still if the present sales rate of the 737 is maintained. Boeing's plans to offer another stretch, the 737-900X and a commercial variant of the hybrid business jet, dubbed the -700X in airliner guise, may add to the pressure.

CFM's direct competitor, International Aero Engines (IAE) (2F/15 310/D), does not enjoy the benefit of exclusivity on anything other than the McDonnell Douglas (MDC) MD-90, which has produced only moderate sales to date and, with the prospect of the Boeing/MDC merger looming, faces an uncertain future. IAE's success with Airbus, however, has been pronounced and, based largely on the V2500A1 and A5 series, sales have reached $3 billion with almost 300 V2500-powered aircraft in service. IAE has also launched a major effort to cut maintenance costs by 25% by the end of 1998 and is chasing the burgeoning market in Asia with vigour for new A320/MD-90 sales.


Source: Flight International