Guy Norris/BERLIN
Within four months, the first BMW Rolls-Royce-powered Boeing 717-200 will enter service with launch customer AirTran Airways. It promises to be a major event, particularly for an engine company that did not run its first core powerplant until August 1993.
Since then, BMW Rolls-Royce has seen year-on-year growth. By early this year it had accumulated firm orders for more than 900 engines worth over DM3 billion ($1.5 billion). Production of BR710 and 715 engines is being ramped up rapidly to meet demand and will see annual deliveries virtually double from a combined tally of over 100 engines last year to almost 200 this year. Production next year is forecast to be around 260 engines, prompting the company to sanction a major expansion of capacity at its Dahlewitz site south of Berlin.
The production ramp-up will see assembly of up to 140 BR710s and 120 BR715s a year from 2000 onwards. The number of BR715s could rise, depending on the sales success of the 717 and Boeing's willingness to increase the production rate. "It's a big challenge," says BMW Rolls-Royce chairman Dr Klaus Nittinger. "Boeing intends to produce five aircraft a month, so we have to supply 10 engines a month. We can adapt up to 15 engines a month, and if needed, we have the ability to assemble engines in Derby [at Rolls-Royce in the UK], because they have the capability and have worked on the V2500, which is a similar engine in some respects," he adds.
The bulk of the order book is made up of the BR710, which powers Bombardier's Global Express business jet as well as the GVbuilt by its arch rival, Gulfstream. It was also selected in 1996 to power the British Aerospace Nimrod MRA4 maritime patrol aircraft and up to 88 engines are to be produced for this programme. The Global Express order book stands at more than 160 engines, while that for the GV is at 400 units, taking firm orders for the BR710 to more than 650 engines. The BR715 order book stands at just over 230, with the company hoping for new orders to materialise later this year.
Long-term prospects
In many ways, the long-term success and much of BMW Rolls-Royce's credibility is expected to rest on the BR715. Launched with McDonnell Douglas' MD-95 project in October 1995, the engine first ran in April 1997 and powered the prototype 717-200, as it was by then called, into the air in September last year. After overcoming initial problems with containment and turbine blade cracks, the engine has earned a reputation at Boeing as a trouble-free and fuel-miserly performer. "We are very pleased that not only the engine performance, but also the performance of the whole aircraft, is beyond expectations in terms of fuel burn," says Nittinger.
"Cruise specification range has improved by 5% against block value [which is nominal], and against guarantees. Of this, around 1.5% is due to the engine, which we estimated as a result of test cell results". Nittinger says the company was not surprised "because based on BR710 experience, we predicted its performance pretty closely". Now Nittinger is conscious of the all-important entry into service phase, when airlines will be watching how the engine stands up to the wear and tear of daily operations. "We have to get the product to market and make sure it is rugged and reliable. That's the next aim. If we demonstrate that, then we can have the basis for improvement."
Much of this could be concentrated on further versions of the 717 line, namely the proposed shorter 90-seat -100 and its stretched stablemate, the heavier gross weight -300. "We have a growing amount of interest in a family of 717s, particularly in Europe for the 90-seater," Nittinger says. "Even though the -100 would be economically more difficult that the -200, it would provide easier access to the market, which is below the league of the aircraft such as the 737 and [Airbus] A319 flying it today." BMW Rolls-Royce will certainly stick to simple BR715 derivatives, both derated and uprated, for any new 717 applications, but is awaiting Boeing's lead on the next move. "We want them to define the launch conditions, the number, the customers, the price and the time," says Nittinger.
Despite its open enthusiasm for possible new BR715 business at the top end of the regional business, BMW Rolls-Royce is under no illusions about the pressures on the 100-seater market. "It's a very tough market because most of the aircraft will be purchased by the established airlines and they have price expectations. The problem for Airbus is to get a real price for the A318 and Boeing for the 717, because sister airlines are willing to pay much more per seat for 50- or 70-seaters. You are in the middle, so therefore there is a tremendous price pressure on 100-seaters," says Nittinger.
Reflecting on the company's failure to secure a place on the A318, Nittinger adds: "The whole decision for us was driven by economics. We would have liked to have increased our market share, but not at any price. It was insane business, and the people pushing the [Pratt & Whitney] PW6000 were desperate."
Further off, Nittinger suggests that BMW Rolls-Royce could provide a standalone successor to the International Aero Engines (IAE) V2500. Rumours circulating at the 1998 Farnborough air show suggested that Rolls-Royce was keen to buy out Pratt & Whitney's stake in IAE, following the US engine maker's openly revealed intent to develop the geared fan PW8000 as a direct competitor to the GE/Snecma CFM56, and by default, the V2500. At the time, BMW Rolls-Royce was also mentioned as a possible vehicle for this development, although nothing was said definitively at the time.
"We have the potential to grow the 715 and we have the technology to further develop the high-pressure [HP] compressor. We can go to 22,000lb thrust [98kN] with no changes, and then to 25,000lb with some material changes," says Nittinger. He adds: "We have not applied any exotic materials or sophisticated cooling to our designs. All of that represents opportunities up our sleeves". One potential upgrade under study is the addition of an advanced first-stage HP cooling system, as well as new thermal barrier coatings. This could generate up to 1,000lb additional thrust, taking overall maximum power levels to 23,000lb.
Regional proposals
In the near term, BMW Rolls-Royce has proposed the BR715-50 to Embraer for the ERJ-170/190 regional jet family - a decision on which was due to be announced as Flight International went to press. Embracing the low-pressure system of the BR710 and the high-pressure elements of the BR715, the -50 is "not just a minor tweak, and would be considered the first major new derivative", says head of concepts and technologies, Dr Helmut Richter. The same concept, which involves a "full LP [low-pressure] system redesign", according to Richter, is also being proposed for other regional jet projects including Bombardier's BRJ-X family and Fairchild Aerospace's 928JET.
The major difference in the proposed -50 rests with the fan, increased in diameter to 1.12m (50in) , compared to a diameter of 1.08m for the BR710. The -50 would generate more than 18,000lb thrust without significantly increasing engine size and compromising the ground clearance of the designs, which all have under-wing mounted engines.
The fan size change was needed because "the BR710 begins to run out of thrust at around 90 seats, and issues of time on wing may suffer", says Nico Bucholz, senior vice-president, commercial. "The BR715 would be complete overkill for a 70-seater. So we are proposing this blend of the BR710 and BR715." Despite the challenges, Bucholz adds, "we are very confident we can meet Embraer's entry-into-service target of 2003".
BMW Rolls-Royce is also awaiting a response from Airbus for bids made with another proposed derivative - a 6,700-9,000kW (9,000-12,000shp) turboprop dubbed the BR700-TP. The engine is competing against a combined Snecma-MTU engine called the M138 and a "twin-pack" (two engines driving a single propeller) solution from Pratt & Whitney Canada based on the PW150 and aimed at the A400M, or European FLA (Future Large Aircraft) military transporter.
"We are well in the race," says Nittinger who adds that its partner on the project, Rolls-Royce Allison, could be changed for another European-based propeller-gearbox specialist if its bid is selected. The first engine run is provisionally scheduled for mid-2000, with certification in 2002 and entry into service by the end of 2004.
For the more distant future, BMW Rolls-Royce is involved in the German E3E (economy, efficiency and environment) core demonstrator programme with MTU. Although aimed initially at reducing emissions and improving efficiency, the E3E could provide a platform for an all-new BR700 derivative from 2007 onwards.
An early version of the proposed E3E core has just made its first run at a test stand at the University of Stuttgart and, pending successful results, will be used to help define the remaining design of the new core which will run in late 2000. The E3E is a follow-on effort to a joint industry, Government research effort which ended last year with the running of a low- emission combustor on a BR715.
"Noise and emissions are the key," says Nittinger, who adds that a production version of the staged combustor could be retrofitted into existing BR700 engines from 2002 onwards. The new combustor reduces emissions of nitrous oxides by 20% compared to the current BR715, therefore making it around 50% below current standards.
A follow-on test phase, later this year, is expected to see testing of an advanced, nine-stage HP compressor developed using three-dimensional aerodynamic design techniques. The new compressor could result in pressure ratios as high as 25:1, producing stage loadings similar to those of the P&W PW6000. MTU is contributing to the design and test of the HP compressor. The combined effect of these programmes and developments is a sensation of quiet optimism at BMW Rolls-Royce. With expansion under way, and several irons in the fire, it seems certain that the fledgling and ambitious engine maker is set to celebrate its 10th anniversary in July 2000 in style.
Source: Flight International