Snecma’s Silvercrest turbofan family a challenger in 10,000-lb-thrust class

 - November 6, 2006, 8:55 AM

Engine manufacturers are gearing up for development programs aimed at bringing new generations of 10,000-pound-thrust turbofans to business aviation. Silvercrest, the first of Snecma’s new family of such engines for midsize to large business jets and 40- to 60-seat regional airliners, makes its world debut here with its new name and newly revealed specs.

The Safran subsidiary announced last January that it was developing a state-of-the-art turbofan code-named SM-X for entry into the market around 2010. Now the cat’s out of the bag and the so-called Silvercrest program is a go.

The development is part of Snecma’s strategy to gain market share with commercial engines for aircraft with fewer than 100 seats and follows the recent launch of the SaM 146 engine for Sukhoi’s future Russian Regional Jet, now known as the Superjet 100.

According to Snecma executive vice president of commercial engines Jean-Pierre Cojean, the name Silvercrest “reflects the classy nature of the business and the technical nature of business jet technology. ‘Silver’ symbolizes the high class of the business and ‘crest’ has a connotation of altitude and the environment as owners will be able to sustain the next stage or two of environmental rules.”

Big Power in Small Package

The turbofan, he said, is not a scaled-down design or a derivative of the CFM56 that Snecma produces under its 50-50 CFM International partnership with General Electric, nor is it an offshoot of the SaM146 program currently under way, although it shares some key technologies with that engine.

“We have been producing engines for 50 years but are learning what airframers want from us as new boys on the block with big powerplant technology applied to a small engine,” Cojean said. “We have to assume we will be innovative enough to be selected on several platforms.” A business aviation engine is being developed first and the regional jet engine will come later, he said.

“The engines will have their own specific architecture, optimized for the requirements of business jets and smaller regional jets. It will be a new entry for service around 2010 and, with our up-to-date technology, we hope to take a good share of this market,” he said.

Snecma is considering a thrust range of 8,000 to 10,500 pounds for the engine. The first turbofan will be at the lower end of the thrust range. Cojean said the technologies used on the Silvercrest family of engines will deliver 5 to 15 percent better specific fuel consumption and lower emissions than the current generation of engines. He said he is confident the Silvercrest platform will fare well in a market already fiercely contested by GE, Rolls-Royce and Honeywell. He added that currently only the Allison AE3007 and General Electric CF34 are available in this thrust range and he believes the Silvercrest will be a “much better choice.”

Silvercrest will benefit from Snecma’s experience with the low-pressure CFM56 civil turbofan, which in various aircraft types has notched more than 300 million hours of flying time, and also from its military engine programs and the DEM21 core demonstrator. The DEM21 is at the heart of the 13,000- to 18,000-pound SaM146 turbofan currently under development in partnership with Russia’s NPO Saturn.

Cojean said, “By building on our technologies and expertise in the commercial engine market, we are now developing our own products in complementary segments. This is being launched on the SaM146 for a first application on a regional jet carrying 70 to 110 passengers, at 17,500 pounds of thrust.” Silvercrest will enable Snecma to offer propulsion systems for large and long-range business jets with mtows of 50,000 to 60,000 pounds, he said, as well as 40- to 60-seat regional jets. The engine’s core will feature a single-stage centrifugal compressor coupled with a four-stage axial compressor.

There is no state-of-the-art engine in this thrust segment in terms of architecture, fuel burn and cost of ownership, Cojean said. Silvercrest will feature exceptional climb and cruise thrust–at least 25 percent better than current engines–“as new business jets now demand this level of performance, particularly at maximum payload, hot days and for long-range flights.” Another important aspect of Silvercrest, he said, is a simplified design that “incorporates innovative solutions that drastically reduce the parts count, giving a significant reduction in maintenance costs for the operator.”

Partnerships a Possibility

Like all its commercial engine ventures, Snecma is considering inviting risk-sharing partners to join the program, according to the specific technology and market requirements of business aviation. Cojean stressed that Snecma is the only French engine company, but risk-sharing partners will not necessarily be only French. Italy’s Avio is involved in the design and construction of the core demonstrator that will lead to construction of the engine. Avio will focus on the combustor case for the core, participate in the design and manufacture of parts and carry out preliminary tests before delivering the combustor module to Snecma next June.

Snecma will pursue discussions with potential partners in parallel with the launch of the core demonstration phase but will maintain a leadership role on the powerplant’s development. The engine will be sold as a Snecma product and Snecma will hold at least 51 percent ownership of the project, he said. “We are initiating contacts for partners now and are confident we will find them. In fact, people are knocking on the door. It’s a nice situation to be in.”

Cojean said there is no relationship between Silvercrest and the new business jet, codenamed SMS, that Dassault chairman and CEO Charles Edelstenne last month said would be announced following the first quarter 2007 certification of the 7X trijet.

“We are talking to everyone who will require a 10,000-pound-thrust engine,” he said. “There is absolutely no combined strategy. If we power the new Dassault business jet, it will be because we have the best engine.”