CFM GE/SNECMA

CFM International partners General Electric and Snecma have finalised the architecture of their Leap-X
turbofan, which is under development to equip the next-generation narrowbody replacements from Airbus and Boeing.

The engine is being designed for a possible service entry in 2016, offering a 16% reduction in fuel
burn compared with the best-selling CFM56, which it will eventually replace. However, there are widespread expectations that the airframers will not bring their new 150-seaters to the market before the end of the next decade.

"As the service entry date moves to the right, we get the benefit of that additional time to put more
efficient components into the engine," says Leap-X programme manager Ron Klapproth.

The Leap-X will have a bypass ratio of around 10, compared with 5-6 for the CFM56 family, and a core pressure ratio double that of the current engine, at 22. The powerplant will also feature a two-stage high-pressure turbine driving a 10-stage HP compressor, and the low-pressure turbine blades will be produced using ceramic matrix composite (CMC), says CFMI executive vice-president Olivier Savin.

The Leap-X core will undergo bench tests starting in mid-2009, and the first run of the full powerplant demonstrator is scheduled for 2012.

"We need to have the core on test a minimum of seven years before certification," says Klapproth.
The first phase of performance tests of Leap-X's 18-blade, 1.8m (71in)-diameter composite fan mounted on a CFM56-5C core at Villaroche in France are around two-thirds complete, with results "in line with predictions", says chief engineer Jerome Friedel. The fan demonstrator will be shipped to GE's Peebles facility later this year for acoustic and crosswind trials, before being returned to Villaroche for 5,000 cycles of endurance testing.

The composite fan and casing, produced using three-dimensional woven resin transfer molding, are expected to yield a weight saving per aircraft of more than 450kg (1,000lb), says Savin. The CMC LPT will save a further 150kg.

CFM International today will move the first LEAP-X engine core to GE Aviation's testbed at its Evendale, Ohio, facility to begin testing within three weeks as the GE/Snecma joint venture aggressively develops the new-generation powerplant it is marketing to Boeing and Airbus for the eventual successor to the 737 and A320 families.

CFM this week showed reporters both the core and a "MASCOT" test engine comprising composite three-dimensional modeling-designed LEAP-X fan blades currently undergoing crosswind tests at GE's Peebles, Ohio, facility. CFM said a baseline LEAP-X can be ready for certification by 2016 for a possible EIS in 2018 and insisted that it will be far enough along in development and testing by 2011-12 for the aircraft manufacturers to make a decision (ATWOnline, July 14).

"What is very important now is to conduct the development, to demonstrate all these technologies," CFM President and CEO Eric Bachelet told ATWOnline. "We are pushing the envelope on the core." He added that CFM is in "constant dialog" with Boeing and Airbus.

CFM officials described LEAP-X as a scaled-down widebody engine that can bring the kind of efficiencies generated by the GE90 and GEnx to the narrowbody segment, offering 16% lower fuel consumption than the CFM56-7 powering the 737NG. It is the result "of all the learning we've done over the last 15 years with widebodies," CFM Executive VP Chaker Chahrour said. It will have a 10:1 bypass ratio, twice that of the CFM56 and on par with a GE90 or GEnx.

The challenge, he added, is to achieve a similar reliability with a "workhorse" narrowbody flying multiple times daily to a GE90 powering a 777 flying one or two long-haul routes daily.

He said the LEAP-X will "maintain today's [CFM-56] maintenance costs."

Chahrour explained that the core going into the testbed will undergo a series of carefully monitored tests over the next two years (more than 2,000 sensors will be attached to it) and the next demonstration core will be built by mid-2011 with a third coming 6-8 months later.

The MASCOT simultaneously will test the 71-in.-diameter fan blades shaped with "woven resin transfer modeling" materials that are 1/3 the density of CFM56 blades.

Beyond 2012, "going forward is really going to be a function of what the airplane guys do," he said. "Six months ago, I would have said Airbus and Boeing would introduce a new [narrowbody] by 2018. I don't know that I can say that today. . .If the airplane companies haven't decided what to do [by 2012], we may have to sit back and wait."

Bachelet added, "A lot of it will depend on the evolution of fuel prices." Chahrour noted that even if Airbus and Boeing push off a decision, the LEAP-X is "applicable to the regional jet market. . .It's actually pretty easy to scale down the core."
by Aaron Karp

Mais GE / Safran-SNECMA sont en train de faire les 'lièvres' des motoristes rivaux !

Mizeke a écrit:Bonjour,

A propos de LEAP X et Mascot (Moteur A Souflante COmposite Taille) :

CFM Executive VP Chahrour a declaré “the LEAP-X will "maintain today's [CFM-56] maintenance costs”; ( par rapport au 56-7 ?)

Après avoir prédit une réduction de 16% de consommation.

J’ai lu de travers ou ça cloche quelque part.

Plus loin, M. Bachelet dit « cela dépendra de l’évolution des prix carburant » et M. Charhour d’ajouter
« Même si Airbus et Boeing repoussent leur décision [ de lancer un nouveau narrowbody ] le LEAP X
est prêt pour une application au marché des Regional Jets »

La notion de RJ, on a pu le voir ici et là, est mouvante ( capa qui monte à 85 / 125 sièges dans touts les projets lancés ou à lancer )

Et la déclaration se termine par « It's actually pretty easy to scale down the core”

En quoi le CFM 56 LEAP X core est scalable ?

On note bien que pas un mot n’est écrit sur les programmes des concurrents. Par élégance ou par antagonisme de "concepts" ?

Un pari sur l’échec du P&W Pure power 1000 ?

Est-ce que la différence se réduit (même si elle semble donc être essentielle) à l’opposition 2 axes contre 3 axes ?

CFM studies Airbus-specific variant of CFM56 engine
By John Croft

CFM continues to study a more efficient variant of its Airbus A320 family turbofan engine, the CFM56-5B.

The advances will be based in part on progress to date on the CFM56-7B Evolution turbofan, an upgrade of the CFM56-7B engine powering Next-Generation Boeing 737s. The newest 737, which will include aerodynamic improvements and a new Boeing "sky" interior, is set for entry into service in June 2011. ATI reported in May that Airbus and CFM had begun discussing the upgrade.

The CFM56-7BE engine has 9% fewer aerofoils as well as reshaped blades and vanes in the high- and low-pressure turbines to increase airflow through the engine and reduce operating temperatures. Combined with Boeing-designed modifications to the engine nozzle and plug, the engine will deliver 1% improvement in specific fuel consumption and 4% less maintenance costs. For the airframe in total, Boeing is advertising a 2% decrease in fuel consumption.

Boeing programs director at CFM Kris Shepherd says engineers are "trying to overshoot" the 1% target for the engine "a little bit to get some margin". In-flight data on the new engine will be available soon, as CFM 50/50 partner GE plans to begin flying a prototype on its 747-100 testbed in the US in February. Tests are expected to be complete in March, after which Boeing will begin testing the -7BE for the US Navy's P-8A Poseidon application, a variant of the Boeing 737-800.

In parallel, partner Snecma is now running "block tests" of severe operating conditions with an engine on a test stand at its facilities in France. "If it's going to break, this is when it's going to happen," says Shepherd of the Snecma tests. Included is a simulation of 150 consecutive take off and landing sequences, with the engine running as hot and fast as possible.

Shepherd says CFM has "been in discussions" with Airbus regarding a CFM56-5B evolution engine for the A320 family. Though some of the -7BE's low-pressure turbine technologies are already included in the -5B models, Shepherd says other possible changes will lead to further improvements of the engine. "It's too preliminary to talk about," he adds.