Un résumé de Aviation week, sur ces futurs avions !
Rien de définitif, une compil des tendances connues !
Les motoriste et leurs apports bien présentés, rien de nouveau !
Merci à Keesje de A.net !
---------------------- Le Lien Aviation week ! Extrait de la part moteurs ----------------------------
CFM International, for example, will run its LeapX core around midyear. It will also be running tests of a full-scale resin-transfer-molding composite fan. LeapX is the CFM56 follow-on that the General Electric/Snecma joint ventureis designing, in part, with an eye on the next-generation single-aisle aircraft. The companies also are studying open-rotor designs.
One big question in the engine realm will be whether Pratt & Whitney and Rolls-Royce can agree on a way to maintain their International Aero Engines partnership, which now offers the V2500 for the A320 family. But Rolls and Pratt have very different ideas about the future engine, and so far there has been little indication that a consensus will be possible.
Pratt is betting heavily on its geared turbofan and last year started work on the Advanced GTF that would power the future Boeing or Airbus aircraft. The goal is to assess technologies and demonstrate them in 2012-13, says Bob Saia, Pratt's vice president for next generation products. To boost efficiency, the company wants to further advance its gear system from a 3:1 ratio to more than 4:1, says Saia, allowing the fan to run slower and thereby improving performance. The bypass ratio for that engine hasn't been set, but should surpass 12:1, while the engine pressure ratio should top 50:1, he adds.
Some of the Advanced GTF technologies could also be used to update new builds of the first-generation GTFs. Enhancements being explored include active combustor controls, advanced and lightweight materials, and advanced aerodynamics for the fan and compression system, as well as intelligent prognostic health management.
A 40,000-lb.-thrust-class GTF should be able to handle the likely size requirement for which Boeing and Airbus are striving, according to Saia. Airframers have indicated that aircraft size could range up to 250 seats. What remains unclear is whether a single engine or aircraft type will emerge to cover the short- to medium-haul sector.
Although novel aircraft configurations are largely associated with open rotors, Saia says the GTF could also be used for unorthodox aircraft designs, including forward-swept wings - which Airbus has been considering to improve laminar flow. One issue that Pratt will be assessing as it evaluates recent flight-test data (see p. 46) is how its critical fan-drive gear system would be affected by fuselage mounting or other installation options.
In the meantime, Rolls has been reluctant to narrow its design options, preferring to continue working on a two-shaft RB282 derivative configuration, a three-shaft RB285 and an open-rotor concept.
The open rotor should deliver around 15% improved specific fuel consumption over standard engines at a speed of roughly Mach 0.8. Rolls is pursuing a two-spool core with counterrotating propellers. Scale-model tests also have shown that one of the big concerns about open rotors - noise - can be overcome.
Trials in the Netherlands and U.K. suggest that an open-rotor-powered design can be made quieter than current-generation aircraft, says a Rolls official. The open-rotor configuration should be ready for service in 2018.
Rolls engineers hope to draw on a variety of research efforts to advance underlying technologies. While the European Clean Sky program focuses heavily on open rotors, other projects - including the U.K.-funded Environmentally Friendly Engine (using a Trent 1000) - focus on upgrading more traditional designs. The EFE demonstrator is now being built at Rolls-Royce's Bristol, England, facility, and it is slated to start running this year. Lessons from the program, including the lean-burn combustor, could still be fed into the TrentXWB, the latest Rolls engine being developed for the Airbus A350XWB, says the Rolls-Royce official.