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O/T: Expensive gas giving Unducted fans a second chance?

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  • O/T: Expensive gas giving Unducted fans a second chance?

    New-Generation GE Open Rotor and Regional Jet Engine Demo Efforts Planned

    May 11, 2008
    By Guy Norris

    General Electric is joining with NASA to revive studies of its long-abandoned GE36 unducted fan, or "open rotor" and is simultaneously launching a next-generation CF34 technology effort as part of a pressing drive to develop families of fuel-saving engines.

    GE stresses that the two-pronged move, which throws down the gauntlet to Pratt & Whitney's geared turbofan (GTF) ambitions, is part of a long-term strategy that could lead to both open-rotor and advanced conventional turbofan demonstrators in the latter part of next decade.

    GE and NASA have signed a Space Act agreement covering studies of the open rotor concept, which offers the potential for up to 30% lower fuel burn compared with current engines. The NG34 technology plan, aimed at regional jets, has potential for up to 20% fuel savings.

    Under the cost-sharing Space Act deal with NASA, GE will refurbish all the original unducted fan (UDF) test rigs, and, with the agency, will begin a rigorous analysis of data collected during the $1.2-billion propfan program that ended almost 20 years ago. "We will then be looking at all the new technology that can be added to the system that ran back then, and at what the core would be like, the materials properties of the blades and the fan shapes," according to GE.

    The thrust of the open rotor study, which is still in the stages of being refined, is to overcome noise and mechanical complexity - two major hurdles that stymied the original propfan projects. Along with the GE36, an effort that also involved NASA, these included P&W/Allison's 578-DX ultra-high bypass demonstrator. Crucially, both programs produced significant fuel savings, but with prices at 65 cents per gallon toward the end of the demo phases, this was not gauged sufficiently important to warrant further ııdevelopment.

    "Together with NASA [Glenn Research Center] we hope to look at counterrotating blades, and ways to take out mechanical complexity and noise." Previous data from the GE36, which was based around an F404 fighter engine driving two sets of variable-pitch fan blades, "have all been digitized," and will be run through modern 3D analytical tools to evaluate performance. "Using these tools will tell us much more from the same data than it gave us in the late 1980s," GE states.

    LINK to more information:
    Click HERE to read the full article at Aviationweek.com<---


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  • #2
    Re: O/T: Expensive gas giving Unducted fans a second chance?

    I´m seeing the future Unlimited Red Baron or Precious Metal with one of those 3000-4000HP unducted contra-rotating props.
    There are original NASA reports, in the NASA web page, about the UDF (not posted here because their size) which identification numbers are ID 19900000731 / ...732 and ...733.
    Thank you AirDOGGe for posting this news

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