Original URL:
http://www.theregister.co.uk/2009/06/12/nasa_open_rotor_trials/
NASA working on 'open rotor' green (but loud) jets  Want to save
the planet? Put up with noisier airports  By Lewis Page  Posted
in Science, 12th June 2009 12:56 GMT  NASA and General Electric
have teamed up with French industry to revive a type of fuel-
efficient aircraft engine shelved in the 1980s, in an effort to
tackle aviation carbon emissions and high fuel costs.  The "open
rotor" engines, despite their relatively green characteristics,
will still be unpopular with many anti-aviation campaigners as
they are significantly noisier than ordinary turbofans.  New
open rotor engines, as envisaged by Rolls Royce  Sound and fury,
signifying green?  Open rotor engines work in a fashion not
dissimilar to today's high-bypass turbofans, which use a central
gas-turbine core to drive a larger-diameter fan which rams a lot
more air through the outer part of the engine ("bypassing" the
central jet, hence the name). This makes for much better