Why CFM’s Open-Fan Engine Must Solve The Acoustic Problem That Killed GE’s 1980s Open-Rotor Program

The headline figure attached to CFM International’s RISE program is easy to understand; more than 20% lower fuel burn than today’s best narrowbody engines would represent one of the largest efficiency improvements seen in commercial aviation for decades. In an industry facing mounting pressure to cut emissions without sacrificing growth, that number alone explains why airlines, manufacturers, and regulators are paying close attention to the project.