A Quiet Engine for stilling complaints.

Abstract

Two experimental Quiet Engines using derated CF6 cores are discussed. One engine has a low-speed fan running at a tip speed of 1160 fps; the other engine has a fan running at the high speed of 1550 fps. The two engines are expected to show the relative advantages of fans operating at low tip speeds with high lift coefficients in comparison with fans operating at high tip speeds with low lift coefficients. Test results obtained with full-scale (6-ft diameter) fans are examined.