Robert D Cuthbertson

US Patent:

41563441, May 29, 1979

Filed:

Dec 27, 1976

Appl. No.:

5/754138

Inventors:

Robert D. Cuthbertson - Kirkland WA
Larry A. Schaut - Seattle WA

Assignee:

The Boeing Company - Seattle WA

International Classification:

F02K 306

US Classification:

60226R

Abstract:

This invention is an improvement to a turbofan engine intended to reduce fan noise caused by the interaction of the rotor with secondary flow generated by the inlet guide vanes. A portion of the air flowing through the engine is removed from the fan duct from a region between the inlet guide vanes and the rotor and near the outer periphery of the fan duct by a system of bleed ducts. The ducts have one or more openings in the fan casing. The system may also include means for controlling the flow through the bleed ducts and means for injecting high energy flow into the bleed ducts to assist in ejecting the bleed flow.