APPARATUS AND METHOD FOR REDUCING TURBOPROP NOISE

摘要

An apparatus and method for reducing noise within the fuselage of a propeller driven aircraft (20). In one embodiment the propeller blades (38) are spaced apart and in front of an offset inlet (48). The inlet (48) provides air to a gas turbine engine (58) powering the propeller (32), and also to a scavenge duct (60). The propeller blades (38) and inlet (48) are spaced apart such that during cruise conditions for the aircraft, the trailing edge (54) of the propeller blades are spaced apart from the inlet by more than one-fourth of the chord length (55) of the propeller blades (38), and less than about the chord length of the propeller blades. In another embodiment, the scavenge duct (60) is constructed to flow an increased amount of air. In this second embodiment, the engine duct (56) flows more than about 40 % of the total amount of air entering the inlet duct (48), and less than about 60 % of that total airflow.