Patent ID: 7926760
Filing Date: 2011-04-19
Classification: B64C,B64D

Abstract:
1. An aircraft with reduced environmental impact, the aircraft comprising: a fuselage provided with two symmetrical wings and a rear horizontal stabilizer; a turboprop with two contra-rotating propellers mounted at the rear of the aircraft, the axis of said turboprop substantially parallel to the longitudinal axis of said aircraft, wherein: a first conical lobe, defining amplitude with respect to spatial position, of interaction noise from said contra-rotating propellers is directed toward the front of said turboprop and centered on the axis of the turboprop, the vertex of said first conical lobe is approximately midway between geometric planes of said propellers, said first conical lobe disposed between a first external conical surface having an angle of 50° to 70° from the axis of said turboprop and a first internal conical surface having an angle of 20° to 40° from the axis of said turboprop, said first external and internal conical surfaces being coaxial with said turboprop and having the same vertices as that of said first conical lobe; and a second conical lobe, defining amplitude with respect to spatial position, of the interaction noise from said contra-rotating propellers is directed toward the rear of said turboprop and centered on the axis of the turboprop, the vertex of said second conical lobe is approximately midway between the geometric planes of said propellers, said second conical lobe disposed between a second external conical surface having an angle of 40° to 60° from the axis of said turboprop and a second internal conical surface having an angle of 10° to 30° from the axis of said turboprop, said second external and internal conical surfaces being coaxial with said turboprop and having the same vertices as that of said second conical lobe; and said turboprop is disposed on the back of said aircraft, between said wings and said horizontal stabilizer, so that the bottom portion of said first conical lobe encounters said wings and the bottom portion of said second conical lobe encounters said horizontal stabilizer.