Anton J Landgrebe

US Patent:

57881910, Aug 4, 1998

Filed:

Aug 18, 1995

Appl. No.:

8/517026

Inventors:

Brian E. Wake - Portland CT
T. Alan Egolf - Glastonbury CT
Peter F. Lorber - Coventry CT
Anton J. Landgrebe - South Windsor CT

Assignee:

Sikorsky Aircraft Corporation - Stratford CT

International Classification:

B64C 2306

US Classification:

244199

Abstract:

In one embodiment for a helicopter main rotor assembly, a half-plow vortex generator is mounted in combination with the upper aerodynamic surface of each main rotor blade and is operative to generate a primary corotating vortex of sufficient strength to interact with and accelerate the dissipation of the tip vortex generated by the same main rotor blade, thereby reducing blade-vortex interaction noise radiating from the helicopter main rotor assembly. The half-plow vortex generator has a right triangular planform configuration defined by a length, a width, and an apex angle. The three-dimensional configuration of the vortex generator is further defined by an apex height. The apex height is the primary determinant of the strength of the generated primary corotating vortex and is defined in terms of the thickness of the main rotor blade at the local chord where the vortex generator is mounted. The apex height may be approximately equal to the local thickness, but preferably has a magnitude within the range of about one-eighth to about three-quarters of the local thickness. The length, width, and apex angle are secondary determinants of the strength of the primary corotating vortex generated by the half-plow vortex generator.

US Patent:

57852820, Jul 28, 1998

Filed:

Aug 7, 1996

Appl. No.:

8/693579

Inventors:

Brian E. Wake - Portland CT
Peter F. Lorber - Coventry CT
Anton J. Landgrebe - South Windsor CT

Assignee:

Sikorsky Aircraft Corporation - Stratford CT

International Classification:

B64C 2300

US Classification:

244199

Abstract:

In one embodiment for a helicopter main rotor assembly, a half-plow vortex generator is mounted in combination with the upper aerodynamic surface of each main rotor blade and is operative to generate a primary corotating vortex of sufficient strength to interact with and dissipate the tip vortex generated by the same main rotor blade, thereby reducing blade-vortex interaction noise radiating from the helicopter main rotor assembly. The half-plow vortex generator has a right triangular planform configuration defined by a length, a width, and an apex angle. The three-dimensional configuration of the vortex generator is further defined by an apex height. The apex height is the primary determinant of the strength of the generated primary corotating vortex and is defined in terms of the magnitude of the local chord where the vortex generator is mounted. The apex height preferably has a magnitude within the range of about 0. 01 to about 0.