Ovate loop for rotary-wing blades

• Main Authors: EGOLF T. ALAN, WAKE BRIAN E
• Format: Patent
• Language: English
• Published: 17.07.2001
• Edition: 7
• Subjects: AEROPLANES; AIRCRAFT; AVIATION; COSMONAUTICS; HELICOPTERS; PERFORMING OPERATIONS; TRANSPORTING

Blade vortex interaction (BVI) noise, associated with the operation of aircraft having rotary-wing blades, is abated by the inclusion of an ovate loop tip (20) at the tip portion (16) of each of the rotary wing blades. The ovate loop tip (20) is substantially ovate in shape transverse to the direction of rotation of the rotary-wing blades (12). The ovate loop tip (20) includes upper and lower halves (20',20'') of similar or substantially identical geometry, and is positioned substantially symmetrically with respect to a plane (24) defined substantially by the chord of the rotary-wing blade at or near the tip portion (16). The upper and lower halves (20',20'') of the ovate loop tip (20) have a common origin or root at their point of attachment with the blade tip portion (16). This geometry and positioning of the ovate loop tip (20) reduces the intensity of the resulting tip vortex, while also minimizing additional loads and stresses on the blade.