Helicopter anti-torque system using fuselage strakes

US4708305A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Henry L. Kelley · Newport News, US
• John C. Wilson · Rochester, US

Key dates

• Filing date: Jan 30, 1987
• Grant date: Nov 24, 1987
• Expiry date: Jan 30, 2007

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B64C2027/8245
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A helicopter 10 with a system for controlling mainrotor torque which reduces the power and size requirements of conventional anti-torque means. The torque countering forces are generated by disrupting the main rotor downwash flowing around the fuselage. The downward flow is separated from the fuselage surface 11 by strakes 16 and 17 positioned at specified locations on the fuselage 11. These locations are determined by the particular helicopter wash pattern and fuselage configuration, generally being located 30.degree. before top dead center 21 and 30.degree. from bottom dead center 22 on the fuselage side to which the main rotor blade 12 approaches during rotation. The strakes 16 and 17 extend along the fuselage 11 from the cabin section 18 to the aft end and can be continuous or separated for aerodynamic surfaces such as a horizontal stabilizer 15.