CFD Based Aerodynamic Design of Helicopter Tail Boom for Hover and Sideward Flight Performance Enhancement

Abstract

Aerodynamic shape design of the helicopter tail boom is aimed for anti-torque power requirement alleviation at hover and improvements on sideward flight characteristics. Oval type basic tail boom cross section, whose camber can be modifiable with organic shaped strakes, is proposed to supersede conventional symmetrical tail boom profiles. Performance of several contour shapes is investigated with systematically varying the position and alignment of the strakes through the 2-D RANS simulations. Cross-section shapes that shows highest potential are utilized on tail boom design and to evaluate the resulting hover performance, 3-D CFD analyses are conducted with both of RANS simulations using the actuator disk approach and URANS solutions where blade motions are modeled with overset method. The assessment of the design concept outlined that, utilizing proper design decisions on position, size and alignment of the strake shapes on properly designed oval type cross section, it may be possible to reduce significant amount of power requirement on hover while enhancing the lateral controllability margins at sideward flight or hover at cross wind conditions.