Design and Test of a Mach Scale Swashplateless Rotor Using Smart Trailing-Edge Flaps

This paper presents the development of an articulated Mach scale swashplatesless rotor with on-blade actively controlled trailing-edge flaps. The baseline composite blade is designed and fabricated, nominally based on the UH-60 Black Hawk rotor. The parametric study shows blade pitch index and flap length are key parameters for the present swashplateless rotor. The primary parameters are determined as: blade pitch index 14.5°, flap length of 28% rotor radius, and flap width of 15% blade chord. Each trailing-edge flap is actuated using two eight-layer tapered PZT-5H bender actuators. A new procedure is developed to integrate the actuator/flap system to the baseline blade to minimize the fabrication and assembly process. A set of four-bladed swashplateless rotor is fabricated and bench-top tests are conducted to evaluate the performance of the fabricated bender actuators. The vacuum chamber rotating test shows that the Mach scale swashplateless system has a good structural integrity at the rotor speed of 2300 rpm. Hover tests are carried out to evaluate the system integrity of blade, and to perform functional check-outs of the test stand and the instrumentation.