Shake Test of a Propeller Test Rig in the 40- by 80-Foot Wind Tunnel

A shake test was conducted to determine the dynamic characteristics of a propeller test rig in the Ames 40- by 80-Foot Wind Tunnel. The rotor off hub transfer function (acceleration per unit force as a function of frequency) was measured in the longitudinal, lateral, and vertical directions for shaft angles of 0 and 90 deg corresponding to propeller and helicopter operation, respectively. The dynamic data are summarized for the configurations tested, giving the following properties for each mode identified: the natural frequency, the hub response at resonance, the damping coefficient, the damping ratio, and the modal mass. The complete transfer functions are presented, and the detailed test results are included.