This paper demonstrates the ability of the Smart Spring to suppress helicopter blade vibration through numerical simulation and experimental investigation. Mechanical shaker tests on a Bell-212 helicopter blade section verified the impedance control properties and the ability to suppress blade vibration using the Smart Spring proof-of-concept hardware. More importantly, the tests conducted in a wind tunnel proved the performance of the Smart Spring under highly varying unsteady excitation conditions. These tests confirmed that the Smart Spring system is able to actively suppress helicopter vibration through adaptive control of blade impedance properties.