Helicopter reduced vibration axial support struts and aircraft suspension system are disclosed with at least one vibration controlling fluid containing strut. The powered struts include an outer rigid housing (28) containing an inner rigid member (32) and first (62) and second (64) variable volume fluid chambers. Fluid pressure differentials are created between the first and second variable volume fluid chambers to control motion between the strut ends. The powered fluid containing struts, support isolators, suspension systems, and methods of operation provide reduced helicopter aircraft vibrations.