Abstract: A shock strut employing fluid as a damping medium and gas trapped in a primary chamber above the fluid as a spring is modified by adding a secondary chamber with an orificed inlet to the primary chamber above the normal fluid level. For low velocity deflections of the strut, the gas can pass freely through the orifice so that the effective volume into which the gas is compressed is enlarged thereby reducing the spring rate. For high velocity deflections, the orifice meters the passage of the gas to the secondary chamber so that a higher spring rate is momentarily present. On extreme deflections, the fluid level within the strut reaches the orifice which severely restricts flow therethrough to cause a second greatly increased spring rate for the gaseous spring which also is velocity sensitive.