W27

The W-27 was the warhead derivative of the first lightweight thermonuclear bomb, which began development in May 1955. Twenty warheads were produced. The W-27 weighed 2,800 lbs. and had a yield of several megatons. The decision to use the W-27 warhead necessitated the only major structural change in the Regulus I design. The nose section of the tactical missile was redesigned with a "bulged chin" to accommodate either the long and narrow W-27 or the spherical W-5. The W-27 was finally retired in July 1965.