Several warheads were available for use in the Regulus I tactical missile:

  • MK5 – The MK5 Mod 0 (W-5-0) warhead was placed into production in April 1954.  The W-5 weighed 3,000 lbs. and had a yield between 40-50 KT, depending on the nuclear components selected.
  • XW-8/Regulus – The Mk-8 was a derivative of the earlier “Little Boy” gravity bomb. On February 15, 1951 authorization was given by the AEC to develop the XW-8/Regulus warhead.  Only one flight test was conducted, and the warhead work was suspended in May 1955, when the Navy decided to investigate thermonuclear warheads for Regulus.
  • W-27 – 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.

More Regulus I:

General Characteristics for an Interim Guided Missile
Able, Backer, Charlie and FTV-1
Operation Splash and FTV-3
Regulus I and II
Regulus I Subsystems
Airframe, Engine and Fuel Systems
Autopilot, Radio Control, Guidance and Instrumentation
Landing Gear and Hydraulic Systems
Nose Boom, Wing and Fin Fold
Launch Slippers, Parabrake, Smoke Systems and Jato
Interesting Statistics