PhotogaleriesREGULUS II gallery 2018-09-172020-09-29 Javier Regulus II missile was clearly superior to the first model, with a flight ceiling of more than 18,000 meters, a speed of Mach 2 and a range of 2,200 km. The landing gear was only mounted on the missiles used for the tests. A class of nuclear submarines was projected to carry and launch this missile, but only one was completed, the USS Halibut, which was later transformed to use the Regulus I missile. The other 3 submarines in the class were canceled and their names were gave to ships of the Thresher class. Regulus II had a solid fuel booster engine with 51,750 or 60,750 kg of thrust and one for the flight with 6,750 kg of thrust. Its warhead was the 1Mt thermonuclear W-27 and an automated launcher system was installed experimentally on an LST-type vessel, the USS King County.