In 1956, the U.S. Navy launched a new competition with the intent of meeting its requirements for a compact, all-weather multipurpose naval helicopter, encouraging private companies to submit their proposals. American manufacturer Kaman Aircraft Corporation decided to produce its own response for the competition, their submitted design, which was given the internal company designation of "K-20", was of a relatively conventional helicopter powered by a single General Electric T58-8F turboshaft engine which drove a 44-foot four-bladed main rotor and a four-bladed tail rotor. Following an evaluation of the designs that had been bid in response, the U.S. Navy decided to select the submission by Kaman to proceed with further development. Accordingly, in late 1957, Kaman was promptly awarded with a contract calling for the construction of four prototypes and an initial batch of 12 production helicopters, designated as the "HU2K-1".