On their own initiative, Vertol developed a turbine powered version of their Model 44 (H-21) as the Model 107 prototype, (c/n 69-1X) registered N74060. The US Army was so impressed that it ordered ten improved versions of the Vertol Model 107 as the YHC-1A. At the same time, it also asked Vertol to develop a larger version as the YHC-1B. Vertol began development of this larger version as the Model 114. To fund the development of the Model 114, the Army canceled seven unstarted YHC-1As (Vertol 107) and shifted the funds to build five YHC-1B prototypes (Model 114). Three YHC-1As were built for the Army; including: 58-5514, 58-5515, & 58-5516. One (58-5514) was modified into the first civil BV-107II-2 passenger prototype (c/n #1?). One (58-5515) was bailed to NASA in late 1962 and registered as NASA 533. NASA 533 first served at the Dryden Research Center (i.e. Edwards AFB) then moved to the Wallops Island Flight Center until replaced by a CH-47B for conducting automatic landing tests. The last one (58-5516) was modified into the BV-107M prototype for US Navy & Marine Corps evaluation, maintaining its Army serial number. In 1962, the designation of all three aircraft was changed to YCH-46C
, then later to CH-46C
. The fate of all three aircraft is unknown.