Helicopter Sikorsky HRS-1 Serial 55-018 Register 127784 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127784 US Marine Corps 1951-04-02Sikorsky S-55 c/n 55-018, ff:? del USMC as HRS-1, 127784, 02Apr51 1952-05-27 w/o 27may52 at Hapsu, Korea Send Updates Use APP to upload photo @ (optional) When Now? / / Send