Helicopter Sikorsky HRS-1 Serial 55-048 Register 127812 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127812 US Marine Corps 1951-09-19Sikorsky S-55 c/n 55-048, ff:? del USMC as HRS-1, 127812, 19Sep51 1958-02 soc Feb58 Send Updates Use APP to upload photo @ (optional) When Now? / / Send