Helicopter Sikorsky HRS-1 Serial 55-047 Register 127811 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127811 US Marine Corps 1951-07-25Sikorsky S-55 c/n 55-047, ff:? del USMC as HRS-1, 127811, 25Jul51 Send Updates Use APP to upload photo @ (optional) When Now? / / Send