Helicopter Sikorsky HRS-1 Serial 55-045 Register 127809 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127809 US Marine Corps 1951-07-16Sikorsky S-55 c/n 55-045, ff:? del USMC as HRS-1, 127809, 16Jul51 Send Updates Use APP to upload photo @ (optional) When Now? / / Send