Helicopter Sikorsky HRS-1 Serial 55-080 Register 127840 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127840 US Marine Corps 1951-11-30Sikorsky S-55 c/n 55-080, ff:? del USMC as HRS-1, 127840, 30Nov51 Send Updates Use APP to upload photo @ (optional) When Now? / / Send