Helicopter Sikorsky HRS-1 Serial 55-039 Register 127804 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127804 US Marine Corps 1951-07-03Sikorsky S-55 c/n 55-039, ff:? del USMC as HRS-1, 127804, 03Jul51 Send Updates Use APP to upload photo @ (optional) When Now? / / Send