Helicopter Sikorsky HRS-1 Serial 55-074 Register 127836 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127836 US Marine Corps 1951-11-02Sikorsky S-55 c/n 55-074, ff:? del USMC as HRS-1, 127836, 02Nov51 Send Updates Use APP to upload photo @ (optional) When Now? / / Send