Helicopter Sikorsky HRS-1 Serial 55-020 Register N9013R XB-WAV N4779S 127786 used by US Marine Corps USMC. Built 1951. Aircraft history and location Aircraft History 127786 US Marine Corps 1951-04-02Sikorsky S-55 c/n 55-020, ff:? del USMC as HRS-1, 127786, 02Apr51 N4779S - ex 127786 XB-WAV - ex N4779S N9013R - ex XB-WAV Send Updates Use APP to upload photo @ (optional) When Now? / / Send