Helicopter Sikorsky HRS-3 Serial 55-435 Register 137837 used by US Marine Corps USMC. Built 1953. Aircraft history and location Aircraft History 137837 US Marine Corps 1953-05-13Sikorsky S-55 c/n 55-435, ff:? del USMC as HRS-3, 137837, 13May53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send