Helicopter Sikorsky HR2S-1 Serial 56-023 Register 140321 used by US Marine Corps USMC. Built 1957. Aircraft history and location Aircraft History 140321 US Marine Corps 1957-03-07Sikorsky S-56, c/n 56-023, ff:? del USMC as HR2S-1, 140321, 07Mar57 w/o unk. 1968-05-20soc 20may68 Send Updates Use APP to upload photo @ (optional) When Now? / / Send