Helicopter Sikorsky HRS-3 Serial 55-450 Register 137841 used by US Navy USN. Built 1953. Aircraft history and location Aircraft History 137841 US Navy 1953-06-04Sikorsky S-55 c/n 55-450, ff:? del USN as HRS-3, 137841, 04Jun53. Send Updates Use APP to upload photo @ (optional) When Now? / / Send