Helicopter Sikorsky HRS-3 Serial 55-921 Register 144246 used by US Navy USN. Built 1956. Aircraft history and location Aircraft History 144246 US Navy 1956-03-20Sikorsky S-55 c/n 55-921, ff:? del USN as HRS-3, 144246, 20Mar56. Send Updates Use APP to upload photo @ (optional) When Now? / / Send