Helicopter Sikorsky HRS-1 Serial 55-077 Register 127837 used by US Navy USN. Built 1951. Aircraft history and location Aircraft History 127837 US Navy 1951-11-19Sikorsky S-55 c/n 55-077, ff:? del USN as HRS-1, 127837, 19Nov51 xfer NATC/Development Center, unk xfer NATC/Material Center, unk wfu unk. Send Updates Use APP to upload photo @ (optional) When Now? / / Send