The Bristol twin rotor helicopters were intended to provide a viable civil and military transport rotorcraft during the post-war years. The Type 173, capable of carrying 14 passengers, flew successfully in 1952 and was subsequently tested with stub wings to offload the rotors.
The turbine-powered Type 192 was larger and entered service with the Royal Air Force as the Belvedere, operating in Malaya and Aden. The Belvedere remained in service until 1969.
The whole concept of the Bristol twin rotor helicopters was led by pioneer Raoul Hafner, including the winged compound experiments.