Work on the W.11 commenced in 1945. The original W.11 configuration used two rotors transversely mounted either side at the front of the fuselage and a single rotor mounted on the centerline at the tail. This configuration was tested in 1947 with a scale-model in a wind tunnel at the Royal Aircraft Establishment at Farnborough, and much useful data on its performance was acquired. This determined that a single rotor at the front and the pair at the back of the fuselage was preferred for optimum stability and control.