Westland, in conjunction with the Cierva Company and M. Lepere, produced the C.L.20 Autogiro, a two-seat side-by-side cabin machine. Lepere was at that time working with Liore and Olivier, holders of the Cierva licences for France. The fuselage was of welded seamless steel tubing, triangulated and faired to a streamline form by the use of stringers and fabric covering. A large door was fitted on either side of the cockpit and transparent panels, running right down to the bottom longeron, gave a forward and downward range of vision. The three-blade direct control rotor was arranged to fold, to facilitate parking and storage. It had a rotor with a direct-control head consisted of three untapered blades on flapping and drag hinges. Three vertical fins gave directional stability, while the tailplane was designed so that the aerofoil section of one half was inverted, and set at a negative angle of incidence, to counteract airscrew torque.
The earliest flights were in 1935.This experimental aircraft was successfully flight-tested by the Cierva Company's pilot, R. A. C. Brie, but the shadow of impending hostilities prevented its production in quantity and closed Westland interest and activity in autogiros.
Engine: One 90hp Pobjoy Niagara S
Rotor diameter: 9.75m
Loaded weight: 635kg
Empty weight: 381kg
Landing speed: 40km/h