Burnelli's designs were based on the idea that an airfoil-section fuselage could contribute to the lift generated.

The UB-14 had retractable landing gear and was powered by two Pratt & Whitney radial engines.

The first prototype, UB-14, was destroyed in a 1935 accident attributed to faulty maintenance on the aileron control system.

Burnelli applied to the CAA for approval to fly a transatlantic flight with Clyde Edward Pangborn as the pilot in September 1936,[3] however it failed its airworthiness certification due to an excessively long takeoff run and poor quality control.

[4]After appropriate work, in June 1941 Jim Mollison and an Air Transport Auxiliary crew delivered the Cunliffe-Owen OA-1, now registered as G-AFMB to Fort Lamy, Chad.