At the start of the First World War, Vickers entered into a partnership with the Hart Engine Company to develop a 150 hp (110 kW) nine-cyliner radial engine designed by Hart. This engine was planned to power a number of new designs by Vickers, the first of which was a small single-engine pusher biplane fighter, the F.B.12. The F.B.12D was the final variation, only 1 prototype was produced with a larger 110 hp (80 kW) Le Rhone engine.