It was initially powered by the Sunbeam Arab, but the third prototype was used as a testbed for the Cosmos Mercury, marking the start of Roy Fedden's association with the Bristol Aeroplane Company.

Ailerons were carried only on the upper planes and there were smooth cutouts in both to improve the view from the open cockpit, placed just behind the trailing edge.

The water-cooled V-8 Arab engine allowed a smooth and quite short installation, ending in a two-blade propeller and conical spinner.

[2] It was installed inside a low-drag cowling with exposed cylinder heads, making the aircraft 10 in (250 mm) shorter than the Arab-powered machines.

The Armistice brought an end to the Mercury contract, the cancellation of the two outstanding Scout Fs, and the abandonment of hopes of its production.