Herbert Smith designed a small single-bay biplane, powered by the 170 hp (127 kW) ABC Wasp radial engine.
An initial order was placed on 31 October 1917 for six prototypes with a conventional wood and fabric framework structure, but this was revised in November to fit two aircraft with a plywood monocoque fuselage.
[1] The first prototype, serial number C4284, with the conventional fuselage (which resulted in the designation Snail Mk.II) flew in April 1918.
[2] A second prototype (serial number C4288), with the monocoque fuselage (and thus designated Snail Mk.
Although performance was reasonable, being slightly faster than the Camel and climbing faster,[4] handling was poor, particularly at low speed, and as with the other Wasp engined fighters built to meet Specification A.1A, the Wasp engine proved unreliable,[1] with the competition being abandoned in October 1918.