The new design, given the company designation B.48, was known unofficially by Blackburn as the "Firecrest" but was always known by S.28/43, the Air Ministry specification. It was a low-winged, single-seat, all-metal monoplane. Aft of the cockpit the fuselage was an oval-shaped stressed-skin semi-monocoque, but forward it had a circular-section, tubular-steel frame.
The new design, designated by the company as B.48, was known colloquially by Blackburn as the "Firecrest" but retained its official designation as S.28/43 under Air Ministry specification. It featured a low-winged, single-seat, all-metal monoplane configuration with an oval-shaped fuselage aft of the cockpit and a circular-section frame forward.