The Short SA.4 Sperrin was a British jet bomber design of the early 1950s. Built by Short Brothers it was viewed as a fall-back option in case the more advanced strategic bomber aircraft, then in development to equip the Royal Air Force's nuclear-armed V bomber force, experienced delays.
A total of four firms submitted tenders to meet the B.14/46 specification, Shorts' submission was selected as it had been judged to be superior. As the Sperrin was considered to be a possible production aircraft early on, a decision was taken for the two prototypes to be constructed.
Many design elements of the Sperrin had more in common with aircraft of the Second World War than those of the new jet age. The design was relatively straightforward in most aspects, with the exceptions of the flight controls and the unusual engine arrangement: The engines were mounted in pairs in nacelles mid-wing, one engine being stacked above the other.
The first prototype powered by four Rolls-Royce Avon RA.2 engines of 6,000 lbf (27 kN) of thrust and piloted by Tom Brooke-Smith, had its maiden flight on 10 August 1951.
The Sperrin was not put into production because the V bombers swept-wing designs. However, the two Sperrins were used in a variety of research trials through the 1950s, including engine tests using VX158 as a testbed for the de Havilland Gyron turbojet.
The two aircraft completed were retired in the late 1950s and ultimately scrapped sometime thereafter.