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The Blackburn Sprat was a small two seat biplane designed as an advanced trainer, but that never progressed beyond the prototype stage.
The Sprat was designed in response to Air Ministry Specification 5/24, for a small two-seat aircraft with interchangeable wheels and float undercarriage, for use as an advanced trainer with the RAF, on seaplane conversion courses and for deck landing practice in the Fleet Air Arm. Good deck flying characteristics were required on low power, with good take-off acceleration, low stalling speeds and good low speed controllability. A large number of designs were submitted and in September 1925 prototypes were ordered of the Blackburn T.R.1 Sprat, Vickers Type 1290 Vendace I and Parnall Perch.
The Sprat was designed by Major Bumpus, and was a smaller version of the Blackburn Velos two seat trainer, with a similar shape to the fuselage, wings and tail. It was powered by a 275hp Rolls-Royce Falcon III water cooled engine, but could also take a 240hp Siddeley Puma or 300hp ADC Nimbus. The engine was mounted in a self contained unit which could be removed by undoing four bolts. The engine mounting could then be used as an engine stand during maintenance. It was a single bay biplane with folding wings. The central section of the fuselage was built around a tubular steel framework. The rear fuselage was wooden with wire bracing. It had a wide track divided undercarriage with heavy duty rubber-in-compression main legs, and deck arrester claws designed to work with the fore-and-aft type of arrestor wires in use at the time. The undercarriage could quickly be removed and replaced with twin floats designed by Major J. D. Rennie which gave it excellent performance on the water.
Both of the cockpits were behind the trailing edge of the wing. The upper deck of the fuselage sloped down from the front cockpit to the engine to improve the view forwards. The student was in front with the instructor behind. Both cockpits had full controls, and the instructor could disconnect the student’s controls if required.
The Sprat made its maiden flight at Brough on 24 April 1926. It then went to the A&AEE at Martlesham Heath and the MAEE at Felixstowe for competitive trials. It lost out to the Vendance I, but the entire programme was then cancelled to save money, so none of the designs entered production. Despite not having been chosen, the Sprat was exhibited in the New Types Park at the Hendon RAF Display on 3 July 1926, and gave a flying display in which it performed well.
Engine: Rolls-Royce Falcon III
Power: 275hp
Crew: 3
Span: 34ft 9in
Length: 29ft 3in
Height: 11ft 0in
Tare weight: 2,318lb (landplane), 2,648lb (seaplane)
All-up weight: 3,220lb (landplane), 3,550lb (seaplane)
Max speed (landplane): 115mph at sea level, 112mph at 5,000ft
Max speed (seaplane): 112mph at sea level, 109mph at 5,000ft
Climb Rate: 1,100ft/ min (landplane), 937ft/ min (seaplane)
Service ceiling: 17,500ft (landplane), 15,700ft (seaplane)