| Boulton Paul Balliol | |
|---|---|
 Balliol T.2 in 1955 | |
| General information | |
| Type | Two-seat Trainer |
| Manufacturer | Boulton Paul Aircraft |
| Designer | |
| Status | Retired |
| Primary users | Royal Air Force |
| Number built | 229 |
| History | |
| Introduction date | 1950 |
| First flight | 30 May 1947 |
The Boulton Paul Balliol and Sea Balliol are monoplane advanced trainer aircraft designed and produced by the British aircraft manufacturer Boulton Paul Aircraft. On 17 May 1948, it became the world's first single-engined turboprop aircraft to fly.[1] The Balliol was operated primarily by both the Royal Air Force (RAF) and the Royal Navy Fleet Air Arm (FAA).
Developed during the late 1940s, the Balliol was designed to fulfil Air Ministry Specification T.7/45, replacing the wartime North American Harvard trainer. Unlike previous trainer aircraft, which were powered by piston engines, it was specified for the aircraft to use newly developed turboprop propulsion instead. On 30 May 1947, the Balliol performed its maiden flight; the first preproduction aircraft would fly during the following year. Production examples were powered by the Rolls-Royce Merlin engine, while various prototypes and pre-production aircraft featured alternative powerplants such as the Rolls-Royce Dart and Armstrong Siddeley Mamba turboprop engines.
The Balliol entered service with the RAF in 1950 and proved to be a relatively trouble-free trainer. However, a shift in attitudes towards turbojet-powered trainer aircraft would see orders being curtailed for the type by 1952. Despite this, a navalised version of the aircraft, the Sea Balliol, was also introduced for deck landing training. The type also saw some use in other capacities, such as for experimental flights. Only a single export customer, the Royal Ceylon Air Force, would procure the type.