The Rolls-Royce Spey is a turbofan engine designed for use in various military and civilian aircraft. Introduced in the 1960s, it is known for its reliability and efficiency, making it a popular choice for aircraft like the McDonnell Douglas DC-9 and the Hawker Siddeley Buccaneer. With a thrust range of approximately 12,000 to 22,000 pounds, the Spey engine features a two-spool design that enhances performance at different speeds. Its design has contributed to the success of several aircraft, showcasing the engineering prowess of Rolls-Royce in the aviation industry.