The Siddeley Viper is a small turbojet engine developed in the 1950s by Siddeley Engines, a British aerospace manufacturer. It was designed for use in various military and civilian aircraft, providing a compact and efficient power source. The Viper engine is known for its reliability and performance, making it suitable for a range of applications. This engine was notably used in aircraft such as the Hawker Siddeley Buccaneer and the De Havilland Sea Vixen. Its design features a single-spool configuration, which contributes to its lightweight and streamlined characteristics. The Siddeley Viper played a significant role in advancing jet propulsion technology during its time.