J57 is a type of jet engine developed by General Electric in the 1950s. It was primarily used in military aircraft, including the McDonnell Douglas F-4 Phantom II. The engine is known for its high thrust and reliability, making it a popular choice for various fighter jets. The J57 engine features a turbojet design, which allows it to efficiently produce power for supersonic flight. It has been utilized in several aircraft models and has contributed to advancements in aviation technology, influencing the design of future engines in both military and civilian aviation sectors.