Pratt & Whitney JT9D

The Pratt & Whitney JT9D was the first high bypass ratio jet engine to power a wide-body airliner and Pratt & Whitney's first high-bypass-ratio turbofan. The program was launched in September 1965 and the first engine was tested in December 1966. After FAA certification in May 1969 it entered service in January 1970 on the Boeing 747-100, the first jumbo jet, and it later powered the Boeing 767, the Airbus A300 and A310 and the McDonnell Douglas DC-10. It has a single-stage fan, a three-stage low-pressure compressor and an eleven-stage high-pressure compressor, and it used titanium and nickel alloys to improve fuel efficiency over the earlier JT3D. During the 747 flight tests the casing ovalized under takeoff stress and rubbed the turbine blade tips, so thirty aircraft waited outside the factory with concrete blocks hanging from their pylons until the casing was strengthened. Production ceased in 1990 and the PW4000 replaced it.