TF33 (JT3D) is a turbofan version of the J57
turbojet. The first two compressor stages of the canceled
replaced the first three compressor stages of the J57, making it
simple to modify existing turbojets with a kit. The
conversion increased thrust by 35 percent and fuel consumption by
The TF33 first flew in 1958 and was in production
until 1985. About 8,600 were produced.