Pratt & Whitney TF33 (JT3D)
The TF33 (JT3D) is a turbofan version of the J57 turbojet. The first two
compressor stages of the cancelled J91/JT9 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 15-22 percent.