Advanced Jet Engine is a mod that provides realism for turbojet, turbofans, air-breathing rockets, propellers and rotors in KSP. If you're concerned with how real airplanes perform or you're a flight simulator fan, this mod is for you. The level of engine simulation rivals most commercial flight simulators..
Sure. I meant to write up a wiki page, but that'll have to wait. In the mean time, here's a brief overview of the parameters
Area: area of the compressor/fan intake, in m2. Note that this doesn't include the bypass. Thrust basically scales by this. Will be set automatically if dryThrust is set.
BPR: Ratio of bypass (fan) area to core area. Zero for turbojets, generally 0.3-0.6 for low bypass turbofans, and about 3-12 for high bypass fans. When this is specified it's really a