Chris - I was the same when I started with EP ... motor manufacturers do not use a standard for their motors ... like OS91/Magnum91/G90 etc. KV means how many RPM a motor will turn for every 1V. The higher the KV means the hotter the motor. A hotter motor is generally good for fast planes where you wanna throw a smaller prop (if you used a large one it will be torturing the motor and will be pulling a lot of AMPS, your ESC/batt/motor may be damaged). Its got a lot to do with experimenting, I am not one to use MotorCalc, I read a lot from forums and see what sort of numbers people are getting and then I will go for it. The choice of prop also affects how much current will be drawn and how your plane will perform.

Watts is the amount of power the motor has, its calculated by multiplying the voltage with the amps drawn. Hence, on 11v with 22A you have 232Watts. This you can get from the manufacturers chart of by testing. For great 3D a lot of people want up to about 150W per pound.

When some manufacturers say for planes us to 100 oz they mean things like gliders/sail planes. My usual way of looking at it is to see how many RPM for a certain prop. E.g. a certain 3D plane of say 24 oz will have great performance if the motor can turn an APC 11x4.5 @ 7,750 RPM.

I hear the KM is not 13 oz! It probably is when EMPTY!