Electric motors

[amtpdb1]

Hi:
I have been flying rc for many years. I have just started flying electrics and enjoy watching Bruces XJET.
I have been looking and cannot find a explanation for the numbers on the motors. I have found that in some cases the first 2 numbers tell you the size of the motor. What I have not found is why you can have a number of motors that have the same size but have either a different rpm per volt or motor wraps. Some have 6 wraps of one type of wire, 8 wraps of wire, 6 wraps of 2 or 3 strands of a certain gauge of wire instead of one strand and so on. Is there some place, or has Bruce done a video, where some on could tell you what happens with different combinations, or how the wraps match to the rpm's to to thrust, and so on?
If there isn't something out there, maybe Bruce might be talked into doing a video to explain this and more on the different motors,sizes,thrust and how they relate to wire size and wraps and so on.
Thanks in advance for any responses.

[Treebuster]

Not sure if this will help but free download for 30 days.....

http://www.motocalc.com/viewman.htm

[amtpdb1]

Thanks for the web site. I will check it out. Some places will make motors to order and I was wondering about the results of asking for different rpm's or different wraps of wire or number of wraps on the motor.
Thanks again.