View Full Version : Help decoding electric motors

11-24-2005, 09:12 PM
Ok, I think maybe after reading allot I might understand some. The kv of a motor is the rpm it will turn with each volt applied. If this is correct using a 3s lipo would require a lower kv rating over a 2s. Also a lower kv rating with a 3s lipo would need a smaller prop. A higher kv rating would spin a larger prop but needs to be paired with a smaller voltage battery. I hope this is correct. Knowing the kv rating of a motor how do you get to the part of knowing if it would fly an airplane of a certain weight? Or do you need more info like the amp rating? Please verify my understanding or straighten me out.:o

11-24-2005, 10:07 PM
The general rule is the LOWER the Kv the LARGER the prop you can spin (large props turn slower and still give more thrust/power). I'm not sure how you get it the other way round.

You need a lot more than just the Kv to tell you what a motor will do. The physical size, maximum current and power rating are interesting too. It gets quite complicated which is why most people use programs like Motocalc to get an idea of how things work with the many different variables.