540 kv motor v 580kv motor

[tigerman]

About to buy an electric Mustang .It has come down to Freewing 1400 Mustang or the FMS 1400 Mustang Only difference I can see is the Freewing Mustang has a 580 kv motor ,where has the FMS mustang has only a 540 kv motor Being fairly new to electric flight (Mainly an ic man just started on electric ) I still have a lot to learn How much difference will the 580kv motor have over the FMS 540 kv motor , or will they be similar in performance .I would assume the Freewing Mustang with the 580 kv motor would be the one to go for .

[Frank Skilbeck]

Not that simple, the Kv is the unloaded speed of the motor per volt, under load there will be some "slippage" so if the 540kv motor is more efficient it could turn the same size prop at a higher speed.

Unless you've got performance measurements of both motors on the same prop then it's not possible to tell which motor is better.

Plus the FMS might have a different prop than the Freewing which would compensate for the lower kv.

I wouldn't choose one or the other based on the Motor kV, but rather by the models other features.

[Biggles' Elder Brother - Moderator]

TBH I very much doubt you, or anyone else for that matter, could really detect a difference between them! The 580 will rev about 7% more, 'ish', all other things being equal, (battery, prop etc.)

I haven't had a Freewing Mustang but have heard good things about it. I have had a FMS Mustang and can confirm that is a great model. So, probably both good.

Yer pays yer money etc.

BEB

[Geoff S]

As the others have said, Kv is only one parameter for a motor and often not the overriding one. In fact in this case they are just about identical - the difference is probably within production limits. Your selection should be made based on other things.

Geoff