+c0re-

I'm very new to brushless setups, so please excuse the simple question.

There are two motors I'm looking at, both identically priced, both seem to have the same specifications in terms of efficiency, power source etc. One is 950rpm/v, and the other is 1220 rpm/v.

Common sense tells me that the faster motor would be better, but there has to be a drawback to using a faster motor? Will the faster one have less torque? Guessing it will drain the battery faster?

The two motors I'm looking at are:

http://cgi.ebay.co.uk/Brushless-Plan...QQcmdZViewItem

http://cgi.ebay.co.uk/Brushless-Plan...QQcmdZViewItem

And this is to go in a cap 32, with li-poly battery.

Thanks for any help or info on the difference between these two.

Matt Kirsch

My Feedback: (21)

The difference is in how fast each motor turns on a given voltage. That's what the Kv rating indicates, RPMs per Volt.

The motor with the higher Kv rating spins a smaller prop faster, so it would be more appropriate on a general sport plane. The motor with the lower Kv rating spins a larger prop slower, so it's more appropriate on a 3D plane.

Whether the motor is appropriate or not depends on what a "CAP 32" is, what its power requirements are, and how you plan to get that power.

wvl

if you want full 3D, including hovering, choose the slower motor. It will turn larger props and have lots of torque, the plane will be slow as a 3D plane should be. If you want speed, choose the other engine, it will swing smaller props for speed, not for torque. Hovering will be more difficult.

A CAP is a 3D plane, so the slow engine is the best option to my opinion.

Matt Kirsch

My Feedback: (21)

I guess I wasn't really that clear... Before we choose the motor, we need to figure out what kind of plane it is, and how heavy it will be ready-to-fly, so we can figure out how much power it needs. Once we know that, we can see if the motor will handle that much power. It makes no sense to use a motor that can only handle 150 Watts if the plane needs 300 Watts to fly 3D... The motor will burn up.

+c0re-,

Could you post some details on the plane? With that information, it's fairly easy to figure out if one of these motors is appropriate, or if you're barking up the wrong tree entirely...

+c0re-

Thanks for the replies guys, sorry - made a typo in the first post. It's a Cap 232, it's not built by any manufacturer I've heard of before, but here's the link to it on ebay. http://cgi.ebay.com/ws/eBayISAPI.dll...&category=2563

Basic specs on it are:

4ch, micro servos
36.6" wingspan
22.5 sq. in wing area
.57 lbs (260 grams) flying weight,
brushless 380/450 motor reccomended.

I'm more interested in good flight performance with a few stunts, moreso rather than purely 3d stuff. I realise this is a 3d/aerobatic plane, so from what you've all said it sounds like the faster motor may be my best bet if I value speed slightly over 3d ability?

Any more opinions or advice would be great, thanks ever so much for the help

Matt Kirsch

My Feedback: (21)

I'd still go with the lower Kv motor. It'll be plenty fast with that. Prop it for about 10 Amps on a 3S LiPoly (about a 9x4.7), and it'll be ballistic.