Craighead

I need a motor that can directly drive, at the hub a 6" diameter wheel that weighs a good 1/3 of a pound. It's a very thin, wagon-like wheel so it's more about the weight than the friction.

The motor must run at 7.2v or below and the smallest size possible. Oh, and it has to be brushed

This is a custom project and I have no room to mount any sort of gearbox and it's going to driven like a tank with two seperate drive wheels. Trying to stay away from the expense of two ESC for brushless motors.

I tried the Losi Mini Crawler motors but they are no match.

Am I asking too much? Anything out there with gobs of torque that can move my wago this way?

Thanks!

HJJFFFAA

You want an outrunner.

Craighead

Like this?

http://www.rcuniverse.com/magazine/n...roduct_id=3378

Do I have to use that ESC?

I'm basically gutting one of those HengLong tanks and using the radio, receiver and ESC out of that because it has a "tank specific" style of controller.(both sticks just move forward and back with spring resistance)

Thanks for the quick reply.

HJJFFFAA

Yep, just like that. It's brushless so you'll need a brushless ESC.

Craighead

Ah I missed that somehow.

Are there any brushed alternatives?

Craighead

I'm looking at these Outrunners on Ebay and there are a lot of varying "KV" ratings. Is this a measurment of torque output? Higher or lower the better?

Please excuse my ignorance. I've been out of the R/C scene since my Tamiya Frog.

HJJFFFAA

There are no brushed outrunners I know of. For kv you'll want to get as low as you can.

Candre23

My Feedback: (8)

When you say "directly drive", do you mean the wheel will somehow be mounted on the output shaft itself? Because I don't think that's an option for any motor. The bearings can't handle that kind of stress. If you mean that the motor will have a pinion which will turn a spur directly mounted to the axle (like on some touring cars), then you should be fine with a crawler motor. The slowest brushed motors are made for crawlers - I think they max out at about 55t. You should have enough gearing options to make it work. You can find them pretty cheap, as long as you don't expect stellar performance: http://www3.towerhobbies.com/cgi-bin...?&I=LXYNJ7&P=7

HJJFFFAA

People mount wheels directly to outrunners all the time. They handle it great.

TheyDontWantMusic

I really don't think it would.

for a short time, yes, and on road, they should be ok, but it depends entirely on where its being used.

HJJFFFAA

Why? What stresses are these bearing gonna see that normsal wheel bearings won't? In fact, these bearings are BETTER supported than wheel bearings. It can and has been done.

Craighead

Yes, it will be directly driven off the motor shaft.

Speaking of which....

Where can I find motor shaft extensions? Like an extended shaft with a set screw in it?

Thanks

HJJFFFAA

I don't know if something like this would suit you.

http://www.findingking.com/p-29233-m....aspx?ref=base

Craighead

Yes something like that but isn't the IDa little large for an electric motor?

Also, yes this will only be used "on road" or carpet.

HJJFFFAA

It is, I was just giving an example. I can't shop around for you. Just Google "motor shaft extensions" and look for one with the correct dimensions.

Craighead

Thanks.

Yeah I have googled around but I haven't really found anything suitable.

I thought it would be a more common item.