Drive motor options

[Max]

The other thing I thought of was using the newish brushless dewalt cordless drills- I imagine this could provide a good brushless motor with the appropriate gearing already made up so it can give the same speed output as a normal drill.
I dare say these new drills are expensive and parts will probably have to be machined to hold the motor and gearbox together but I guess it's an option if you can find a speed controller.

[Liftoff]

I take it those are custom built boxes Mario, right? They look well suited for my use if they can fit inside a 54mm dia 40mm wide wheel.

Better stick to brushed motors then, rather than getting into problems controlling a brushless setup. That said I think I've seen a local team using a brushless setup on their robot...not sure tho as I only saw a photo of the underside and what looked like two brushless motors. Will try to find the photo and post it here, maybe someone can identify the components.

[maddox10]

Those are both custom sets. The Skyfall set is using ring gears from a wheelchair.
Firestarter uses homemade 7075 T6 ali ring gears. Kos (Builder of TAN) started those by building an add on tool for my small mill.

To fit in a 54mm diameter wheel.... with thin walled bronze bushings and a very thin rubber layer (is that needed for you?) I guess I can fit a 36mm diameter motor in such a setup. But the motor and gears will stick out on both sides of the wheel, as I don't know any brushed motor 36mm diameter that is shorter than 40mm.

[Liftoff]

What's the lowest ratio you can get from them Mario?

[maddox10]

As low as needed, but each stage adds weight, complexity and size.

It also depends on what gear-ring you have available.

[leorcc]

We are testing with brushless drive as well but in a lower weightclass. Still there is no reason to assume the drive will be any different with the larger ones than the results we've had with the smaller ones. One thing about the Trackstar ESC's, the programming card is quite useful but one of the settings is not available on that card. You would need to use the transmitter programming option for that.

[Ellis]

States on the thread that the wheels are 100mm. Believe that ESC is rated for just 3s, so at 10:1, that's 10mph top speed. Over 1hp potential drive power. Pretty nice, and as per the video, drives quite nicely. Doesn't quite look like 10mph, though. Might be running 2s.

Either way, it proves the point that it's viable. Just for high power drives, the speedos are behind a bit.

That said, I believe the American machine "Hot Stuff" (a 60lber) uses brushless drive, too. Very powerful. No idea on actual specs, but it's running some Turnigy Trackstar motors into Dewalt gearboxes, and cheapo Chinese motor controllers. Might be worth trying to find out more. There are several videos on the builder's channel of tests: http://www.youtube.com/user/dtrobotics/videos

[Liftoff]

Does it make any difference if you use an unsensored motor on a sensored esc?

[Ellis]

You have to match them. Sensored motor needs a sensored speedo, and vice-versa.

[Liftoff]

Wouldn't this esc be better suited to those brushless motors? Its unsensored, like the motors are, and it can take up to 6s lipo if I understood correctly....reading through the feedfack on this esc one guy mentioned that it can also control a brushed motor... don't know if it's possible at all.
http://hobbyking.com/hobbyking/store...s_Car_ESC.html

I'm really tempted