Drive motor options

[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.

[Eventorizon]

This Australian build thread shows a machine with brushless drive, but there isn't much detail: http://robowars.org/forum/viewtopic....=asc&start=615

He recently put this info up (Directly and indirectly)...

ESCs: Trackstar 80A brushless car controlers

Motors: NTM Prop Drive 42-38 750Kv (Picture matched and found here: http://www.hobbyking.com/hobbyking/s...arehouse_.html)

Reduction: 10:1

Wheel Dia: 102mm (Taken from ebay. Same width, hex and scale so I am assuming the OD matches too. http://www.ebay.com/itm/4PCS-17mm-Hu...-/360669106232

Provided the ESC's work off the shelf, this should be easy enough to reproduce and modify. I have to say that guy has some serious skills. Check the 43rd page, all those designs!

Or here: http://i34.photobucket.com/albums/d1...psba4b0087.jpg

[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.

[plargen]

This Australian build thread shows a machine with brushless drive, but there isn't much detail: http://robowars.org/forum/viewtopic....=asc&start=615

if you look further back he also made this

[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