BL Rockcrawler?

[BrianG]

Even though BL is so much more efficient and requires less maintenance, would a BL design be the best choice for rock crawling? BL motors/ESCs seem to work better at higher rpms. If you gear the vehicle down low enough to avoid cogging at very low speeds, yet get enough motor rpms to be useful, won't the motor not be loaded enough and heat up more? Would a low-kv motor like a 11-13xl be ok, or would a brushed motor be the better choice in this application despite the disadvantages?

[Sylvester]

Personally, id think bl wouldnt be the best, because even a brushed rock crawler has power, and i think that a bl motor would be less effecient and heat up, although you said you'd use a 11-13xl, i dont think you'd be using more than 10 cells in a crawler, and the lower cell count on low turn motors (such as a 13xl) will overheat due to their low rpm range, and i dont think there is gearing low enough to make it efficient enough to run on.

Than again, its all worth a try, you just need lots of $$ to experiment.

[BrianG]

That's kinda what I figured. Poop.

Experimentation is fine if you have deep pockets, which I do not. As it is, my BL Revo v2.0 is sitting in my basement waiting for more funds to complete.

BLRevo.1 is my basher, BLRevo.2 will be a racer (lighter, lower CG) utilizing more stock parts. Now I just need to learn how to control the power of BL! :027:

[MetalMan]

There was a guy that did a brushless rock crawler with an outrunner motor. Those motors spin slowly, but have huge amounts of torque. I'm drawing a blank on his name, but I remember he made a thread over at RCZ in the Brushless Forum.

[coolhandcountry]

I thought about this as well brian. I was thinking along the lines of a xl1200 or so. I am not sure how well it would accually do. I think it may be better to run brushed. I may try it out one day. I have tried a brushless with no load just very little rpm. no heat problems.

[BrianG]

Yeah, the trouble with low rpm is the cogging issue. I would think the rpms would have to be high enough to be above the cogging range, yet low enough to have tight control over the throttle.

Aside from how an outrunner is physically made (I've seen a couple at my LHS), how do they compare to "normal" BL motors? I know you said they spin slower and have more torque, but how do they heat up under different loads? Regular BL motors seem to like higher voltages and about 40k-ish rpms. To me, they are made like the all the computer fans where the coils are inside and the hub on the outside spins - except the controller in those is built on the motor PCB.

[coolhandcountry]

The cogging should only be an issue on start up. Once the rotor is found by the esc it should be good unless you stop.

There's a handful of guys on www.rccrawler.com that have tried and still run this, johnrobholmes was one of the main ones that came up with the idea and I think made it work.......been a while since I've been to that thread though, so do a search for it and it'd be sure to pop up.

[coolhandcountry]

I tried the search it wouldn't let me with out joining. I don't want to join just to search for a thread. Not today anyway.

[GriffinRU]

Go sensored brushless! Even outrunners have problems with cogging at low RPM.

Artur

[coolhandcountry]

The hv maxx may be a good crawler for it is sensored. It knows where the rotor is. It would have plenty of umph to.

http://www.rccrawler.com/forum/showt...ight=brushless
That should work......

[Jasper]

Check this out. It is a Dutch forum but there are lots off pictures!

Too much flashy stuff for me, just make sure it goes and goes fast and that's all I care about if I'm messing with BL.

[coolhandcountry]

That was a very pretty truck jasper. I couldn't read nothing about it. Thanks for the link dabid. It is very interesting on the test results.