Toughbox vs KOP Toughbox Mini

[nathan_hui]

I see. I guess you'd only see the current problem in a pushing match, or when you start flooring the accelerator. But for the purposes of the OP, extra motors (to the limit of the Toughboxes) shouldn't make a difference.

[Ether]

Originally Posted by nathan_hui

extra motors (to the limit of the Toughboxes) shouldn't make a difference.

Extra motors on a drivetrain make a difference when it comes to not popping breakers:

http://www.chiefdelphi.com/forums/sh...48&postcount=8

[Xenozero]

Originally Posted by nathan_hui

Probably, since the big toughboxes were originally paired with the old KoP chassis (which is now illegal, I believe). But what do I know? I suspect you could, but do the math (you need to make sure that the output shaft of the toughbox doesn't interfere with the wheels, and that's pretty much it.)

hey, i would like to know where you found out that the old kop chassis is illegal, would you mind showing me where it says it? my team was thinking about using an old channel that we had lying around the shop.

[FrankJ]

There is a section in the rules about reusing KOP from previous years. For the channels you basically have to account for the cost in the bill of materials.

It also has not to have been "modified" before kickoff. It is up to your GP to decide just what that means.

[Chris is me]

I think the KoP drive speed is very good this year and I don't see much of a reason to go more slowly, especially with the KoP drive using relatively precise belts. It's a good balance of speed and "pushing power".

[JamesCH95]

Originally Posted by nathan_hui

Increasing the gear ratio (making the drive slower) would make it harder for someone else to push you around, but you run the risk of popping breakers.

Again, what Christopher said, though I think the PG71 was also restricted last year.

Taking a little time to read and understand this chart, and even doing some of the basic math for myself, I learned a lot about drivetrains and their limiting factors.

[nathan_hui]

The old KoP chassis will not fit the frame perimter rules. COTS materials from the KoP chassis are still legal, just not the entire kit.

And Ether, thank you for clearing up my confusion. I believe I understand the relationship between motors, torque, and current a lot better now.

[Ether]

Originally Posted by nathan_hui

And Ether, thank you for clearing up my confusion. I believe I understand the relationship between motors, torque, and current a lot better now.

You are most welcome.

If you haven't seen it yet, here's a little motor calculator I wrote a while back that may give you further insight.

[Chris is me]

The chart James posted is a GREAT introduction to drive design, and I recommend everyone read it. That said, if you don't plan on continuous pushing, you can safely bring a single speed into the 10-13 feet per second range without too many problems. Just remember the faster you gear, the less versatile you are in terms of pushing.

[Donut]

Originally Posted by Chris is me

That said, if you don't plan on continuous pushing, you can safely bring a single speed into the 10-13 feet per second range without too many problems. Just remember the faster you gear, the less versatile you are in terms of pushing.

I'll second this with some anecdotal experience. Back in 2008 (Overdrive) we geared a 4 CIM single speed drivetrain for 13.5 fps. We did not pop a breaker once throughout competition but you will notice that at high speeds like this your motors run quite a bit hotter.

Nothing substitutes doing the math if you're uncertain or want to try something unconventional. In 2009 we ran our drivetrain on 2 Banebots RS550 motors because the math worked out.