West Coast Drive, WCD

[ajlapp]

Here's an early shot of FRC27, Team RUSH, using our Super Light Chassis kit.

FRC 27 on Super Light Chassis

You can clearly see the cantilevered wheels and the bumper standoffs.

[pwnageNick]

I think everyone has said it right. ALthough two things, the middle wheel doesn't have to be directly driven, and there can be framing on the outside if desired. Our team uses belts and is not directly driving the middle wheel, and we have a sheet metal plate on the inside and outside of the wheel. This is still west coast I believe right? Unless our drive train isn't considered west coast...

[thefro526]

Originally Posted by pwnageNick

I think everyone has said it right. ALthough two things, the middle wheel doesn't have to be directly driven, and there can be framing on the outside if desired. Our team uses belts and is not directly driving the middle wheel, and we have a sheet metal plate on the inside and outside of the wheel. This is still west coast I believe right? Unless our drive train isn't considered west coast...

For it to be a "True" West Coast Drive, one of the wheels should be direct driven, and the wheels should be cantilevered.

If your drive isn't cantilevered - if it has supports on the outside basically - then it's probably not a WCD. (Unless the support is superficial or for bumper mounting)

[Chris is me]

Not every single six wheel drop center drivetrain is "West Coast".

However, not every non - "West Coast" drive is bad, by any means. If I used sheetmetal instead of welded tube to build robots, I probably wouldn't cantilever the wheels, because it doesn't really save much material weight.

[R.C.]

As others have stated, West Coast Drive System was created by Glen on Team 60 and has been popularized by FRC 254/968/973/1538 etc...

But the best pics of the system:

http://team254.com/media/photos/2010-frc-build-season

254 does a great job showcasing the WCD.

-RC

[pwnageNick]

Maybe that's why my mentor had me write "Midwest Drive" on our post this year http://www.chiefdelphi.com/forums/sh...ghlight=pwnage

And we made the decision to have sheetmetal plates on the inside and outside for strength, because last year our wheels got bent, and then we made plates for IRI last year with great results. http://pwnage.foxvalleyrobotics.com/..._newrobot.html

[thefro526]

Nick, from what I can see, that looks like a standard drive train to me.

[sdcantrell56]

Originally Posted by ajlapp

Here's an early shot of FRC27, Team RUSH, using our Super Light Chassis kit.

FRC 27 on Super Light Chassis

You can clearly see the cantilevered wheels and the bumper standoffs.

That's a great looking and clean chassis! Only thing I don't totally understand is why you go dead axle instead of live with the chain on the opposite side? Not really a critique just wondering what the decision making process was.

[HarveyAce]

Hello All!
After following this thread, I was curious about what the advadntages of WCD are, and when is the optimal situations to employ such a system. I am curious because we are about to begin working on offseason training which might entail building various drive chassis and systems to get some offseason design experience. Thanks!

[sdcantrell56]

The advantages that lead us to a west coast-ish style drive were:
1) ease of maintenance
2) wider track width
3) less weight
4) protected belts

We were already planning on direct driving a wheel no matter what frame style we chose and also leaning heavily towards a live axle system since for us it is easier to fabricate the components so a west coast inspired drive fit in perfectly with what we were already leaning towards.

[ajlapp]

That's a great looking and clean chassis! Only thing I don't totally understand is why you go dead axle instead of live with the chain on the opposite side? Not really a critique just wondering what the decision making process was.

Some of the reasons:

-standard axles. we use chromoly tube to form the dead axles.....simply cut to length. this reduces machining.
-we use AM standard wheels. the plaction variety is cheaper than the performance wheel....so using a dead axle saves us having to add AM hex or key hubs back into the wheel, thus increasing the cost.
-we can service the wheels just as easy as any live axle setup i've seen. when the chain is tensioned properly it slides off the axle with the wheel as part of the assembly...no issues.
-dead axle blocks are slightly easier to manufacture....just ream an undersized hole for the axle. no precise bearing fit.
-chain on the outside of the frame rail doesn't interfere with any assembly on the inside....this makes life easier when we have to add something unplanned inside the perimeter
-we can adjust the rocker by swapping out different end blocks. live axle blocks don't allow this because there isn't enough material to machine away in the vertical direction.
-we used to use custom Dewalt planetary drive transmission....they wouldn't have worked well with a double sprocket on the inside of the chassis rail.

Note that the Super Light Chassis product can be used in either variety. The standard version is "dead" axle, but "live" axle blocks can be dropped into the outer wheel positions.

[Arefin Bari]

Originally Posted by HarveyAce

Hello All!
After following this thread, I was curious about what the advadntages of WCD are, and when is the optimal situations to employ such a system. I am curious because we are about to begin working on offseason training which might entail building various drive chassis and systems to get some offseason design experience. Thanks!

The one neat thing I loved about our chassis this past season was how easy it was to take the wheels off. Given the fact that we never broke a wheel this season; but after last season and going through three plaction wheels, this one feature definitely caught my eye.