pic: MVRT Off-Season Sheet-metal Chassis

CAD model of MVRT’s Sheetmetal Chassis. Uses 4" VEX DT wheels driven by 35mm chain and 2 VEX 2 CIM Ball Shifters.

High Speed: 15.86 ft/s
Low Speed: 7 ft/s

Looking to mount electronics along the C channel wall of the sheet-metal(along the back). Anyone have any experience with this?

Need to add bumper mounts and chain tensioners. Looking to use McMaster’s snap slide latches in addition to L-channel for bumper mounts and McMaster spring chain tensioners. Anyone have any suggestions in this area?

Let me just start by saying this is a great looking chassis.

To answer some of your questions:
Mounting electronics on the walls isn’t a bad idea, but it can become very cluttered very quickly. I think I designed a chassis that had back wall mounted electronics but we never ended up cutting it.

Bumper mounts really depend on what you want to do. I have seen many different methods. Some teams do a bolt through a lightening hole, others will use angle iron to create a lip for the bumper to sit on.

We have been working on tensioning methods this last season. The best way we have found so far is to use fixed position tensioners on an array or line of holes. Slots and offcenter tensioners tend to slide out of place after frequent use, but the only thing that will ruin the tensions on a fixed position tensioner is the chain stretching. Whenever that happens we just move the tensioner down one peg and keep on driving. We have been fighting this problem for years and the method that requires the least maintaiance and headache is fixed postion tensioners with an array of holes.
We used them here if you want an example. The white plastic is delrin.

We toyed with something similar last year with a kit chassis. We found that not only is there too little space for very much, anything mounted in there will be hard to reach and hard to see for diagnostic purposes. We wound up moving the electronics elsewhere and put an air tank back in that volume.

CAD? please pls? :slight_smile:

What’s the weight on that thing? Looks really beefy.

Around 23 pounds.

Does that include CIMs and gearboxes?

Anand, theyes are getting good without you. :stuck_out_tongue:

I’m a big fan of these automotive panel nuts for sheet metal chasses. Just add 1/4-20 bolts and a cordless impact driver, and you have a super strong bumper connection that comes off in seconds.

Looks like they imported the STEP of the ballshifters and didn’t change them, so it’s likely they didn’t even add mass properties, hence why Anand is asking about their weight inclusion.


Thanks for the suggestions, I really appreciate it!

A few tips:

-Close the box sections for the frame, it’ll make them significantly stronger.
-Add in a bellypan, it’ll help with torsional stiffness
-The split front part isn’t very rigid either - extra support there (+bellypan) can help with that.

Check out some of 971’s drivetrains for some good methods of sheet metal implementation. There are some helpful rectangular and octagonal drivetrains in the 2015 section that you should definitely check out.

Update: CAD Files