4 inch omni's

[hems4321]

I'm wondering if any 4 inch omni woud be able to clear the scoring platform. We ordered 4 inch dualies from andymark with the assumption that they would not get stuck. If any team has experimented with 4 inch omnis, please reply if they've worked or not.

[GeeTwo]

Originally Posted by hems4321

I'm wondering if any 4 inch omni woud be able to clear the scoring platform. We ordered 4 inch dualies from andymark with the assumption that they would not get stuck. If any team has experimented with 4 inch omnis, please reply if they've worked or not.

Not if you put four of them onto a KOP chassis and make the center wheel into a spacer - there just isn't enough ground clearance over the WCD-mounted gearbox. (We're going this this year, so I've worked this one out.)
If your chassis has enough clearance-to-length ratio at the nose to clear the 16 degree ramp on approach, and more than about 1" of clearance around the center, and you haven't geared too high or used slick omni wheels, you should be able to manage it.

[sdcantrell56]

Do a quick sketch in cad. Its possible but not trivial.

[Chief Hedgehog]

Yesterday we had Greenhorn ' s robot at our business expo and it had little to no problem getting over the scoring problem. It has 4" omnis and a 6" AM omni on the slide.

[Dunngeon]

Originally Posted by GeeTwo

Not if you put four of them onto a KOP chassis and make the center wheel into a spacer - there just isn't enough ground clearance over the WCD-mounted gearbox. (We're going this this year, so I've worked this one out.)
If your chassis has enough clearance-to-length ratio at the nose to clear the 16 degree ramp on approach, and more than about 1" of clearance around the center, and you haven't geared too high or used slick omni wheels, you should be able to manage it.

We tested this with a custom chassis from last year, definitely agree with GeeTwo; gearbox height is the biggest issue.

In the future, it would be good to test the design in CAD or on a piece of paper before you buy. That could have been an expensive mistake.

[nixiebunny]

We put VexPro 4" omnis on our drive base, which has the wheels mounted at 45 degrees in each corner, in gearboxes that are mounted 1" below the chassis. It clears the platform just fine.

[Taylor]

Depends on the drive train setup. We've put a pair of 4" duraomnis on the front of our 6WD and have had no problems whatsoever. I was personally surprised at how well they've worked; I was expecting them to slide sideways on the slick ramp. However, we've found that the grippy kit wheels in the middle and back keep the robot steady.
Our chassis is just under 28" long.
However, I would not expect the same results with a 42" long 4WD system.