pic: Jimmy Talon

my god inserts dank meme

You guys took breaking the defenses a bit too literally… :smiley:

On a more serious note, what was the reason for going with ten wheel as opposed to eight wheel? Or even six wheel?


Look forward to seeing you at Suffield (and WPI)

There are a number of factors that combined toward our decision. The primary goal was to be able to destroy both defenses in at least four categories, risk free. Thus the drive train gained even more value then the already high value we normally place on drive train design. We established a rough chassis perimeter based on the diameter of the ball and the:

-Packaging of our selected shooter through prototyping
-Packaging of our climbing concept
-Packaging our drive train components

Based on the stability and handling performance of 8WD, our original goal was an 8WD. Which left us with two options from our investigating perspective. 6" or 8" wheels. Clearly, an 8" wheel long 8WD with the 120" perimeter rule gives you the optimum defensive terrain crossing ability. However, when designing to go under the low bar safely and maintain our shooter design it was evident every precious inch counted. Through prototyping we determined a 8WD 6" wheel would do the job effectively. As part of prototyping we created a sketch with all the terrain based defenses and our chassis with a spread center 8WD. It was clear that no configuration of wheel spacing with our chassis length would allow us to drive over the moat without high-pointing on our WCD chassis rail. We went back to our prototype and added a 5" free-wheeling wheel in the middle of wheel set. It became evident that this concept would do more hurt than harm and thus we powered it giving us far better results than a standard 8WD, specifically a much smoother transition over the terrain defenses and not requiring us to “dukes-the-hazard” the defenses which we wanted to avoid when we calculated the theoretical loads induced into our shafts and bearings at a average ramming speed of 10 ft/s. We went back to our sketch and incorporated 10 6" wheels and observed that fact that at no point would there be more than a 1.25" gap at the point where the belly pan intersected with our wheels thus eliminating a highpoint from the 1.5" wide mote rails and the uneven terrain. So given our goals and the results of our prototyping, the decision was easy.

Nice description of your iterative design process. I’ve added you to my “teams to watch” to see how the 10 wheels work out. You might become the “North Coast Drive” team.

Any chance for a description how you drive all those wheels? Let me push my luck and ask for a picture too.

Good luck!!

See the posted image.


edited to add: Thanks James, we cross posted. Thanks for posting the link, that’s what I was looking for.