Team 254 Presents: 2017 Misfire Technical Binder and Build Blogs

In your fuel intake design, I see two pistons on each side. I don’t exactly understand their use and placement. Can you explain?

The purpose of the two pneumatic cylinders is to deploy the fuel intake at the start of each match. Their placement is such that when the intake is stowed within the frame perimeter, they push it and it swings down over the bumper. In our initial design, these cylinders also expanded our hopper when the intake swung down. However, this proved to be somewhat inconsistent, and we have since changed the hopper deployment to be triggered by two independent cylinders that push the hopper walls outwards on each side.

Will there be a CAD release for those of us who are more visual learners than auditory learners?

We do not release our CAD. However if you do have any questions, we will be happy to answer them.

Have you, or will you post the autonomous path planning web app and implementation?

How do you mount the pulleys onto 775pros? It doesn’t look like you use WCP’s 775 pulleys, and we have had difficulty finding different pulleys easily mounted to the 775.

Try SDP-SI

I’m not a member of Team 254, but I believe the web app you are looking for is in the “cheesy_path” folder of their 2017 code located here.

We use the GT2 3mm 12 Tooth 775 Pro Pinions which we press onto the motor shaft. We leave around a 1/8" clearance between the pinion and the motor

Just out of curiosity, is there a particular reason as to why?

What pinion pulleys did you guys use for your 775s on your shooter? They do not look like the ones from west coast products.

I really like how you guys used polycarb with slots that was bent into a curve for your shooter.

In addition the one way bearing is genius, and one of those things that I thought to myself “why did I not think of that”.

Paulius Pace

2 posts up.

You guys stated that you went with a shifting gearbox for a low gear to push people, but then only went with 2 cims instead of 3. Why would you make that a focus but then not make it work even better with 3 cims?

Adding CIM’s doesn’t give you more pushing power, it allows you to increase your speed in low gear and maintain the same pushing power. Your pushing power is a function of weight and coefficient of friction. As long as you can spin your wheels in low gear (everyone should be designing for this), it’s totally independent of speed.

Someone help me out here as I can’t seem to find the thread/whitepaper I was reading, but I believe adding the extra 2 cims in this case doesn’t really change overall pushing power. It does however help with acceleration. Something to do with current draw and traction.

Edit: Cory beat me to it.

For the shooter wheel. We looked into the same type of wheels, but unsure of the best way mount it.
Did you make hex hubs? Or just broach them?

They made clamping collar type hubs that clamped to their tube axle. I remember Cory or someone else commenting on it a while ago but I can’t seem to find it.

When we redesigned the shooter to have two wheels per ball path we changed to a larger OD tube and simply pressed on/loctited the wheels on to the shaft. We modified the plugs to be slightly longer such that we would press two wheels on each side of the tube flush to the end of the tube and then install the plugs which would space it appropriately away from the side plates to center the two wheels in the channels.

In hindsight the fancy custom clamping hubs were unnecessary.

.018" is exactly what he recommends for any length run of 25 chain.
.013" is what he recommends for 35 chain.

Here is the presentation he made for us at the Michigan State Champs a while back:

You’ll want time index 22:23.

I noticed your wheel drop was 0.06" this year. Was that just because of the relatively short wheelbase, were you willing to accept more scrubbing in exchange for reduced rock for shooting stability, are colsons better suited to less drop, or was there another reason?

I did a quick search for Barrage’s center drop and didn’t find anything so maybe it’s not a new change, but I had thought previously that ~0.125" was the standard drop for 254 robots.