New AndyMark Product Game Hint???

[Lireal]

Originally Posted by Billfred

What is on the paper that says product teaser?

[WSiggs]

Originally Posted by Lireal

What is on the paper that says product teaser?

A product teaser.

In all seriousness though it looks kindof like someone took apart a motor and spread it out.

[Billfred]

Originally Posted by AdamHeard

That number seems DANGEROUSLY high to tell general case to team's at large.

With compression and a high number of shots, I'd be very concerned running at that number.

We tested them pretty thoroughly with old FTC balls, including a 1" practice golf ball that has basically zero squish of its own, and the engineers derated it to a number they were confident in. Obviously, anyone running any crazy-high-speed system should inspect those wheels early and often.

Nathan did the actual testing, and he may be able to provide more detail.

Originally Posted by Lireal

What is on the paper that says product teaser?

A product that we want to tease.

[bdaroz]

Originally Posted by Billfred

A product that we want to tease.

And on the back of the paper is the 2018 water game field element CAD drawing.... come on, we know...

[AdamHeard]

Originally Posted by Billfred

We tested them pretty thoroughly with old FTC balls, including a 1" practice golf ball that has basically zero squish of its own, and the engineers derated it to a number they were confident in. Obviously, anyone running any crazy-high-speed system should inspect those wheels early and often.

Nathan did the actual testing, and he may be able to provide more detail.



A product that we want to tease.

As of right now the site still shows 9001 RPM.

What is pretty thoroughly? 1000 shots? 10000?

I know some of the teams running the fairlane teardrop wheels in 2013 replaced them a few times over the season due to tears propagating.

[Lil' Lavery]

My only comment with the "9001" rating is that carrying things to that amount of significant figures implies strong confidence in that specific number. While I certainly get the "over 9000" meme, many FIRST mentors (especially those over the age of 35 or so) aren't going to, and may interpret that 9001 figure to be a more scientifically approached limit given the specificity to 4 sig figs.

[snoman]

Has any one tried 3d printing there own wheel of this type? I have a spool of a flexible material I have been wanting to try out.
https://ninjatek.com/products/filaments/ninjaflex/

[RoboChair]

Originally Posted by Lil' Lavery

My only comment with the "9001" rating is that carrying things to that amount of significant figures implies strong confidence in that specific number. While I certainly get the "over 9000" meme, many FIRST mentors (especially those over the age of 35 or so) aren't going to, and may interpret that 9001 figure to be a more scientifically approached limit given the specificity to 4 sig figs.

You are assuming that the zeroes are not significant figures already. Zeros can be significant.

Tell a machinist to make a part with a dimension of 1.00000" and see how hard they hit you. Whereas 1.00" and they won't bat an eye.

[Lil' Lavery]

Originally Posted by RoboChair

You are assuming that the zeroes are not significant figures already. Zeros can be significant.

Tell a machinist to make a part with a dimension of 1.00000" and see how hard they hit you. Whereas 1.00" and they won't bat an eye.

Oh, I agree. But these aren't zeroes beyond the decimal point. The zeroes in "9000" could be significant, or they could be placeholders for the proper unit value. However, the zeroes in "9001" are definitely significant.

[Richard Wallace]

My simple minded calculation of stress on the 4" wheel in question:

The wheel's outer section ("rim") is about 5 mm thick, 25 mm wide, and 320 mm long. Its volume is about 40 cc. Assume its density is about 1.5 g/cc so its mass is about 60 gram or 0.13 lb.

At 9000 rev/min, the "rim" has ~4400g centripetal acceleration, or ~570 lb. centripetal load. This stress acts on the spokes and is divided equally among them, at least until the wheel loses symmetry by deforming. So each spoke takes one-eleventh of the centripetal load, or 52 lb. That spoke stress is born by the same cross-section as the rim, or about 0.2 square inch, so the material must withstand ~ 260 PSI.

Neoprene yields somewhere above 500 PSI. How much higher? Probably depends on the durometer.

Please, will a real mechanical engineer check this for me? I know it ignores stress-rise in corners, for example. Those will be more significant for the AM design than for the tear-drop spoke flex-grip rollers we've bought from McMaster-Carr.

[PAR_WIG1350]

Originally Posted by Lireal

What is on the paper that says product teaser?

It looks like this, but it doesn't seem to have been altered from its current version.