Re: Ball dimensional variability
 

The bladders are actually supposed to be 25 inches in diameter. That could explain why they tend to be on the large side. http://www.sportogo.com/2565cmbladder.aspx

Re: Ball dimensional variability
 

gotta think that inflation pressure is going to have some effect here, too.

how uniform will *that* be at comps?

Re: Ball dimensional variability
 

At comp, they might do the same as what they did in 2011 and have an inflation box that they use that is roughly the volume the ball is supposed to be.

Re: Ball dimensional variability
 

psst...
http://www.youtube.com/watch?v=Azc8AKzgEwE

Re: Ball dimensional variability
 

If you noticed during 2011 some (many?) field workers just pumped up the tubes as hard as they could, shoved the sizing gauge over the tube and went "hey, it fits!" and put them out on the field grossly over-sized. In 2007 the exact opposite was true, tubes were generally grossly under-inflated.

No matter what the regulation is we better count on someone who does not appreciate the implications of their seemingly trivial volunteer job at an event. Balls could be very over-inflated, under-inflated, or both. Plan accordingly.

Re: Ball dimensional variability
 

We called Sportogo and confirmed that this is the piece used in the official FIRST balls. Because we already popped ours and needed a replacement!

Re: Ball dimensional variability
 

We followed this inflation guide:
http://www.usfirst.org/sites/default...ance_Guide.pdf

We measured the circumference. Independent measurements were made by three students. The average diameter of eight measurements was 24.7 inches.

We got burned by larger tournament tubes than we had designed and practiced with in 2011 so we'll make sure that we take ball diameter variance into account this year.

Re: Ball dimensional variability
 

That guide is junk, it essentially is a spec based on feelings and opinion and not numbers.

Re: Ball dimensional variability
 

Essentially, "Inflate the balls until they are properly inflated."

Re: Ball dimensional variability
 

It's not quite as tautological as you make it sound. Using the zipper as a tightness gauge makes the subjective interpretation of "properly inflated" a narrower range of possibilities than it might otherwise be.

Re: Ball dimensional variability
 

I thought it was fine. It says to design for several inches of variability.

Re: Ball dimensional variability
 

I would assume that ball size variability would affect ball intake designs the most.
Take it out of the equation.:)

Re: Ball dimensional variability
 

Did I just see your username correctly? DaisyPoof? Team 254? haha...

Re: Ball dimensional variability
 

DaisyPoof sounds like what EJ would name the robot if the rest of the team would let him.

Re: Ball dimensional variability
 

Who started the Decepticon thing then?