Game piece inflation

[jman4747]

We really should not have a problem putting a ball in a box and pumping it up till it touches the sides.

I don't see why you can't just pump them up in the morning and check them at lunch each day and be done. Or even just once a day (I'm assuming they may lose some air getting hit and squished all day).

The rules say approximately 2ft diameter. Excuse me for designing for 23"-25".

[Annatreptic]

They were extremely inflated at teh Glacier Peak PNW regional as well. So inflated in fact, that it started to continuously stall our motor and wouldn't allow us to gather the balls at all. We want to put some slop in our pneumatic mounts to our arm to try to fix this problem, any other teams done things to help this problem?

[Brandon Holley]

Originally Posted by Patrick Flynn

Does anyone else think that a sizing box is not the way to go here? We have no idea the tolerances that these balls are designed at. If the balls are +/- .5in a sizing box would lead to over and under inflated balls, and then everyone would be complaining about that.

I think there is a bunch of confusion here.
Having all balls the same size in diameter would lead to different levels of inflation.
Having all balls inflated to the same PSI would lead to different sizes, in diameter.

Simply put the tolerances on there balls are not +/-.0000000001 There is no way to have all these balls be the same size and same pressure.

Has this actually been tried out tho? Its all speculation until you see the actual results.

I don't think anyone is asking for 10 decimal places of tolerance on the diameter.... However a single decimal place or 2 would certainly be welcome.

Honestly I would take one or the other if it helps consistency in an event and event to event. Right now, we don't have either besides a general 'look' and 'feel'.

-Brando

[tr6scott]

Remember this video was to address this concern. http://youtu.be/Azc8AKzgEwE

The sportogo makes them as 25" balls, AndyMark sells them as 2' balls.

They must loose an inch in Indiana air.

[Patrick Flynn]

Originally Posted by Brandon Holley

Has this actually been tried out tho? Its all speculation until you see the actual results.

I don't think anyone is asking for 10 decimal places of tolerance on the diameter.... However a single decimal place or 2 would certainly be welcome.

Honestly I would take one or the other if it helps consistency in an event and event to event. Right now, we don't have either besides a general 'look' and 'feel'.

-Brando

The actual result can be seem using chemistry.

Lets say we have a 25'' Sportlogo ball, and a 24'' AndyMark ball, I know their the same ball
R1=12.5in
R2=12in
V1=(4/3)pi(r^3)
V1=8181.23in^3
V2=7238.23in^3

Ideal Gas Law, PV=nrT
Assume (nrT) is constant between two balls.
We have have (P1)(V1)=(P2)(V2)
From above (P1)(8181.23)=(P2)(7238)
Notice the two pressures cannot be the same.
Lets say we inflate one ball to P1=7.5PSI, NCAA Basketball recommendation pressure
Now we see that P2= 8.477PSI

What does our result show? Well the Smaller diameter ball is at a greater pressure. Meaning that it is firmer.
If you try to instead control the pressure you'll see that you get stuck with a different ball diameter.

[Mr V]

Originally Posted by Jim Wilks

GTRW had a ball sizing ring. It was 25" in diameter and came with the field. I'm assuming other regionals had one as well. Was it being used?

We in the PNW district did not receive any sizing rings with our fields. I was there in the process of unloading all the stuff we received to inventory it and test it before repacking and loading on the truck. We never saw any such rings.

[Bochek]

Originally Posted by Jim Wilks

GTRW had a ball sizing ring. It was 25" in diameter and came with the field. I'm assuming other regionals had one as well. Was it being used?

After reading this I tried to inflate ours to 25". It would not get any bigger then 24" no matter how much air i put in. (almost to the point of bursting). Are the balls supplied by the field different than the ones supplied in the KOP? I sure hope not.