30" ball sits up there real pretty

FIRST General Forum
1

Posted by Raul at 1/12/2001 1:54 PM EST

Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.

When I was watching the game demo at the kickoff via satellite, I thought they said the big balls were 3 feet diameter. But the rules clearly state that they are to be inflated to 30". Was I dreaming during the kickoff or did anyone else hear that the balls were 36" dia.?

At the kickoff the big ball seemed to not easily stay on top of the goal and looked quite a bit larger than the top of the goal. We had 1 goal built on Sunday and it also seemed to sit up there rather tentively. But our ball was inflated to 36".

We just tried it last night while letting the air out of the ball to get it to 30". It made a hugh difference. We were able to let the goal roll down the ramp (bridge) by itself with a big ball on top and it never tipped over and the ball never fell out.

Raul

2

Posted by George at 1/12/2001 2:15 PM EST

Coach on team #180, S.P.A.M., from None and UTC Pratt Whitney.

In Reply to: 30" ball sits up there real pretty
Posted by Raul on 1/12/2001 1:54 PM EST:

I heard 36" also, but when I mentioned it, I was promptly rebuked by 3 or 4 team members with rule books in hand.

probably just a slip of the toungue at kick-off

George - SPAM Team 180

3

Posted by Ken Leung at 1/12/2001 2:16 PM EST

Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.

In Reply to: 30" ball sits up there real pretty
Posted by Raul on 1/12/2001 1:54 PM EST:

I think you are confused between the rules and Joe’s big joke about having 3’ balls in the game. Since it clearly stated in the rules that the ball are to be inflated to 30", then do not keep your balls at 36". At kickoff, even though the big ball sat on top of the goal peacefully, when the goal came down the bridge, it was really top heavy and refused to stay at its up right position. The goal felt right down on the bridge as it rushed toward the ground, and the ball felt out as well. You might want to check the kickoff video again to see. But at least I am certain that our goal reacted the same as the kickoff one’s. But then again, with the blue print supplied, no one can really build the exact field that will act perfectly like FIRST’s.

Is it possible that when you inflate the balls to 36" and get it back to 30", the balls won’t have the shape they are supposed to have anymore?

4

Posted by Matt Leese at 1/12/2001 3:05 PM EST

Other on team #73, Tigerbolt, from Edison Technical HS and Alstom & Rochester Institute of Technology.

In Reply to: 30" ball sits up there real pretty
Posted by Raul on 1/12/2001 1:54 PM EST:

Well, I won’t debate the fact that the rules say the balls will be inflated to a 30" Diameter (I haven’t seen it so if someone can give me a reference I’d appreciate that) but, if you look at the list of what’s in the kit, it says that the balls have a 34" diameter. The sport fun order form also lists it as 34". Something’s up here because that’s a pretty big difference.

Matt

5

Posted by Greg Young at 1/12/2001 3:27 PM EST

Other on team #587 from Orange High School.

In Reply to: The odd part
Posted by Matt Leese on 1/12/2001 3:05 PM EST:

Greetings,

: Well, I won’t debate the fact that the rules say the balls will be inflated to a 30" Diameter (I haven’t seen it so if someone can give me a reference I’d appreciate that) but, if you look at the list of what’s in the kit, it says that the balls have a 34" diameter.

The Game, page 1, last paragraph: “There are four (4) balls approximately thirty (30) inches in diameter. Balls will be inflated to size not pressure.”

I thought the balls were 34 inches as well. This changes some of my calculations.

Greg

6

Posted by Raul at 1/12/2001 6:15 PM EST

Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.

In Reply to: 30" ball sits up there real pretty
Posted by Raul on 1/12/2001 1:54 PM EST:

I called Eric to ask him to confirm the ball size. He said that the ball are advertised by the company that makes them as 34". However, he assured me that they definitely will be inflated to a 30" nominal diameter and about +/-2".

He said update #4 will probably come out on Saturday.

And if anyone does not believe what I just shared with you, then you do not deserve to live on my planet :-).

Raul

7

Posted by aTm at 1/12/2001 6:32 PM EST

Student on team #111, Wildstang, from Wheeling High School and Motorola.

In Reply to: I got an Answer from FIRST (Eric) - Big Ball size
Posted by Raul on 1/12/2001 6:15 PM EST:

I’m not too sure about this Raul character, doesn’t seem like the trustworthy type. Personally I still put forth the question will the balls be inflated to 3’ as i SWEAR i heard Dean say, or 30" like the rules say? I hereby erase from my memory that Raul already settled the question by going to FIRST directly, and will call them myself just to make sure. Haha…off to Neptune for me.

aTm

(this is just a joke, but for some reason, there are those on this forum that DO doubt Raul’s honesty)

8

Posted by 2PK at 1/12/2001 7:00 PM EST

Other from University of Ilinois.

In Reply to: Anybody Know the REAL truth?
Posted by aTm on 1/12/2001 6:32 PM EST:

I hate suck-ups. What about you aTm?
mwuhahahaha. j/k man.

9

Posted by Ken Leung at 1/12/2001 10:17 PM EST

Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.

In Reply to: Anybody Know the REAL truth?
Posted by aTm on 1/12/2001 6:32 PM EST:

From all the posting from Raul, I have to say he is totally trust worthy, even though I never meet Raul in real person. I am looking forward you see you at National, Raul!

Then again, everyone comming into this site should expect total honesty from other users. This site have been respectable for years, and it will remain as such for many more years, if everyone maintain their honor code.

10

Posted by Dodd Stacy at 1/12/2001 8:35 PM EST

Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.

In Reply to: I got an Answer from FIRST (Eric) - Big Ball size
Posted by Raul on 1/12/2001 6:15 PM EST:

I’m surprised by the +/- 2" tolerance on the big balls, but I’m REALLY confused about the small balls. We just blew up the 12 balls we have left from last year to 13" diameter and put them in our new goal, and there appears to be room for at least 3 or 4 more.

Our kickoff coaches swear only 12 fit in at kickoff. Is this a repeat of Ladder Logic, where the kickoff balls were overinflated and could be lodged firmly in the ladder rails, and the game balls were so much smaller they almost fell through? Any other teams have a data point here? How many small balls fit in your goal?

Dodd

11

Posted by Joe Johnson at 1/12/2001 8:56 PM EST

Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

In Reply to: Ball Sizes? What Gives?
Posted by Dodd Stacy on 1/12/2001 8:35 PM EST:

To use the word “diameter” in any sentence that
involves FIRST balls is wishful thinking indeed!

The balls that FIRST rarely have a single round
cross-section. Diameter just does not apply. One
might as well speak of the radius of a cube :wink:

For years, I have longed for FIRST to define the size
of the balls this way: The Circumference along the
equator (i.e. the parting line of the ball when it was
made).

To my way of thinking this is a very excellent
measurement system. Unlike the measurement systems
that FIRST has used in the past,
it is well defined for all shaped balls, easy to
verify and the gage needed to perform the readings can
be carried in your pocket (sting with a knot at the
right distance).

I believe we would all be happier if FIRST switched to
a rule that said, “The large balls will have a
circumference measured along their parting line (a.k.a.
equator) of 94.2 inches +/- 6.3 inches.”

I will spare you the rule for the small balls, but you
get the idea.

Any thoughts? Comments

Joe J.

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Posted by nick237 at 1/12/2001 10:07 PM EST

Engineer on team #237, sie h2o bots, from Watertown high school ct and sieman co.

In Reply to: Ball Sizes? What Gives?
Posted by Dodd Stacy on 1/12/2001 8:35 PM EST:

OK. I have the NASA video of the game and when they had teams being the robots one team pushed the goal to the human player to load. I freze framed a part where the goal was close to the camera and in full view.
All the balls stacked left right left right on top of each other and the total count was 11 but the top ball was just below the top of the goal and would stop a large ball from sitting purfectly on top.
With no large ball on top it would be possible to get one more in for a total of 12…
Assuming all the balls are the proper size.
nick237

: I’m surprised by the +/- 2" tolerance on the big balls, but I’m REALLY confused about the small balls. We just blew up the 12 balls we have left from last year to 13" diameter and put them in our new goal, and there appears to be room for at least 3 or 4 more.

: Our kickoff coaches swear only 12 fit in at kickoff. Is this a repeat of Ladder Logic, where the kickoff balls were overinflated and could be lodged firmly in the ladder rails, and the game balls were so much smaller they almost fell through? Any other teams have a data point here? How many small balls fit in your goal?

: Dodd

13

Posted by Ken Leung at 1/12/2001 10:30 PM EST

Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.

In Reply to: Re: Ball Sizes? real total…
Posted by nick237 on 1/12/2001 10:07 PM EST:

Being at kickoff, I remember counting 12 balls in the actual goal. But there are many factor that will affect balls counted in the goal.
First of all , not all the balls are inflated to the max. size, therefore different combination of different sizes balls will have a different toal volume of space occupied. Second, when people shaked the goal around with balls in, they actually managed to free some more space for one or two balls. Third, as Joe said, the balls are not a perfect sphere, and so stacking them in different ways can yield a different formation of balls. But then again, these factors might to small enough to not have any measurable effects. A word of advice is to try a lot of different situation and formation and see what happens. But most important is to similate how your robot put balls in too see how much it can put in.

14

Posted by ChrisH at 03/09/2001 5:04 PM EST

Engineer on team #330, Beach 'Bots, from Hope Chapel Academy and NASA JPL, J & F Machine, Raytheon, et al.

In Reply to: how about the ones with the old card?
Posted by Ken Leung on 03/09/2001 3:04 AM EST:

I was signed up last year and was told I had to do it again this year. If you don’t show up again in the database they assume you’ve dropped out and have no need of a new card.

Better get registered Ken!

Chris Husmann
Team 330 the Beach’Bots

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Posted by Rob DeCotiis at 03/09/2001 5:42 PM EST

Student on team #504, RoBUCtics, from Red Bank Regional High School and Jesel.

i got my first cut making these souveniers… (i only have 5 made, so im probably gonna have to have some sort of contest for who gets one…

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Posted by Dodd Stacy at 1/13/2001 9:39 AM EST

Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.

In Reply to: Re: Ballderdash check???
Posted by nick237 on 1/13/2001 12:19 AM EST:

: I would be a little worried if there were more than the 11 or 12 balls in a goal from what I saw.
: Are you sure the goal is the right size, what size did you make the goal and when you put the 2nd ball in, is the second ball partialy on top of the first or next to it?
: Next what height did you make the goal from the floor?
: nick237

The 2nd ball in sits partially on top of the 1st, and they stagger somewhat all the way up. We checked the goal dimensions pretty carefully as we went, double checking the drawing against the BOM lengths on the PVC. The goal is 7’0" floor to top, and the flange and tee centers are on a 25" dia BC. The BOM lengths on the vertical and horizontal PVC pieces were correct as listed to produce this result.

It may be that the verticals bow outward a bit in the middle, due to assembly inaccuracy while gluing up the PVC, but they look parallel. We’ll measure this.

Has anybody else tried how many of THEIR balls fit into THEIR goal?

Dodd

:
: : I thank Nick and Ken and Joe for confirming the 12 balls in the goal maximum at kickoff and for reminding all teams that SportFun balls are far from round.

: : I repeat my question. Have any teams out there inflated the small balls to however you wish to interpret the FIRST description of size and tolerance and determined how many will fit in your goal?

: : BTW, Ken, we loaded our balls by hand, over the top, repeatedly, while developing a good technique for quick loading by the HP over the barrier. It always came out the same - plenty more room after 12 balls (all we had).

: : And Joe, we cut a 13.5" diameter hole in a piece of 1/4" plywood and use it as a (barely) GO gauge on the minimum diameter of the “egg.” And even an egg, if it’s elastic and internally pressurized, is going to have one round cross section somewhere, right? So our balls are no smaller than 13", any way you slice them.

17

Posted by Patrick Dingle at 1/13/2001 8:59 AM EST

Other on team #639, Red B^2, from Ithaca High School and Cornell University.

In Reply to: Ball Sizes? What Gives?
Posted by Dodd Stacy on 1/12/2001 8:35 PM EST:

Last year, at all the official FIRST events I attended, the balls were overinflated (e.g. the balls had a diameter > 13" at the smallest circumference of the ball) Most times it was more like 14". I suspect FIRST overinflated both the big and small balls at the kickoff, and i’d expect the same at competitions.

Patrick

: I’m surprised by the +/- 2" tolerance on the big balls, but I’m REALLY confused about the small balls. We just blew up the 12 balls we have left from last year to 13" diameter and put them in our new goal, and there appears to be room for at least 3 or 4 more.

: Our kickoff coaches swear only 12 fit in at kickoff. Is this a repeat of Ladder Logic, where the kickoff balls were overinflated and could be lodged firmly in the ladder rails, and the game balls were so much smaller they almost fell through? Any other teams have a data point here? How many small balls fit in your goal?

: Dodd

18

Posted by Rick Gibbs at 1/13/2001 7:10 AM EST

Engineer on team #145, T-Rx, from Norwich High School, Sherburne-Earlville High School and Procter & Gamble Pharmaceuticals.

In Reply to: 30" ball sits up there real pretty
Posted by Raul on 1/12/2001 1:54 PM EST:

A couple years ago, my son got a ‘Bigen’ for Christmas in its original box. I remember saying, “Hey look - Sport Fun - Boy I hope FIRST never gives us those!” Anyway, if I remember right the box said that it should/could be inflated to 32-36". Maybe that’s where some of the confusion comes from.