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Brad Team 2520
01-30-2008, 11:05 AM
Hey. We need to know what the height of the lowest point of a track ball is whilst it is suspended on the rack. I cannot find this anywhere in the rules, or diagrams, so can anyone help me clarify this? How high is the lowest point of the crossbeams that transverse across the field? It was said that they are 6 and a half feet high, but I want to know to what point on the bar, if that makes any sense.

Anyways, thanks.

Donutboy
01-30-2008, 11:14 AM
the height of the overpass is 6'6" on center(center of the tube). The piping is 1.5" therefore the lowest point is 6' 4 1/2".

Rich Wong
01-30-2008, 11:17 AM
The bottom of the ball is actually 6 feet to 6 feet 2 inches from the ground.
Some trackballs are rounder or flatter than other trackballs.
:]

Ty Tremblay
01-30-2008, 11:34 AM
About 70". There is no exact height, since the balls could vary in air pressure, or they could be pushed down into the overpass.

EOC
01-30-2008, 12:00 PM
According to the FIRST Q & A forum the top of the overpass pipes is 6'6"
http://forums.usfirst.org/showthread.php?t=8058&highlight=overpass+height

Zultraranger
01-30-2008, 01:57 PM
The bottom of the ball is actually 6 feet to 6 feet 2 inches from the ground.
Some trackballs are rounder or flatter than other trackballs.
:]
This might sound stupid, but the trackballs aren't identical to each other? I didn't know some could be rounder or flatter.

Also, why would FIRST give each team a ball if it was not identical to every ball on the playing feild? Some teams might make a device that fits perfectly around the shape of the ball. Therefore, if some ball's shape is altered, it could mess up their robot's stategy completely.

EricH
01-30-2008, 02:03 PM
This might sound stupid, but the trackballs aren't identical to each other? I didn't know some could be rounder or flatter.

Also, why would FIRST give each team a ball if it was not identical to every ball on the playing feild? Some teams might make a device that fits perfectly around the shape of the ball. Therefore, if some ball's shape is altered, it could mess up their robot's stategy completely.
People thought the same thing in 2004. Those playground balls became elliptical within a day.

The deformation of the trackballs is part of the game challenge. The ones given to teams are as close as possible to the ones for the field. Identical, even, until the end of Thursday, maybe. But then they will deform. The challenge is to handle them while they are deformed.

Brad Team 2520
01-30-2008, 04:23 PM
Thank you guys! This was very helpful.

EricH
01-30-2008, 04:25 PM
the height of the overpass is 6'6" on center(center of the tube). The piping is 1.5" therefore the lowest point is 6' 4 1/2".Wish I'd seen this sooner... The height is to the top of the overpass, according to Q&A.

GBIT
01-30-2008, 04:33 PM
seeing that the ball rests on the top of the pipes. We found the hang to be (assuming the the 6.5' overpass is on center with the pipes) it would hang only 1.5 inches below the 6' legal limit. If the 6.5' is at the bottom of the pipes it would hang only .67 inches from the 6' limit. this is assuming the the ball in of 40" diameter.



here is the diagram:
http://www.chiefdelphi.com/forums/attachment.php?attachmentid=5926&d=1199655203

EricH
01-30-2008, 04:35 PM
seeing that the ball rests on the top of the pipes. We found the hang to be (assuming the the 6.5' overpass is on center with the pipes) it would hang only 1.5 inches below the 6' legal limit. If the 6.5' is at the bottom of the pipes it would hang only .67 inches from the 6' limit. this is assuming the the ball in of 40" diameter.



here is the diagram:
http://www.chiefdelphi.com/forums/attachment.php?attachmentid=5926&d=1199655203
What 6' limit? I would advise a re-reading of <G36> in the current manual.

Wayne C.
01-30-2008, 05:52 PM
I measured 69 in at the kickoff to the bottom of the ball

Rich Wong
01-31-2008, 12:04 AM
This might sound stupid, but the trackballs aren't identical to each other? I didn't know some could be rounder or flatter.

Also, why would FIRST give each team a ball if it was not identical to every ball on the playing feild? Some teams might make a device that fits perfectly around the shape of the ball. Therefore, if some ball's shape is altered, it could mess up their robot's stategy completely.

I have seen several deformed trackballs at a couple of schools.
Some were even damaged after several team members used it as a bean bag.

At the regionals, the trackballs are close to perfect but expect some odd shapes by the end of the event.
:]