2016 Boulder weight issue

[Grim Tuesday]

This compression issue arose in 2012. Wise teams will design shooters that hit the target regardless of compression status.

[waialua359]

Originally Posted by catmanjake

Here are weights by color.
Yellow - 359
Orange - 326
Orange - 362
Purple - 358
Purple - 359
Blue - 388

I take it nobody else has received these yet to compare? Has anyone received multiple gray FIRST boulders yet to compare?

The Yellow and the 2nd Purple ones are good.

[electronicsdude]

Originally Posted by catmanjake

All,
Has anyone received multiple FIRST boulders or ones from Gopher and compared the weight? We received 6 of the Gopher balls today and they are different weights and only 1 was close to the official FIRST boulder we received in our Kit of Parts. Some of the weights are so different that we think that they will shoot differently. Let me know your thoughts.

For a ball meant for playing dodgeball it seems like a reasonable margin or error.

The solution in my mind is to minimize the projectile weight's effect on your trajectory. Basically shoot that s.o.b as fast as possible. Then you minimize the arc in the shot and hence minimize the necessity for a perfectly normal weight in your projectile.

Granted, this wont work if your ball is REALLY light or REALLY heavy.

[electroken]

Originally Posted by FYRERobot5480

We are wondering about the diameter of the balls, having only 1 ball, we can't compare weights, but the manual says the ball is 10" diameter, but ours is measuring as 9 5/8th.

Anyone else noticed this? We are wondering if it has to do with our altitude, (almost 5000 ft) and how competing at lower altitude could affect our shooter if the size changes this much.

The balls aren't sealed, or at least ours is not. It has one small (0.1" -ish) orifice in the outer covering, so I would not expect any difference in diameter due to changes in barometric pressure.

The ball that came in our KOP measures 9.7" in diameter at 300 feet above sea level and weighs 290g.

[James Juncker]

I'll attempt to weigh and measure my teams boulders but we bought a couple of the gray boulders and not the rainbow pack.

[GeeTwo]

Originally Posted by bobcroucher

We don't know how much of this is due to the older ball being broken in, but we don't believe that it ever flew that poorly even when new.

While we didn't take any measurements of it, I definitely remember our ball being much harder to compress on kickoff day than it is now. My initial impression was that it had about 3/4" of foam over a stiff core, now it's clearly memory foam all the way through.

[nakarsten]

We just received a six pack of the colored balls from Gopher. The are different than the original ball/boulder received in the kit of parts. The balls are heavier and significantly less compressible.

[The Doctor]

Originally Posted by FYRERobot5480

Anyone else noticed this? We are wondering if it has to do with our altitude, (almost 5000 ft) and how competing at lower altitude could affect our shooter if the size changes this much.

The surface is porous, so the boulders shouldn't necessarily change with altitude.

[Hallry]

Originally Posted by nakarsten

We just received a six pack of the colored balls from Gopher. The are different than the original ball/boulder received in the kit of parts. The balls are heavier and significantly less compressible.

Can you please weigh them and list their respective color?

[Schroedes23]

Team 1625 has 10 boulders ordered from Andymark and our 1 KOP boulder.
Our KOP ball has weighed in 281.22 g
Andymark Boulders
3 at 290.30 g
6 at 285.76 g
1 at 281.22 g

[Ether]

Originally Posted by Hallry

Can you please weigh them and list their respective color?

Your high school's chemistry lab may have triple-beam balances. You can get very accurate measurements with those.

My O'Haus triple beam goes up to 610 grams.

[JamesCH95]

Originally Posted by FYRERobot5480

We are wondering about the diameter of the balls, having only 1 ball, we can't compare weights, but the manual says the ball is 10" diameter, but ours is measuring as 9 5/8th.

Anyone else noticed this? We are wondering if it has to do with our altitude, (almost 5000 ft) and how competing at lower altitude could affect our shooter if the size changes this much.

For diameters see: http://www.chiefdelphi.com/forums/sh...d.php?t=141606

[Tyler Olds]

Wave Robotics Boulders:
KoP: 282.6 grams Edit: Just realized what this was and no it was not a joke. I think I got Glenn beat :-P

Boulders from AndyMark:
Boulder 1:285.8 grams
Boulder 2:284.9 grams
Boulder 3:278.5 grams
Boulder 4:290.8 grams
Boulder 5:291.7 grams
Boulder 6:280.3 grams

[Shu]

We recieved 9 orange balls directly from gophersport. We originally ordered the rainbow colored balls but received an email asking if we were an FRC team and asked us to correct our order. Out of our 9 orange balls, 8 weighed 0.62lbs(281g) and 1 weighed 0.60lbs(272g). The KOP boulder weighed 0.64lbs(290g). If you are ordering from gophersport the correct item number is 99-634 for the FRC version and they are ordered individually.

[Shifter]

MakeShift Boulders (from AndyMark):

Boulder 1: 284.4 grams 10" diameter
Boulder 2: 289.7 grams 10" diameter
Boulder 3: 285.6 grams 9-1/2" diameter
Boulder 4: 291.3 grams 9-1/2" diameter
Boulder 5: 287.5 grams 10" diameter