Worried about weight ?

[xXhunter47Xx]

We've started to strip unused conductors from CAT5 cable to save weight

[s_forbes]

Maybe we'll invest in some balloons. Size limitations this year are great!

[Donut]

73 pounds. We still have to make our forks/tote grabber with the withholding allowance to bolt on Thursday and some sponsor panels but our critical systems aren't even going to get us to 100. Which means lots of room for a counter weight!

[Sperkowsky]

Funny we were not worried about weight the entire season. We weighed it today and it was 117 pounds........ Well that could have been bad.

[jimbo493]

We came in at about 119.5 So we are a bit worried since we like to leave a little for varying scales, but we cut about 3 lbs today to get us into the legal side of things, at the start of the meeting we were 123.

[Tristan Lall]

Originally Posted by s_forbes

Maybe we'll invest in some balloons. Size limitations this year are great!

As I'm sure you know—but in case others haven't considered this—weight does not include buoyancy. Our conventional methods for measuring weight don't account for that source of error, but with most robots it's negligible.

If you bring an inflatable robot to inspection, I wouldn't be surprised if the inspectors make you calculate the weight of the contents of the gas bag, and incorporate it into your official weight.<sup>1

1</sup> By implication, the gas bag can't be a pneumatic part (arguable, depending on the robot's configuration), and the gas is a part (and by further implication, so should be the air in your pneumatics). To avoid those inconvenient complications, instead use a large, lightweight chamber full of vacuum.

[dtengineering]

Originally Posted by Tristan Lall

As I'm sure you know—but in case others haven't considered this—weight does not include buoyancy. Our conventional methods for measuring weight don't account for that source of error, but with most robots it's negligible.

.[/size]

I find myself compelled to disagree.... which is probably a sign that I should really be doing something useful or productive instead, but hey... this is more fun.

The FRC standard for measuring weight is to place the robot on a scale. In keeping with FRC precedent and in lack of guidance from the Q&A, I'd have to assume that the manual specifically chose the word "weight" rather than the word "mass" because the rule reflects the method of measurement.

Of course if FIRST was based on international standards for science and engineering, they would have a rule requiring the robot to have a mass of 55kg or less, and the point would be moot. Even specifying a weight of 55kg or less would imply a mass of 55kg or less as the gram is specifically a unit of mass, not a unit of force. The pound is an imprecise unit specifying neither mass nor force. Given that the people who wrote the rules are aware of the difference between mass and force and chose to go with an ambiguous term, it is only fair to conclude that they did so intentionally and give the benefit of the doubt to the team.

I also feel compelled to argue for the legitimacy of the balloon as a robot component. Other pressurized vessels, such as gas shocks and pneumatic tires are allowed, so long as they are not connected to the robot's pneumatic system. In the event that a sealed balloon was disallowed for some reason, there is no requirement that the buoyancy come from a sealed vessel. Hot air balloons work nicely with an opening.

I will now remove my tongue from my cheek before it causes permanent disfigurement!

Jason

P.S. The "anchoring" thing wouldn't work, however, as the robot must meet the weight limit in its starting condition. This might cause some grief with maximum height requirements.