Close Inspection

[Mister_Juggles]

I remember last year (06) our robot was weighing in at a tenth of a pound or so overweight. We let the air out of the pneumatics and it put us *just* under 120

[Tristan Lall]

Originally Posted by Mister_Juggles

I remember last year (06) our robot was weighing in at a tenth of a pound or so overweight. We let the air out of the pneumatics and it put us *just* under 120

That shouldn't have worked. Assuming that you have two Clippard AVT-32-16 tanks with 16 in³ each at 120 psi, and four 24 in stroke, 2 in bore Bimba Cylinders on board (realistically, that's way more than you'd expect, even neglecting the tubing), at 120 psi and 60 psi respectively, the amount of air on board is only about 0.06 lb.* If you went from 120.1 down to 119.9 ("*just* under 120"), there's a leftover 0.14 lb to be accounted for. More likely, you just got lucky with the error in the scale.

And here's a question to which I don't really want to know the answer: do you need to weigh the robot with or without its compressed air?

*This assumes an air temperature of 21°C; in reality, the air is probably hotter than this due to being mechanically compressed. And that lowers the density even more.

[Wayne Doenges]

We let the air out of the pneumatics and it put us *just* under 120

That happened to us this year at Boilermaker. We were 120.2 pounds. We were told to let the air out of our three clippard tanks. We than weighed 120.0 We have to have our tanks filled because we use the air to back fill our cylinders to keep the gas struts compressed
We also always build 1" short of the width and length dimensions. We have never been too big but we have removed plexiglas from the box due to bolt heads