How much does your robot weigh?

[Koko Ed]

116 pounds (most likely 118 when the signage is added at FLR).

[ttakashima]

We are at 122.5 lbs. We kept the shooter back, it Currently weighs 21lbs which in my opinion is very heavy. We have many holes to drill! We also still need to add our 2lb side plates at the comp with our sponsor logos!

[ThirteenOfTwo]

103 when we weighed without the wiring (but with electronics like CRIO/radio/jags), 108 when we put expected wiring materials on the scale too. Sixteen-pound withheld intake and eleven-pound withheld scoring mechanism leave about 80 lbs in the bag right now. At least eight of the withheld pounds come from COTS gearboxes and motors which will be brought to competition not as a part of the weight allowance.

[Cal578]

We were at 119 lb with a couple days to go. Since the scale didn't seem to be quite accurate, and we can't be 100% sure that our manual calibration is perfect, being that close to the 120 lb limit made us a little nervous. Even if we believed our scale was perfect, it may not be the same as the one used by inspectors at competition, and we can't argue with their scale. So, we worked on a few things to give us some safety margin.

Many people talk about the "swiss cheese diet". Here are some points to consider:

1. Drilling holes shouldn't be your first option. We changed to a lighter sprocket, and made a lighter mount for the camera. These were engineering improvements, in addition to saving weight.
2. It takes a lot of holes in plastic to make any difference in weight, and that often compromises strength before much weight is shed. Target metal, especially thick items, first.
3. You can remove weight from any part of the main robot to get under the limit, but the location of the removed weight can impact performance. Removing weight up high makes your robot more stable and easier to balance. Removing weight down low can make things worse.
4. If you have decoration like lights, they count against the weight limit. We have some cool lights that everyone likes, but we had to make the decision that if we're overweight at competition, lights are the first thing to remove (I really hope we don't have to, they look too good). You might be tempted to remove panels that display sponsors, but remember that [R04] requires displaying school and sponsors during competition (plus, it's just right).

Good luck, everyone!

[artdutra04]

Originally Posted by Cal578

[*]It takes a lot of holes in plastic to make any difference in weight, and that often compromises strength before much weight is shed. Target metal, especially thick items, first.

Don't be so quick to immediately discredit lightening plastic components; if the plastic part is large enough, the weight savings become valuable. If you have sheets of Lexan/polycarbonate on your robot, these add up almost deceptively quick in the weight department.

For example, a 24"x36" sheet of 1/16" polycarbonate weighs in at just under 2.4 lbs; the same size panel from 1/8" polycarbonate weighs in at about 4.75 lbs (which is about the same weight as the older Thomas air compressor).

Be warned through: while it is possible to use large hole saws (2-3" diameter) in sheets of Lexan, it's not the easiest thing to do in the pits. It's much easier ahead of time to only use the thinnest possible Lexan.

[Cal578]

Originally Posted by artdutra04

Don't be so quick to immediately discredit lightening plastic components; if the plastic part is large enough, the weight savings become valuable.

I'm not discrediting it; I'm actually agreeing with what you just said. It would take a very large piece of polycarbonate to make a good target for weight savings, and then you need to put lots of holes in it to make a difference. If you have large metal pieces on your robot (sprockets, plates, mounts), you can get more weight savings with fewer, or smaller, holes. I've seen several teams (including mine, four years ago) drill a bunch of holes, get reweighed, and find that they hardly made a difference.

[MrForbes]

We took about two pounds of Lexan off our shooter...we didn't cut holes in it, we just cut off the excess material that wasn't needed.

As usual, you have to keep weigh in mind all thru the design and build process. If you do this, you shouldn't have a weight problem. We have a really heavy steel chassis, but we're still underweight, because we were pretty careful to use mostly only light materials on the "upper" parts of the robot.

[Garret]

Without the motherboard for controlling the camera our robot came in at 105 lbs. Very surprising for the amount of stuff on the robot this year.

[Ekcrbe]

Originally Posted by CalTran

Well, 15ish lbs, give or take

The last battery I checked that we had was 12.55 lbs, but I haven't averaged any more.

[gracie.]

Our final weight before bag & tag was 111 lbs. With the extra bumper and battery weight to lower our center of gravity, we're not too worried to be under the weight limit. If you're over, the universal advice is to start drilling holes. We've done it in the past, and I'm sure we'll do it again. Start with lightweight stuff in the first place, and if that fails, bring large drill bits.

[JamesCH95]

Originally Posted by Ekcrbe

The last battery I checked that we had was 12.55 lbs, but I haven't averaged any more.

FWIW 95's rule of thumb, from the old-school days when we weighed robots with batteries, was 13lbs/battery with the typical-length 6awg leads. Some batteries could be up to 2lbs less than this if they were older.

I definitely agree that 15lbs is a a few lbs too generous for battery weight.

[kendra21093]

121.2 LBS...WHYYYY??????? D:

[reymac]

We are at 105 pounds. We may consider adding weight to our robot depending on its performance in practice rounds

[stundt1]

We are around 120 pounds. Our scale wasnt calibrated correctly so we are really unsure but we should be around the 118-120 pound area.

If we are over our cathodes and side panels will the first to come off. Though if we are under weight we decided we might add a second camera to assist the operator and driver.

[peter1626]

Three days before the deadline we finally got a hold of a scale... We were 139, after redesigning the entire front of the robot and the pickup system then we removed the protective 1/4" Plexiglass and replacing it with 1/8" with holes we were 118