Does this only ever happen to us?

[russell]

First some explanation: I am currently in my second year of FIRST, and on a second year team. We are still trying to finish our robot, and it looks like we will make it in time, but now I am getting off topic.

My point is that today I realised that both this year and last year we had a wonderful robot designed with all sorts of wonderful mechanisms each of which should work wonderfully. And the total of the weights of all the mechanisms is not even close to the weight limit. Then we put all the mechanisms together, and while it all works OK we realise that we are overweight, and this or that part weighs a lot and doesnt really gain us much so just like that there goes half the robot. In the last two days we have gone from having a wonderful unique awesome looking machine, to having a rectangular prism, with wheels and a stick it can wave around.

Do other teams have this problem or is it just us? One of our problems is that we dont really design things, or when we do we dont design them to work together, we just design individual parts, then find a way to bolt them together later. But even so, it is still odd...

[Billfred]

In 2004, 1293 pretty much built on the fly. We didn't know squat about preseason mockups, what was in the kit (beyond "motors"), or planning what we were going to put on top of the robot before putting together the bottom. And the result was just as you described--a rectanglar prism with wheels and a stick it can wave around. (Although, given our 3-4-1 record at Palmetto, that was one heck of a rectangular prism with wheels and a stick to wave around.) We weren't overweight, mainly because we didn't build too much on the robot.

In 2005, we know what we're doing--but still didn't do up much in Inventor. Before Kickoff, our grand scheme was to use 8020 to build the frame, but JVN and Paul Copioli changed that plan quickly. The robot is a lot better--but we're fighting the weight war (currently losing by about five pounds).

In 2006, I suspect that 1293's Inventor folks will be sleeping as much as 1293's college student did in the late part of the 2005 build season. (I kid, I kid.)

[Warren Boudreau]

It happens. Especially to young teams that don't have the benefit of experience of nearby older more experienced teams.

Over the years, we have identified some of the major culprits of designs going overweight. One is the controls and wiring. Everyone forgets that wire, and speed controllers and the RC all weigh something. Fortunately, this year you don't have to worry about the battery. That one is a biggie to miss on. Another culprit is mounting brackets and fasteners. It doesn't sound like much, but it all adds up.

About the only thing that you can do at this point is take off stuff until you make weight and it sounds like you did that. Then go through and figure out where you missed on your weight estimate.

[Rick TYler]

We are a sophomore team that spent a day (and a night) last year drilling out our aluminum frame to meet weight. A ziptie would have put us over.

This year, we started weight engineering from the very start. We substituted laminated wooden parts for aluminum in some places where we needed extra stiffness, and generally tried to keep things simple. Our robot is basically a rectangular pizza box with a tower sticking up on one end.

The first time we took the tower, arm, and chassis components to the scales, complete with all electronics and pneumatics, we came up at about 95 pounds. By the time we actually fastened everything together, it was around 105. We held off adding bumpers until we knew the preliminary weight, so we then built wooden bumpers that were designed to weigh about 10 pounds. Our final weight (right now) is about 118 pounds after a last-second addition of some extra "shielding" over our electronics after seeing team 492's 18-inch-long pointed aluminum spear they use to lift tetras.

The best way to meet weight is to think about it at every step of design and construction, and then weigh and tabulate components frequently. I also suggest shooting for a really low weight (our target was 100 pounds) so that when you inevitably start adding features, it will still keep you under the real limit.

One of the 'bots at the PNW practice tourney was 16 pounds overweight. We really feel for them. Been there, done that.