pic: How 1251 shipped.

[miketwalker]

Originally Posted by sanddrag

The brand of your transmission has absolutely nothing to do with the number of times you can shift it before your air runs out. Anyhow, what pressure are you shifting at? Last year, we shifted at about 45 PSI and got 12 shifts out of one tank. How can you get well over 100? You must have been shifting at a low pressure. We started at about 100 psi in the tank, took 12 shifts, and ended under just 45. But anyway, 12 shifts is shifting once every 10 seconds. So, if shifting is your only pneumatics, you can probably get by with one tank.

I mentioned the transmission because we used the AndyMarks which means you just need to use the 1/2" cylinders. If they did custom ones they might need larger which wouldn't work as well. If you check for air leaks and pump the PSI to the amount allowed it should last for a good number of shifts.

[Stephen P]

There is alot of aluminium support structure you can take out of there and still retain structural integrity. We dropped about 20 lbs just losing extra aluminium bars. Just think minimalisticaly.

[Cory]

I'd second what everyone else is saying. If you're only using pneumatics to shift the trannies, ditch the compressor, and precharge one accumulator before the match. We're getting ~50 shifts off of one accumulator, regulated down to 20 PSI.

Someone suggested taking off the AndyMarks in favor of the kit gearbox. I don't know how much one of their current transmissions weighs, but I'm pretty sure an AndyMark is less than a KOP gearbox.

[techtiger1]

The transmissions use a 1in stroke piston, which is larger then the Andy marks use .75in inch stroke I believe. The wheels for Sanddrag's information are uhmw and were very cheap to make thanks to our machining facilities, they were done with a CNC mill and we just bought the stock which ran under $200.

-Drew

[KenWittlief]

Originally Posted by Cory

We're getting ~50 shifts off of one accumulator, regulated down to 20 PSI....

Might want to check the specs on the pneumatic valves - I think they are rated for a minimum pressure of 30psi? Maybe it was only the big valve but its something to look into.

If the valve only switches half way all the air in your tank will leak out.

[Jay W.]

What what I can see, you've got the an excellent design, you just need to get it together/skinnier!

When we get to Florida, just look for us and we'll be glad to help. Heck, we'll have plenty of people un-crating our machine, I'll come help ya'll out (maybe if theres a T-shirt involved j/k :-P).

my e-mail is jayw(AT)famview.com, if you think of anything, just shoot me a message.

cya at UCF,
~Jay

EDIT:

Just thought of something, could you ditch the compressor and just refill an air tank(s) in between matches?

[Andrew Rudolph]

Maybe you guys could rebuild that structure using 1/16 wall aluminum, it looks thick in the picture.

You guys are a great team and I am sure you will be really competitive shooter or not.

[Chriszuma]

Here's some ideas for you:
- Replace the big CIMs with smalls ones - there's a few pounds right there (they have more torque too)
- Ditch the compressor and just pre-fill- thats about 6 pounds
- The big A-frame you've got going looks kind of unnecessary. You could probably make it much smaller.
- It looks like you have way more metal than you need on the hopper.
- Those are some incredibly massive transmission plates and mounts. Drill big holes in them.
- You can use much smaller chains. Ours are about half that size, and we've never had problems with breakage.
- You might have to ditch that machined nameplate on the front. It looks like it weighs about 10 pounds; at least use thinner material.
- It looks like all your square bar is 1/8" walled, and you can definitely get away with 1/16". It's probably a bit late to change that though.
- If you can, machine down the gears in the gearbox. By taking down the hub and putting a few holes in them, you can cut them down from about a pound each to about a third of a pound.
- Fill the air system with helium!!

- Edit: you can run the shooter with only one motor, with a chain to each wheel. We are running ours (same horizontal setup) with a single FP motor on a custom gearbox.

[jcatt]

Thanks to everyone who has given us advice so far.

As of right now we are a few pounds under!!(Sigh of relief)

As for the competition we plan to modify our hopper to hold A LOT more balls and we will be keeping the large bike motor in the gearbox so we can remain to be a strong defensive robot.

Thanks again for all the support.

The TechTigers

[Dillon Compton]

Hey- Dont worrry, you arent the only team in this situation (we shipped with a robot that would be expected in the middle of week 5, at best...). An excellent way we found to cut weight was to replace our heavier box and extruded aluminum with (i think it was 1/8" wall) inch box aluminum with a 3/8" speedhole ~ every 3/4"(on all 4 faces). We used our drillpress, took an hour to do all the pieces we needed; just look at where you will need to attach and dont speedhole there, because you will need to throughbolt. This brought the weight down to about .1lbs/foot for material that wont be taking a beating (hopper frame, stuff inside your 'bot profile, etc...)- heck, it's even pretty strong- I am about 240-250lbs, and I held a 3 ft length of speedholed box at an angle on the ground and stood on it, so it was supporting all my weight and being levered against my foot, and it took me about 5 mins of continuous pressure to get a relatively slight bend.

Good luck, and remember, if nothing else, defense is always useful!

[David Guzman]

Thanks everyone for the support. Just to answer some questions and suggestions.

-The wheels are made out of UHMW and the came out to be about $12.00 each and about 1.5 hours of CNCing each one. Also each one weight just under half pound so taking the middle one out wouldn't make a big difference.

-The shooter can not come back on because of the way it was taken off, when we started "the diet" many welds were cutted and makes it impossible for some pieces to come back on.

-As shown in the picture (plus electronics, and storage tanks) the robot weights 109 lbs so we don't have the need to remove pneumatics. Also we will be using the air for a dump truck design.

-We are planing on putting a dump truck in the back of the robot at UCF and we think of cutting up the current hopper to suit our needs.

-Also the paint job looked great before the diet.


Thanks everyone for the support and we have tons of work for Thursday.

No matter what happens to the robot we learned our lesson and we had fun. That's what matters, we still think we can make this a very competitive robot but we were expecting to have a killer machine as you can see on the other pictures. Sometimes we have to go through rough things to become wiser and well as much as i don't like to cut our bot to pieces it was needed to learn our lesson. We are also proud of this robot because it was all student designed, student machined and student built.

Good Luck to every one.

Dave