Pneumatic

[maddox]

Pneumatic

Chad, in the UK and the Netherlands several of the 12 kg (26.5lbs) featherweights use full pressure CO2 pneumatics. They are in the end not that much more expensive than low pressure and they give a lot more OEMPH for the weight used for them.

On the other side, I do have a reasonable supply of Low and High pressure rams ,valves and buffertanks. Everything between 100 and 1000 psi. Mail me for more information.

[wazio]

Pneumatic

E-mail sent. If you ever get on yahoo my AIM name is wazio88

~Chad

[big_nipper]

Pneumatic

Chad, The super secret UK regs that we use is the stabilizer as well . Weve managed to freeze the reg even with a buffer tank but only on lower than 50psi and after 20 or so hits with the axe in a row. Other than that weve never had a problem with them. The only thing to note is they are not the reliving type so any liquid getting passed the reg will cause a greater pressure than expected so you need a good pressure relif valve.

[woody]

Pneumatic

Hi again Chad,
I suspect that Mario has already sold you F.P. setup or perhaps a QEV powered L.P?
If I can be of any assitance ......feel free to email via the link on my profile.

[mightymouse]

Pneumatic

A good place for valves is RS - a bit pricey but good quality.

I have made my own regulator based on the palmer design and it gives such a good flow rate that I do not need a buffer tank, I am not sure whether a palmer reg could be modified to my spec. I dismantled a standard ram and fitted a spring inside to retract the flipper.

The main valve is of my own design but prior to that I used a 20bar 24v solenoid 2/2 valve(technobots) and a drilled hole in the ram feed to vent. This set up was capable of turning over any other machine, and if fired without a robot on top it would land me on my a**e.

I will put an image of the machine self-righting on my profile.

Feel free to e-mail me if you want to know more.

[woody]

Pneumatic

Trev ......Chad is U.S. based.

http://www.mcmaster.com/http://www.mcmaster.com/ is probably better.

(Message edited by woody on September 29, 2005)

[wazio]

Pneumatic

I have been looking at the numbers from other pneu bots (in the US)...

So here they are

Judge: 60,319 lb-inches
Ziggy: 56,549 lb-in
Bounty Hunter: 84647 lb-in

So if I scale that down to a 30lb bot, That would put me in the 5000 lb-in range.

So, now I narrow my question... What do I have to do to get 5000 lb-in? (at the tip of my arm). The bot will use a 4 bar system, not the usual cylinder in the front, arm mounted at the back.

~Chad

[kevin]

Pneumatic

Whats a low pressure for a feather flipper. I was thinking of 100-150psi. How long would it take to flip a 12kg robot at 100psi forward?

[wazio]

Pneumatic

Or if not 5000lb (might be to high of a goal), then enough to launch a bot 8 high Or tip over a bot double its weight... Large goals, I know.

~Chad

[mark_m]

Pneumatic

Heres some quick calculations I just did out of interest:
5000lb-in is approximately equivalent to a ram with a swept volume of 33cubic inches at 150psi. This is approximately equivalent to a 3 bore and 5 stroke.

5000lb-in is also equivalent to a 30lb robot, 167 high (14 feet or 4.1m).
But from the crude analysis other people have done on Wheely Big Cheese, Gravity and Chaos 2, you can only get an efficiency of about 50%, so in reality if you put in 5000lb-in, the other robot will go about 7 high.
I think LP systems are typically more efficient than HP but I dont have any real experience or data to support this. Im sure a 4bar system will be less efficient than a basic rear hinged flipper.
So in actual fact your aim of 8 is more ambitious than 5000lb-in.

So two 1.5 x 6 rams may be nearly adequate.

Mario is probably the best person to advise you on this though.

[woody]

Pneumatic

Fairly meaningless figures without a time constant.
But lets work on the assumption that you supply your 5000 lb-in effectively .......so thats 416 lb-ft .........your chucking a 30lb bot
416 divided by 30 ......thats close to 14 feet
then assume 50% efficiency ...7 feet of potential throw.

A 2 bore ram with a stroke of 8 running @ 200 psi matches your throwing requirements and would produce 628 lbs of lift ......more than satisfying your last requirement.

So its a question of matching up a decent size ram with a valve that will flow enough to fill it in a VERY short time..... i.e. tenths of a second.

I believe that a valve and pipework with a Cv of 5 or more together with the 2x8 ram would do the trick.

Seems Mark beat me to it .........

(Message edited by woody on September 29, 2005)

[mark_m]

Pneumatic

Its nice to know we both got the same numbers independently though!

[woody]

Pneumatic

@ Mark
Yep .....a perfect match



(Message edited by woody on September 30, 2005)

[woody]

Pneumatic

Chad .......How much wieght can you dedicate to the pneumatic ssetup?

[wazio]

Pneumatic

I would like to keep it around 10 pounds if possible, but as everybody knows... Less is better. 10 would still give me weight for a half good frame and some ok armor. Their are some 30lb spinners that are just crazy with the amount of energy they pack! But I think it would be good to see them flying about 5 in the air