Pneumatic

[babeth]

Pneumatic

Getting a bot up in the air is not that impressive, a bit overrated even. Its the coming down that must be spectacular. Cant throw them high enough in my opinion, because what goes waaayyy up goes mightily down.

[kevin]

Pneumatic

What lasts longer? Air or Co2? I have been told air but this person could be wrong. How expensive is a 600g Co2 bottle usually?

[maddox]

Pneumatic

Depends on maximum storage pressure for the same size of storagebottle.
If its 1000 psi CO2 wins hands down. If it goes over 4500 psi, air wins.
CO2 goes liquid at room temperature and increases density with a factor 10= compared to the compressed CO2 gas on that pressure.

Imagine a 3L bottle. Rules say you can fill this bottle with 2 kg of CO2, or 3L of compressed air on 1000 psi/70 bar. With air you have 3liter*7a bar =210L of gas.
With CO2 you have 2 kg=512L gas per kilo, so 1024L gas in that same bottle.

To beat this with compressed air youll have to go over 337 bar.

600grams CO2 bottles, 20oz paintball bottle with On Off valve can be bought over here around ‚45.

[kevin]

Pneumatic

Are the CO2 bottles already at a certain pressure, say 1000psi? If so, how would I bring the pressure down to 150psi for the whole system?

[philip_taylor]

Pneumatic

Listen to Mario. You will find it is cheaper, lighter and simpler to go with full pressure CO2.

You could buy a paintball regulator, like the Air America Messiah, but this adds expense, weight and complexity for no benefit.

[woody]

Pneumatic

http://www.teamdavinci.com/understanding_pneumatics.htmhttp://www.teamdavinci.com/understanding_pneumatics.htm

[wazio]

Pneumatic

Ok, after much talking with Woody and Mario I have made up my mind to go with a FP system. Mario is going to make me a Cylinder that has a 70mm bore and 100mm stroke. I will also use AL paintball tanks it keep the weight down. I think that I should be able to keep the whole system at about 10 pounds. I hope to get another robot to fly about 10 in the air with this large cylinder

Now I need to figure out how to mount it all up. What do you all believe to be the best system? By far the best flipper in the US was the Toro guys. I was thinking about a mini T-minus.

http://www.robotcombat.com/images/bbsf02/large/t_minus.jpghttp://www.robotcombat.com/images/bb...ge/t_minus.jpg

Do you all have any other advice on the type of arms and angles? And pictures of other featherweight bots so I can see what has been done before?

Thanks!

[ewan]

Pneumatic

Hi Chad,

Theres a picture up on my profile now of a featherweight FP flipper tossing another featherweight into the air. This one is named little flipper, and has a rear hinged flipper with a big ram (something like 60mm bore?) and lots of gas flow. Thats the kind of thing Id be aiming for to make things fly - there hasnt been any toro style featherweight flippers in the UK though, so its very hard to compare the two flipper designs.

[philip_taylor]

Pneumatic

Chad, you had better fit a parachute for self-righting.

[wazio]

Pneumatic

LoL, I will have to find weight for that somewhere I figure 10lb for pneu stuff, 5lb for my kevlar/Ti armor, 1for a batt, and 4 for drive. That leaves me with 10 for a frame and whatever else. oh, and a parachute.


~Chad

[knightrous]

Pneumatic

Quote:Mario is going to make me a Cylinder that has a 70mm bore and 100mm stroke. I will also use AL paintball tanks it keep the weight down. I think that I should be able to keep the whole system at about 10 pounds. I hope to get another robot to fly about 10 in the air with this large cylinder



Marauder has a 70mm bore 50mm stroke Maddox ram in it and I can vouch for a fact that it can launch 30lb (13.6kg) robots 5-6ft into the air! I had my own robot launch into the polycarb at my own face height (Im 6ft tall) and this was not a pleasant thing to have happen. Watching Marauder selfright from one side of the 4m arena to the other side was pretty spectacular too

Mario builds some top quality pneumatics, so you wont be dissapointed!

[kevin]

Pneumatic

Do I need to do any calculations for a high pressure system, or is it trial and error?

[maddox]

Pneumatic

Depends Kevin. It all depends on what you want.

I dont bother about calculations. I let experience talk.

[philip_taylor]

Pneumatic

Kevin, you could tell Mario how high you want your bot to throw the opposition and ask him how much he would charge to build the pneumatic system.

Designing your robot around the weapon is a good idea.

[kevin]

Pneumatic

I still think that a front hinged flipper would be effective on a featherweight. I think flipping a robot in the air plus OOTA is just showing off.