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Hellcat - Hellfire Labs - QLD
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kkeerroo
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Joined: 17 Jun 2004
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Hellcat - Hellfire Labs - QLD

Now that I have finaly got that Prancing Queen stuff out of my system it is time to start something a little more serious.

This robot will be a pneumatic flipper but is still in the POP stage.
Drive: HTI motors on SS2 gearboxes driving 95mm wheels (the same setup as in the last version of Hellbringer).
Batteries: 24V 3300mAh NiMH.
Chassis: Steel frame with dual layer polycarb armour.
Weapon: 100psi pneumatic flipper supplied by a 20oz CO2 paintball bottle via a drop-foward mounted style paintball regulator. The supply tubing will be 1/4" to the buffer which is a 1kg fire extinguisher, then 3/8" to the valve (and it is a beast of a valve).
The ram is the only part that I am still waiting on. I bought a 40mm bore SMC ram off ebay for $10 but it has not yet arrived.
Sorry that there is no pictures of what I have but we had a break-in here and lost quite a lot of camera/video gear. Crying or Very sad
I plan on having this robot ready for the Ideas Festival thingy so watch out!
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Post Sat Feb 04, 2006 6:17 pm 
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Philip
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Joined: 18 Jun 2004
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Location: Queensland near Brisbane


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Are you sure you want a 20 oz? I would have guessed a 3.5 oz bottle would be more than you need.

I can't wait to see what you build.
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Post Sat Feb 04, 2006 6:35 pm 
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Knightrous
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20oz bottle running a 40mm bore.... You'll be able to run a full event on a single tank Razz
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Post Sat Feb 04, 2006 6:47 pm 
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Philip
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I think 20 oz would give about 42 litres of gas at 100 psi. You can calculate the volume of the cylinder in litres and decide how many shots you are likely to have in three minutes.

What is the stroke of your ram?

Your ideas for a huge buffer and large flow rates will give you a great flip. That is the difference between a flipper and a lifter.

Be warned: Flipper owners are tossers.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Post Sat Feb 04, 2006 7:49 pm 
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kkeerroo
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The ram is the only part of the whole robot I don't yet have. Just like most of the parts for this robot I have been looking around on the internet to buy one (ebay in this case) because pneumatic parts cost a fortune here. I have bought a 40mm bore x 75mm stroke ram off a bloke on ebay but it hasn't arrived and he's not answering my e-mails. I have now started biding on a 80mm bore x 200mm stroke ram as a spur of the moment type thing.
The smaller ram will only give me about 22kg of lifting force (my brother will not like me mixing my units of measurment) and about 225mm of movement on the end of the flipping arm. But with only 100ml of volume at full extension it will move extremely fast and I will get enough flips from a 20oz tank to keep me going for the longest of melees.
On the other hand, the larger ram will give me 117kg of lift and about 600mm of travel but at 1l in volume will be considerably slower than the smaller ram. Some experimentation is in order. I may end up using the larger ram in a future light-weight.
With 3/8" tubing and a vlave Cv of 3.8 I don't think flow rate is going to be a major issue.

P.S. with only $5 difference between a 7oz and a 20oz tank the choice seemed logical to me.
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Post Sun Feb 05, 2006 8:40 am 
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kkeerroo
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I am still waiting for the rams to arrive. The guy who I purchased the smaller one from off Ebay is not replying to my e-mails and is now no longer a registered user of Ebay for some reason. Hmmm. The larger one will arrive in a week or so.
I also went to BOC and picked up a cylinder of CO2. I am surprised at how easy it was. Just fill in the paperwork to set up an acount and hand over the money for the hire of the cylinder and purchase of the gas and away you go. No questions, no safety lecture, nothing. Too easy.
But now I have a problem. The fill station I have has a CGA 320 fitting which is a standard American fitting (American websites call it a standard international fitting. Rolling Eyes ) but the BOC cylinder has a 1/2" 14tpi BSP thread like all European and Australasia gas fittings. So now I need to go and find a new fitting for my fill station (any suggestions Phillip?).
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Post Sat Feb 11, 2006 4:15 pm 
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Philip
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I went to Peal Industrial Supplies, Unit 1/30 Moss Street, Slacks Creek, 3208 3044. The guy there spent ages going through all of his fittings and addaptors. He rang someone up for more information. After about 3/4s of an hour, he pulled a new regulator off the shelf and dimantled it and sold me the part that screws onto the bottle for less than twenty dollars. That part ended in a standard thread from which I was able to conect to a flexible hose. I always go back there after that great service.

http://robowars.org/forum/album_pic.php?pic_id=1152

There was a small insert in the regulator fitting that needed to be removed. The goal is to get liquid out of the BOC tank and into your paintball tank.

Some useful info here http://www.teamonslaught.fsnet.co.uk/co2_info.htm

The main thing to remember is not to fill more than the allowable nett weight, ie 20 oz. I normally do not fill above 75% of the maximum safe nett weight due to QLD temperatures. You might have seen me weighing the bottle before and after filling.

The American pantball sites are often very useful sources of information. They will give you safe procedures for filling CO2 bottles. The American robot sites are less helpful with information.

Let me know if you want any other info or pictures.

EDIT Let me know if you can't find the parts before HOC. You can borrow my fittings. I will be in Bris all next week at Carina about 5 mins from the Gateway arterial, if you need to get the parts.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Post Sat Feb 11, 2006 6:00 pm 
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kkeerroo
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Yes, it is just that "nut" that is the problem. It is not a standard spare part so you can't get one off the shelf. The only way I can see to get one is to buy a second hand regulator and switch the nut from the fittings.
The other option, which my brother doesn't like for some reason, is that I can by a brass adaptor from McMaster (I need to place an order with them soon anyway) that will go between the bottle and my fill station. I just need to confirm wether the CGA 320 fitting has a NPT thread.
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Post Sat Feb 11, 2006 6:47 pm 
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Philip
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You could also take the bottle to a place that makes hoses such as Pirtek (sp?). The hose that Mario sent with the ram screwed straight onto the CO2 bottle's valve.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Post Sat Feb 11, 2006 6:56 pm 
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kkeerroo
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After hours of surfing the ne I have found that a CGA 320 fitting has a .825"-14 NGO-RH-EXT thread and it is therfor unlikely that I will be able to find an adaptor. I am just going to have to replace the entire fitting.
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Post Sat Feb 11, 2006 10:56 pm 
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kkeerroo
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After giving up on the BOC website for info I went to the CIGweld website and found that the fitting I want is a AS 2473 Type 30 (.860" – 14 TPI RH Int). This is the fitting from their beverage regulator (the only one suitable for CO2) and the nut is aparently available as a spare part.
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Post Sun Feb 12, 2006 8:51 am 
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kkeerroo
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I was meaning to keep up to date with this build thread but my computer thought otherwise (The hard drive started clunking badly and the problem has now been traced to the power supply).
From the begining:
After e-mailing/calling/visitng various gas and hose fittings/fire extinguisher servicing/home brew shops I was forced to by a cheap CO2 regulator for the fill station fitting. So now last weekend I gassed the system (minus the ram) for the first time.
The 2nd ram I ordered arrived mid last week and has prompted me to do a complete rethink of the robots final shape. Here are the details of the pneumatic setup that will be used in the final robot:

supply from 20oz CO2 paintball bottle (750 psi at room temp)
regulated using a Palmers Pro Shop regulator (0 - 250psi)
either 1/4" or 3/8" polyurethane tubing (177psi max) with acetal instant tube fittings (150psi max)
shut-off/purge valve is a 3 way brass ball valve (400psi max)
gauge from a truck tyre inflator (0 - 150 psi)
buffer is a 1kg fire extinguisher with stainless steel adaptor (1200kpa max = 174psi)
Valve is a SMC 1/2" pilot assisted 3/2 solenoid valve (0.8Mpa max = 116 psi)
The ram is a Festo 200mm stroke, 80mm bore aluminium ram with 3/8" ports (180psi max)

The regulator will be set at 100 psi for the comp (only taken it up to 75psi for testing so far) so all componants are rated for the maximum working pressure as per the rules as well as having guages and manual shutoff and purge valves.
Since the ram is such a chunky thing (402mm long 100mm wide) it will now be laid down in the robot horizontaly Thermidor style (or Stealth style even though it is not my intention to copy that robot in any way). Since the ram is also of rather heavy construction it will also be a major structual element in the robot. And even tho I promised myself I wouldn't do this the chassis will now be mostly polycarb.
Construction is already well under way.
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Post Sun Feb 26, 2006 9:38 am 
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Daniel
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Post Sun Feb 26, 2006 10:20 am 
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dyrodium
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Shocked Funkyness! You should get alot of power out of that gear!
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Post Sun Feb 26, 2006 10:23 am 
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Philip
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My guestimate is that you should get about two thirds the flip of Marauder at 116psi (max psi of valve). What is the weight of the ram valve and buffer combined?

Edit; You should have the same flipping ability as Marauder if you up your pressure to the 180 psi of your ram.
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So even the rain that falls isn't actually going to fill our dams and our river systems

Post Sun Feb 26, 2006 3:33 pm 
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