Pneumatics for my axe

Dan Im no expert on the forces involved in an Axe weapon...but Id suggest that 250 joules is the max you might want to aim for.

Perhaps 60mm bore x 80mm stroke.

Edit :- A quote from a post by Mark Lumb.

Little Hitter uses an 80mm bore ram with 50mm stroke, and even though its only an axe its quite capable of throwing itself out of the arena at 10 bar

Work out the energy involved in the above ram.

(Message edited by woody on July 26, 2008)

Yes im understanding pneumaics alot more now.

So without getting a smaller ram,is there anyway that i can limit the power?

Thanks.

Sure ...Just use a lower pressure.

You MUST watch the total weight of all your compenents.
So before you spend loads of money on unsuitable / heavy parts make a guesstimate of the bots final weight.

(Message edited by woody on July 26, 2008)

I have a kind of guesstimate weight,about 12.5kg with all the stuff,but only 5-6mm polycarb armour.

Thick enough?

I can guess what your going to say.....lol

Thanks.

u dont need armor

i would say why

but thats my secret to winning

Care to list the pneumatic component weights Dan ?

Ram , Buffer , co2 bottle , pressure regulator , Axe and mech ,suitable 5/2 pneumatic valve ... sundry pipework and fittings.

Ultimately its your choice and if your happy go for it.:)

Ram-about 1.5kg?
Co2 bottle-500g
Buffer-1kg for both
Regulator-I dont know
Axe and mech-2.5kg
Valve-450g
Battery-400g
Motors-1kg
Speedos-150g?

Total:Around 7.5kg

So that gives me about 5-6kg for chassis and armour.

Which i am sacraficing for the Axe.

So 5mm to 7mm polycarb.

Some of my calcs might be a bit out,but thats around about right.

Thanks.

The SMC CG1 Ram you linked to further up the thread appears to weigh in at around 3.5 kgs.
http://www.smcetech.com/CC_catalogs/smc/pdf/CG1_EU.pdfhttp://www.smcetech.com/CC_catalogs/smc/pdf/CG1_EU.pdf

No im using a different ram,but that was just a geusstimate weight for it.

But even if it does weigh 3.5kg,i still should be ok.

Do you think I will need one or two buffers?

Just the one buffer tank should be fine.

Ok,Mario said i should have two,otherwise I would only get about 20 hits.

Thanks Woody.

The quantity of liquid co2 in your main tank dictates the number of available shots.

I said that the volume of the Buffertank should be 3 times the volume of the ram, or more.
Less, and youll use up more weight for less advantage.

My take on a buffer tank volume....

Twice the rams volume is acceptable ...three times the rams volume is good.... but anything is better than nothing.

Powder extinguisher bottles etc make light l.p. buffer tanks just check the pressure rating before using.

Ok,I think to start I will have only one 12oz buffer,and a 12oz main.

Is that good?Or should I have a bigger main?

12oz liquid co2 = approx 18 litres of gas @ 10bar.

A 12oz tank has a volume of around 0.5 litre.

Is it enough ....dunno.

Your ram volume is?

Im not sure what my ram volume is.

I havnt got it yet.

80 x 80 ram = 400cc

Ok,so what kind of thickness on my axe head would i need to stand up to the power?

What material do you think would be best?

Thanks.

The question has to many variables for me to really answer.
Weight , size and shape of axe head all have some bearing on the material you could use.

A piece of Hardox might fit the bill.

Where is hardox avalible from?

The shape will be like this-

http://news.terrorhurtz.com/2003/axe.jpghttp://news.terrorhurtz.com/2003/axe.jpg

But single headed.

The size is the question really.

Thanks.

Im sure you could acquire a suitable piece from someone on this Forum.

(Message edited by woody on July 28, 2008)

So do you think 5mm hardox would do?

Probably will do, might bend if it got hit by a spinner, but then your arm probably will bend also.

Thanks for the help.

Ed,what are you useing for your axe?

Only a bit of 10mm thick titanium I had lying around.

I like how you said only lol.

Any spare?lol.

Even a chunk of alu will do. Unless you hope to achieve some cutting action.

Yeah,cutting is the one thing i dont want.

I dont want my axe to get stuck in the other bot.

I think i will use hardox,is it heavy?

Hardox has the same weight as steel, as it is a low alloy hi strength steel. 7.85kg/dm³

Thanks Mario.

Is it expensive to get hardox cut?

You can cut it with an angle grinder, so not really unless you want complex shapes. I made an axe head for Mayhem from hardox with nothing more than a grinder. Drilling can be hardwork, sharp drills are vital, once they are slightly blunt they need to be resharpened before using again. You can get away with it a bit more on ali but there is no chance with hardox. There are quite a few laser cutting places about these days, but they will be fairly expensive for one offs.

the axe head on mayhem is 4mm hardox and that was bent by hornet 2 so if you want something realy strong you would have to go thicker

Tut, these kids never look after the things you make for them. Matt do you need a new one or need it straightening? Ive still got the template.

Lol,yeah my axe head is quite a complex shape (same as THz) so maybe laser cutting is best.

I got a mate with a plasma cutter maybe he would do it....

Still havnt got a suitible axe arm,any suggestions on something thats easy to find?

ti bar or thick ali bar might do depending on what grade ali you use
ed its ok still fits in the arm lol big chunk out of it though:sad:

Ok,will I need one of these for my buffer as well as my main tank?

http://www.shop.justpaintball.co.uk/acatalog/Co2_On___Off_Valve.htmlhttp://www.shop.justpaintball.co.uk/...Off_Valve.html

And does this need to be accessible like a link is?

Thanks.

No.
You will however need a dump valve of some sort connected to the buffer.

Ok,thankyou Woody.