Pneumatic Shift Systems

[ttjpc]

Afternoon all,

We are developing a pneumatic paddle shift system on this year car, which seems to do the job, but are having issues refilling the air bottles.

How do other teams running pneumatic shifts recharge their bottles? and also what sort of capacity/pressures are they? We've got some paintball gear which we're adapting and seems to be the way to go.

Thanks in advance

[Nicky]

Most teams I know have paintball canisters which they refill with scuba tanks. The pressure is pretty much standard i.e. 3000psi or 4500psi. They are filled with either CO2 or HPA.

Our canister is filled to 7.5bar and regulator steps it much lower. We didn't have the moolah to buy expensive canisters and don't have provisions here to fill our tanks. We use a small onboard compressor that charges it upto 140psi. It is simple to mount on and hardly takes any current. Plus it is 1.2kgs. I'd say worth the addition of weight for our cause(less cash+easy refilling+locally available parts).

hope that helps.

[ESaenz]

Our team went the CO2 route and purchased 4-5 9oz bottles. We are able to fill these bottles at any paintball store. Also get yourself extra o-rings and sturdy caps for the bottles when they are not use to protect the threads.
Elio

[M.dheeraj]

hi guys........thanks for the info

[nowhere fast]

Originally posted by Nicky:
We use a small onboard compressor that charges it upto 140psi. It is simple to mount on and hardly takes any current. Plus it is 1.2kgs. I'd say worth the addition of weight for our cause(less cash+easy refilling+locally available parts).

That may be so when comparing to a typical pneumatic shifter, but I'm interested to hear how you justify the added weight and complexity over a mechanical shifter.

[ttjpc]

Thanks everyone for the replies.

Originally posted by Nicky:
We use a small onboard compressor that charges it upto 140psi.
Ye, the on-board compressor idea is an interesting one, which i like, but means more components to package which is already a bit of a headache for us.

Originally posted by ESaenz:
Our team went the C02 route and purchased 4-5 9oz bottles.
How long can you get a 9oz bottle last? at around 1800psi I presume?

[Fahad Muhammad]

If I am not wrong, You should get 125 plus shifts per ounce of liquid CO2.

[SamB]

Originally posted by Fahad Muhammad:
If I am not wrong, You should get 125 plus shifts per ounce of liquid CO2.

Only whilst you still have liquid in the bottle - then you know that the pressure has not dropped. Once All your liquid has ran out you will have just gas and the pressure will slowly drop off until it hits the system pressure. Likelihood is it will stop shifting at some point, so don't be too specific with your calcs http://fsae.com/groupee_common/emoticons/icon_smile.gif

Josh,

If your system can run on CO2 I'd definately suggest switching - refilling is so much easier. We get ours refilled at a paintball shop near Old Trafford (little far for you guys, yes) but take a look for a nearby paintball outlets - they refill them quite cheaply even if the people there are a little...odd. Think its costs us about £1 each time.

Sam

[ttjpc]

We've got one of the stirrup pumps for recharging air guns so going to stick with air i think - i can see your point but saves us buying all the CO2 refilling station gear, or enough bottles to last an event with.

We're basing the air volumes on testing rather than calculations as it is so dependant on which cylinders are used etc

[Luniz]

We used to run gas bottles from a soda maker. Very convenient as they can be bought at more or less every supermarket. Drawback: Those cylinders are a bit on the heavy side.

[Nicky]

Originally posted by Luniz:
We used to run gas bottles from a soda maker. Very convenient as they can be bought at more or less every supermarket

Don't mind me asking. What kind of adapter did you use to fix your lines to the bottles? Also, did you get that certified??

[Luniz]

We found a pressure reducing valve with the correct thread in a hardware store. What do you mean by certified? We used this system 2006-2009, everything went through scruitineering.

[Nicky]

Rule book B13.1 (b): Cylinder Certification- The gas cylinder/tank must be of proprietary manufacture, designed and
built for the pressure being used, certified by an accredited testing laboratory in the country of
its origin, and labeled or stamped appropriately

That way we have an empty fire-extinguisher can for which we have an adapter already made. The bottle is certified and stamped for 25 Bar(we go upto only 8.5Bar), but our team-mates said that a proper certification was in order since we had our own adapter for it. It's real light and weighs a little over 90gms(volume: 1.1 ltr).

We dropped the idea as we didn't want to do a pressure certification test.

[Luniz]

You must have gotten me wrong on that... We have been using a CO2 cylinder used in soda makers such as "sodastream", they are certified for 300bar.

[TAFC1163]

Hi Guys.

I run a CO2 Air shifter in my Funny Car. I use a CO2 fire extigisher that i made an attachment for to refill the bottles. I can get through an event without having to refill my 9 oz bottle. This bottle controls all my fuel and ignition timers and shifter.

A cheap alternative in countrys which are not so keen on selling scuba tank bottles to the average joe.