air tank help

[DAVE JOHNSON]

I am in need of some empty gas aerosols/Tamar canisters etc to make up several airtanks for my Vulcan----has anyone got any large ones kicking around?? or any other suggestions what can be used for this job? they are not exactly holding me up yet,but will be in near future,so anyone who has any spare could pick up at Gaydon !!!

Also---my retracts have 4mm pipe and fittings because of the size of cylinders,so aa normal retract valve will not allow enough air thro ,so looking at a commercial valve or similar---has anyone had any experience of these or could recommend one??

Ted Allison has now fitted one in his 1/3 Lightning,so we may get to test that soon if the weather holds,but any help would be appreciated

[Andy Boylett]

coke bottles take 80psi before bending.....

http://www.instructables.com/answers/how-much-psi-does-a-coke-bottle2l-hold/

[DAVE JOHNSON]

Thanks Andy---i had considered pop bottles,i have them in several existing models,but not sure as yet what pressure these will need to run on---i expect much more than that as they have to lift 8 wheels on each leg---this is why i am looking at cans---i have found 3 now which i have soldered brass pipe into,and fitted festos to pipe all together for one big tank----this will do one wing ---i now need enough for the other wing and the fuz for the noseleg--DAVE

[John Greenfield]

Dave

I have been using "commercial" valves and 4mm tubing in my big models since the Lancaster days as model size valves just cant pass the volume of air needed for big retracts. The set up Ted put in his Lightening is as used in my models. If you want details of the suppliers give me a call any evening and I will give you the details and part numbers.

John

01923 857009

[DAVE JOHNSON]

John--thanks for that---Ted has passed me the details of the Valve you recommended--he is sending me a photo of the valve size/installation today,but just wondered what else similar was out there---as a matter of interest,what type and size of air tanks did you use ??DAVE

[Phil Clark]

Dave

Here's the valve I used on the B-26, sourced via 'Wearside Pneumatics'. This used 4mm Festo tubing and was driving 25mm bore, 250mm stroke rams on the main gear with ease. It was a 'press button' type actuation and it was quite heavily spring loaded, hence the need for the large servo operated lever to press it.

Air tank wise, I had Alan Cantwell make me us this 4 ltr carbon fibre/aluminium tank (end caps were Hysol bonded with a threaded tie bar attaching the 2 caps together through the middle). I pressure tested it several times for several hours up to 120psi before fitting with no issues. It's been in the model over a year now and having made 20-30 flights, it's still prefectly OK

I'd steer well clear of pop bottle as they may take the pressure, but they are not intended for repeated pressurisation......anyone remember the yellow Texan at Cosford in the mid 90's that has a pop bottle tank blow in the pits......messy

Phil

[Barrie King]

Dave, I have a couple of empty Aluminium Arcton 12 canisters they are 10inch long and 3inch diameter and only weigh 120g each, just look like big aerosols, thread on top is 1/4 SAE, they are yours if you want them, can bring to Gaydon.

Cheers,
Barrie

[DAVE JOHNSON]

Barrie--yes please,will take them off you .Phil---do you have a part number for the valve and price?--DAVE

[Alan Cantwell 1131]

Dave, i have today, asked the gaffer of trycast, our carbon supplier, for any redundant tube, stay tuned, with a simple pair of simple end caps, as in Phils piccy, it makes a hell of a res, and weighs not a lot

[Alan Cantwell 1131]

double post, oops

[DAVE JOHNSON]

Okay Alan--the only problem is i am installing 3 seperate systems in the Vulcan,i dont want pipes trialing around the airframe so each leg will have its own system---so i need 3 tank set ups !!!!!

[Alan Cantwell 1131]

Gawd, dont do things by halves, do you? lets see if he can come up with something, Phils one was destined to be a ballast tank for a mini sub, looks pretty, doesnt it?

sorry about the double post above, NO idea what happened there!!

[Phil Clark]

Dave

Sorry, no part number other than what is printed on the valve body (see below), it was bought 4-5 yrs ago well before the model was finished. Price was only about £ 40 IIRC though (only real down side is this one was very heavy as it was of mainly steel construction)

Phil

[DAVE JOHNSON]

OK Phil---thanks for that info---Ted has sent me a piccy of his in the Lightning,and it looks similar--with part number and supplier---will need to chase up and try--DAVE

[John Greenfield]

Dave

In my models I use spent Gas canisters from turbine starting Also used for bolw torches. Taymar are the ones I used about 11" long and 3" dia. It is easy to drill out the plastic seal in the top and solder in a 4 mm nipple to take the festo tubing. Very light and strong. I just ganged them up to get the required volume.

Call if you need more info on the valve as I dug the invoice out last night for you with the part numbers and company contact details.

John

[DAVE JOHNSON]

OK John---thats great,will buzz you--DAVE

[Mike altham]

Hi,

I am having the same problem for the Nimrod.

What are the valves you are using as mine are all 4mm festo fittings as well?

Cheers,

Mike.

[DAVE JOHNSON]

Mike--you should be able to see my set up at Gaydon--DAVE

[Mike altham]

Hi Dave

Ok will have a nosey at it. Thinking doing same as you with a separate system for the nose leg to save any air disconnects and possible leaks.

Mike

[Mike altham]

Hi,

Found some 1 litre airtamks that have 4 mm festo barb fitting brazed into them. The only thing is they cost a lot. (Hawe modelltechnik)

How do you make a gas canister into one?

Could you use the ones that have the threaded inserts in like the ones used for gas regulators when starting a turbines?

Cheers,

Mike.