Fuel Tank testing

I wasn’t suggesting doing it unsupported ! I am thinking of testing the Tornado fuel tank system for leaks -the Harrier forward and centre tanks and the Apache front and rear fuel cells.

^^^ You really are barking up the wrong tree doing that son! Filling a tank up without out any support with several hundred litres of kerosene will damage it. Inflating an empty tank with enough air pressure to partially inflate a party balloon will not.
You must be thinking of hydrostatic testing of high pressure bottles where, yes, to prevent explosive failures, they are filled with liquid before pressure testing.

I prefer filling to something like 80% full with Avtur and then add a little pressure to make it seep out . That way if a seam desides to let go its only got a small amount of compressed air in it when it goes!

Mike, you’ll probably find that, even with 1psi that you will have a ‘football’ of a tank. I wouldn’t take it above that anyway as that will be enough pressure to highlight any leak, you don’t want to damage it. If there is internal ribbing or stiffening or cording then this will easily be ripped out by overpressurising. 10psi is way too much.

Use an approved leak-detector fluid or, if you use washing up liquid make sure it is rinsed off thoroughly afterwards as it contains a lot of salt whereas the ‘approved’ ones do not.

Anon.

Hi Firebex,
Interesting looking lump of tank. I’d go along with most of what has been mentioned by members here, but particularly using the “Balloon” idea, (notice in Terry P’s Diagrams for flexible tanks pressurize to 0.1/4 psi ) No doubt, you will be looking at the float valve -Pump,etc too. One thing that is always used when trying to stop leaks in Fuel tanks is:- P.R.C. A gluey red oxide looking morass you mix up and apply in large dollops to any leaking area’s. It’s good ,smelly, effective stuff too. I cannot though for the life of me remember what company produced this, but someone in here will know. Best of luck with Vamp project, bet you find inside of tank is pristine.

Bill T.

Venom Fuel tank

Just in case it helps, here are pages from the Venom Volume 6:-

Thanks for all the suggestions and leads guys greatly appreciated as always,and we knew the answers would be out there.

As previous the main reason is we are going to ground run our lady and hopefully she will move up and down a runway under her own steam.We don’t currently have the budget available to do anything else with her.Although we now have all her paperwork and 700’s etc from the day she left the factory until the day she arrived at Duxford and with only 1,247 hrs and 20 minutes out of an airframe life of 3000 hrs she has a lot of potential.You never know one day we may be able to take the big step to put her back into the air so we are being very carefull and cautious with everything we do.She ha sbeen completely fabric stripped as the bolts had not been treated when she had been recovered and had rusted and caused the fabric to balloon.the wood work is in excellent condition and we have managed to obtain a lot of new spares to support her operation at present its a matter of some of the hoses,spare main wheels and tyres and brake components such as air bags and ignitor plugs we need most of all if anyone knows to any that would be most helpfull.

If anyone lives in North Yorkshire and would like to come on board with the volunteer team putting her back live you will be most welcome.we already have an ex RAF sooty and a pilot who flew vampires and in particular flew for a short time the vintage pair one (not during the mid air crash season).

Currently our engine (believed zero hour and never fitted to an airframe )has been scoped and checked and has had all new hoses fitted and is almost ready for a dry run the next step after that being a wet test (not until its back into the airframe)

Any more info welcomed

Mike E

www.aircraftrestorationgroup.org

XG743 restoration project

The simplest and safest way to pressure test your tank is to hook up the shop air via a regulator and shut off valve to the fuel outlet and to tape a party balloon to the tank vent. All other openings are to be sealed. Allow shop air into the tank until the balloon is inflated to no more than normal size and the shut off the air. The couple of PSI it takes to inflate the balloon is more than enough to enable leak checking via the previously suggested soapy water mixture applied to seams, fitting, etc, without running the risk of damaging the tank by over pressure. I do know of one fellow who managed to turn a Piper Cherokee wing leading edge tank into a football by applying straight, unregulated, shop air to it…. 🙂

You shouldn’t need more than 10 psi or so in a fuel tank to prove it.

Any failure at that pressure wont be too dramatic.

Safety in Pressure Testing

Try reading http://www.hse.gov.uk/pubns/gs4.pdf from HSE.

This is sound advice. Concentrate on assuming your pressure vessel will fail and provide safe testing containment, especially if doing testing pneumatically.

WX862

Mike,

There’s also this company in Christchurch, Dorset http://www.tankdevils.com they may now have a new name, but the link works.

As per the last two posts, plus a mixture of soapy water applied to seams / joints with a paint brush…watch for the bubbles!

Fuel tanks are pressure tested. They are pumped up to a given pressure and then left for a set amount of time. The pressure drop is then measured and if within limits you can be pretty sure it is fuel tight

Make up some blanking plates one with a valve in it and one with a gauge and bolt them on sealing them with fuel sealant, add some air pressure shouldn’t need much and watch the gauge for drop off.
That’s how I did the A4 bladder tank.

Mike Pannell

Fuel tanks are pressure tested. They are pumped up to a given pressure and then left for a set amount of time. The pressure drop is then measured and if within limits you can be pretty sure it is fuel tight

FPT are the 3rd line overhaul facility for lynx fuel tank bags so they would be a good place to start i think.

Mike
FPT, now part of GKN, of Portsmouth are able to repair and manufacture flexible fuel tanks, I think they are doing the one for the Vulcan.

http://www.gkn.com/aerospace/products-and-capabilities/flexible-protection-systems/Pages/default.aspx

Richard