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F.A.Q.s

Below you'll find a list of Frequently Asked Questions and their corresponding answers.

1) Why "The Jet Pack"?

2) In that case, what was the outcome?

3) PowerJets. Wasn't that the name of Sir Frank Whittle's company back in the 30's?

4) We need fuel. Where do we get this stuff?

5) But not all petrol stations have Kerosine. What do we do now?

6) I'm fed up with paying 8.99 for a tiny cylinder of welding gas from Halfords. They don't last and its costing me beer money. Can you help?

7) We need hydraulic fittings and couplings. But they seem so expensive. Where do we get them from?

8) Turbocharger based jet engines are the obvious starting place, but where can you get them from?

 

1) Why "The Jet Pack"?

Because that was our team name in the 2003 series of Channel 4's SCRAPHEAP CHALLENGE.

 

2) In that case, what was the outcome?

Watch it and see. We can't say. It's still too painful.

 

3) PowerJets. Wasn't that the name of Sir Frank Whittle's company back in the 30's?

Yes. Hence the name of this website. A fitting tribute we hope since he had the guts and the sheer determination to carry on when the odds were stacked against him and there was no money in the pot.

 

4) We need fuel. Where do we get this stuff?

GAS:- (LPG)

Propane (C3H8) is heavier than air and quite easy to come by in camping shops. Don't confuse it with Butane (C4H10) which is in BLUE cylinders in the UK. Propane releases approximately 25.5 kJ of energy and usually the cylinders do not have any regulators on. Butane ones do and releases slightly more energy than Propane at 28.8kJ. Propane is in the ORANGE cylinders in the UK. If you are new to this you will need a to set up a contract. This is about 40 to start and about 20 for the gas from any camping shop that stocks LPG. The cylinders remain the property of the supplier and when empty you can take it in to any dealer anywhere in the country and exchange it for a full one. 19kg cylinders are about 20 and 13kg ones are about 15.

There is a cheat you can employ. On your travels around scrapyards scavenging for bits you may see old Propane cylinders lying around. Pick them up, sling them in the back of the motor and after you've cleaned them up and checked they are ok, look at who the gas is supplied by (ie- Calor) and take it in to your nearest camping shop or petrol station.  They assume you have a contract and will just exchange the empties for the prices above. Everyone's happy.

LIQUIDS :-

Well we all know jet engines run on special aviation fuel. What makes it so special. Well basically all aviation fuel is is Kerosine (Parafin) with added rust inhibitors and water inhibitors. The higher grades are more refined. The most common is JET-A1.  Basically under altitude of an aircraft strange things tend to happen and fuel doesn't like to vapourise properly, hence the special grades. Now since you're not going up, up and awayyyyy (unless you happen to live at the top of Ben Nevis) you don't care about this side of physics...

...so use ordinary Kerosine from a petrol station.

 

5) But not all petrol stations have Kerosine. What do we do now?

Well gas turbines are like Diesel engines. They are pretty good at burning all sorts of flammable things.

We use Diesel.

We have used WD-40 in the form of 5 Litre bottles.

We've mixed Diesel with WD40. Mixed it with Jizer engine degreasant. Even with a dash of petrol to help things along.

It just means your creation may smoke a bit more than usual, or it might light up at inappropriate times. BE CAREFUL!!!

 

6) I'm fed up with paying 8.99 for a tiny cylinder of welding gas from Halfords. They don't last and its costing me beer money. Can you help?

Yes. For most MiG welding jobs Carbon Dioxide is ok (CO2).  All the gas does is prevent the welding joint from oxidising while the arc is struck.  Argon is better for welding Stainless Steel due to the better heat penetration and less carbon in the joints.  But for your uses CO2 is fine.

Now, what's got C02 in it? Fire Extinguishers!!

Find yourself a local fire company and ask them for a fire extinguisher without a nozzle on. We've got a 12kg extinguisher which cost us 10.00. Then nip down your local hire centre or welding shop and grab yourself a regulator that fits the top of the extinguisher cylinder, usually about 3/4" BSP. We had one without clocks to keep the cost down. That was 25.00.

Hook the whole thing up to your welder and there you have it.

 

7) We need hydraulic fittings and couplings. But they seem so expensive. Where do we get them from?

Ok, this is a tough one. There are some things that will cost money. But we did find a way around it. As always eBay has saved us a few times. Just look for bargains, people selling a bag of 10 BSP 1/2" to 1/4" couplings.

Having said that, not all eBay items are such bargains, and its no good when you want the goods now.

So, we went through the Yellow Pages and found some local hydraulic firms.  Go and browse a few and if you're lucky you might find one, as we did, who is more like a hardware shop. Plastic bins of shelves full of fittings and a wheezy slow chap serving. Perfect! Slap a score on the counter and ask for a selection of bits and no receipt. Keep going back there, get your face known and soon you've got a draw in the garage or workshop full of fittings.

 

8) Turbocharger based jet engines are the obvious starting place, but where can you get them from?

Yep, a home-brew turbocharger engine is a good place to start and they make a darn good noise.  Usually it's nice to work with the big truck turbochargers but they are not easy to come by, and when you do find them on eBay and the like they usually sell for hundreds.

So, easy thing is whip off a small turbo unit from a turbo diesel at the local breakers yard.  Most of these will be in pretty good nick, just getting them off a rusty old engine is the hard part. Many a scathed knuckle and swear word has been uttered while doing this. The bolts are usually pretty rusted on, so plenty of WD-40. Sometimes it's easier to take the whole exhaust manifold off.

Again the good ol' Yellow Pages comes in handy. Let your fingers do the walking. Trawl through it and look for "Commecial Vehicle Dismantlers".  These guys break trucks and vans. The nice ones will let you have a look around and might have and old unit in the scrap bin.

Check them out, usually they have FOD damage or knackered bearings. FOD (Foreign Object) Damage is no good if the compressor wheel is broken, but if it's just bearings then a service kit can usually purchased for the turbo for around 50-120 if you can identify it.  Holset units are very good and on their website (see links page) you can download all the service manuals for them.  Don't worry too much about balancing them, as you're more than likely going to blow them to bits anyway.

 

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