Siphoning fuel from a small airplane

JayMan · Oct 27, 2011

My characters find themselves at a small, public airport--two short runways and a couple recreational, piston-engine planes (say, Cessna 172s or 152s, though this can be altered as the story requires).

If they want to siphon the avgas from these airplanes, what would be the best way to go about it? Would it be as simple as opening the overwing gas caps and siphoning it out? A related question: do small airports carry siphoning equipment, or would the characters have to obtain tubing, and if so, what appropriate tubing could they cannibalize from the plane itself to use in siphoning?

Or would it be more practical to slowly drain gas from the underwing fuel sumps?

Noah Body · Oct 27, 2011

I'd use the sumps. Especially if they have to be furtive about it...seeing a couple of guys on step ladders pulling fuel out of the tanks might arouse suspicion.

Any reason why they can't just use the fuel truck to get some fuel?

JayMan · Oct 27, 2011

Thanks for the response Noah Body.

The story takes place in a post-apocalyptic setting, and there's nobody to hide from, so they need not be furtive!

For the story's sake, let's say there is no fuel truck present.

Noah Body · Oct 27, 2011

Oh, then they can just suck the 100LL right out of the tanks. Would be faster than using the sumps.

jclarkdawe · Oct 27, 2011

I don't know how fast avgas goes funky, but having just read a post-apocalyptic novel where the protagonist, fifteen or more years after the apocalyptic event, is able to use regular gas for a car, I have a concern for you.

Problem is some of the compounds in gas break down in months, and after less than a couple of years, gas is no longer usable. When I was on the fire department, we'd throw out the gas in the chainsaws and things like that every three months. And no one wanted to add it to their cars. And this is with stabilizers added.

So how long does avgas hold up? Because a gummed up engine at 2,000 feet is probably not a fun experience.

Best of luck,

Jim Clark-Dawe

JayMan · Oct 27, 2011

Thanks again Noah, that simplifies things for my purposes.

And that's an interesting point Jim. My story takes place only six months after the event. Also, none of the characters knows how to fly; they're taking the gas for use in an SUV. If my research is correct, this will eventually foul up the catalytic converter, but they're only looking for a short term solution to avoid having to walk for the time being.

jclarkdawe · Oct 27, 2011

JayMan said:
Thanks again Noah, that simplifies things for my purposes.

And that's an interesting point Jim. My story takes place only six months after the event. Also, none of the characters knows how to fly; they're taking the gas for use in an SUV. If my research is correct, this will eventually foul up the catalytic converter, but they're only looking for a short term solution to avoid having to walk for the time being.

I'd buy that.

Best of luck,

Jim Clark-Dawe

JonathanBenway · Oct 31, 2011

100LL would have a shelf life of at least a year, maybe two.

It would screw up the catalytic converter on a car designed for unleaded, but the big problem would be that it'd foul up the O2 sensor. The car's ECU would think it's running rich and lean out the mixture. You can ruin an O2 sensor in as little as a few hours on leaded fuel.

Kenn · Oct 31, 2011

jclarkdawe said:
Problem is some of the compounds in gas break down in months, and after less than a couple of years, gas is no longer usable.

It really depends how it is stored. If there is little airspace above the fuel (i.e. a full tank) and no moisture in it, then it can last for ages.

jclarkdawe said:
When I was on the fire department, we'd throw out the gas in the chainsaws and things like that every three months.

It was probably a two-stroke mix which has a much shorter shelf-life than petrol.

An alternative might be to consider a diesel-engined vehicle and to top it up with jet fuel.

Siphoning fuel from a small airplane

JayMan

Like Burt Reynolds in Gator

Noah Body

Entertainment Ronin

JayMan

Like Burt Reynolds in Gator

Noah Body

Entertainment Ronin

jclarkdawe

Feeling lucky, Query?

JayMan

Like Burt Reynolds in Gator

jclarkdawe

Feeling lucky, Query?

JonathanBenway

Kenn

New kid, be gentle!