dockmaster
Well-Known Member
Hi has anyone had issues with the increasing amount of ethanol in unleaded fuel damaging plastic tanks, aparently the aviation industry is up in arms at the moment with scare stories of holes being eaten in fuel tanks??
Ethanol in unleaded petrol eating plastic fuel tanks?
- Thread starter dockmaster
- Start date
duncanmack
Well-Known Member
But the aviators are not supposed to be using Bioethanol petrol, due to other safety issues.
It ate the float on my Velocette Venom.
It ate the float on my Velocette Venom.
dockmaster
Well-Known Member
Tell me more? Most microlights etc are using unleaded from the garage forecourt and marine type outboard tanks.
duncanmack
Well-Known Member
OK, my interest is in Bioethanol petrol (Mogas) - I sell it and have had problems with storing it - I won't bore you with the sorry tale.
What is relevant was that most of the "forecourt maintenance" companies weren't up to speed on potential problems and I had to research the net to fight two of my suppliers to reimburse me for two tanks of "crap" that they had supplied.
The problem is that if there is more than 40ppm of water in the unleaded than it is almost certain to "phase seperate" ie the bioethanol seperates from the petrol (you also get a lot of gunge). If it happens in your fuel tank then your engine stops.
I noticed in my reading that "mogas" was prohibited for use in aircraft. I didn't pursue the why as, although I was curious, I didn't have time due to the disaster I had on my hands.
Having just had a quick "google" I see that microlights have generally been excepted from the prohibition of using "mogas" - presumably because they a) don't fly very high and b) tend not to fly in bad weather - though I stand to be corrected on that.
Have a look here...
http://www.caa.co.uk/docs/33/201210...Unleaded Aviation Gasoline (Avgas) UL91_3.pdf
and follow it around.
ps another interest is in old vehicles and some of the other vintage enthusiasts are having problems this the fuel eating seals, gaskets, tank linings etc,
Incidentally, a load of brand-new Chinese m/cycles and scooters are causing chaos by not being Bioethanol proof. The plastics/synthetic rubbers they use in the fuel system have a tendency to dissolve and choke the filters, as does the lining with which they coat the inside of the fuel tank to seal it.... Of course the Chinese don't have Bioethanol petrol so it isn't a problem in third-world countries....
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Avocet
Well-Known Member
Yes, it's been a problem for the whole auto industry. They'll soon (in Europe at least) have to declare whether or not their older models are compatible with B10 (10% bioethanol). I think some classic car websites (like Frost) are already selling additives to counter it's tendency to absorb water.
rivonia
Well-Known Member
Hmm and heres me thinking that AIROPLANES use AVGAS which is totaly different to road fuel. OR am I wrong?
Peter
Peter
vyv_cox
Well-Known Member
Piston engined aircraft run on gasoline. Turbine (jet) driven run on Avgas.
FWB
N/A
Er, no!
Avgas for light aircraft, Jet A1 for Airliners. If anyone had tried to put Avgas in me 777 I would have been very annoyed!
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macd
Well-Known Member
Sorry, Vyv, but that's wrong. Most piston-engined aircraft (and some of the bikes I used to race) run on Avgas, which is high octane petrol. Jets run on kerosene, sometimes known as Avjet.
vyv_cox
Well-Known Member
My mistake, apologies. The clue is in the name, I suppose.
padge
Well-Known Member
AVGAS 100LL £1.98/L roughly equivalent to old style 5* petrol
UL91 £1.90/L unleaded Avgas for fussy engines
Mogas £1.40/L normal road petrol out of forecourt pumps I use this in a modern rotax 912 engine
Jet A1 (parrafin/diesel) £1/L
The main problem is most light aircraft are running 1940's lycoming style engines and the cost of getting type approval for fitting a modern engine is prohibitive .
rustybarge
Well-Known Member
Aeroplanes use Avgas for just one reason.......they are high compression engines and can only burn 100LL, or they would suffer from pinking ( predetonation) that would burn holes in the pistons, in effect just like high comp. race engines.
Why are they high compression engines? So that they can fly above 13000' where the air gets thinner, and high compression engines have a higher power output Than low compression engines giving a better power/ weight ratio.
,
macd
Well-Known Member
Rustybarge (and apologies to others for thread drift): the connection between octane ratings and piston-engined aircraft may be more fundamental than you suppose. During WW1 the Air Ministry became concerned that many of our aircraft were dropping unaccountably out of the sky. Harry Ricardo, then head of engine research at the Dept of Military Aeronautics, identified the cause as pre-ignition. He went on to develop a variable-compression research engine, which led in turn to his developing what we now know as the octane rating system,and through that fuel additives which increased octane ratings. Ricardo went on to become one of the giants of internal combustion engine development.
Next time you don't hole a piston, thank Harry.
Next time you don't hole a piston, thank Harry.
rustybarge
Well-Known Member
Hi Mac,
When I was learning to fly the instructor would not let us lean the engines in flight , letting us run at full rich and burning gals more fuel at his expense. Has the same result as low octane in an aero engine......overheated engine and burn pistons.
padge
Well-Known Member
That's because fuel is wasted in cooling the engine .A more efficient modern engine running avgas doesn't get hot enough to burn off the lead, using avgas can gum up the engine .
The fuel/compression argument doesn't hold water either
Lycoming 260 running on Avgas - Compression ratio: 8.7:1; Power-to-weight ratio: 0.68 hp/lb
Rotax 912 running on Mogas - Compression ratio 10.5 :1 Power-to-weight ratio: 0.80 hp/lb
I agree with the altitude bit but above 13000' ft I'll be needing oxygen more than the engine. In fact I've been much higher than this without an engine . It was a bit nippy though
A fuel injected engine could automatically adjust for altittude but almost all Modern pressurised aircraft are now turbine/jet powered running on jet A1.
rustybarge
Well-Known Member
That's because fuel is wasted in cooling the engine .A more efficient modern engine running avgas doesn't get hot enough to burn off the lead, using avgas can gum up the engine .
The fuel/compression argument doesn't hold water either
Lycoming 260 running on Avgas - Compression ratio: 8.7:1; Power-to-weight ratio: 0.68 hp/lb
Rotax 912 running on Mogas - Compression ratio 10.5 :1 Power-to-weight ratio: 0.80 hp/lb
I agree with the altitude bit but above 13000' ft I'll be needing oxygen more than the engine. In fact I've been much higher than this without an engine . It was a bit nippy though
A fuel injected engine could automatically adjust for altittude but almost all Modern pressurised aircraft are now turbine/jet powered running on jet A1.
Hi padge,
You're comparing apples with oranges.
Iirc rotax has a high revs continuous cruise 5000 revs(?), time between rebuilds of 500 hours, made from alloy.
The lycoming revs at 2500 revs, 2000 hrs tbo, cast block and cylinders.
IMO you're comparing a high reving Ferrari ( rotax), with a tractor ( lycoming).
Ariadne
Well-Known Member
Can we go back to the OP and stop talking about Avgas and airplanes! If that's what you want to do then take it pms, and not clog a potential useful thread about plastic tanks and ethanol fuels.
FFS, this is a boating site and I want to know how it affects my dinghy, fuel tank, etc not about planes flying!
Rant over.
FFS, this is a boating site and I want to know how it affects my dinghy, fuel tank, etc not about planes flying!
Rant over.
rustybarge
Well-Known Member
Calm down dearie! ( was that red Ed or call me Dave? )
gordmac
Well-Known Member
High alcohol fuel may damage much more modern cars than vintage, my 1993 car won't tolerate it apparently. I think I would stay clear of it unless your manufacturer of all the stuff it will come in contact with says it is ok. As far as I am aware the petrol pump will have to have a sign on it giving the alcohol content if it is more than now. Super unleaded should be ok too.
Avocet
Well-Known Member
As I understand it, quite a few European pre-1990 cars can't handle it. Some of the seals and hoses are a problem. To a lesser extent, the water that the ethanol can attract is a problem too (more so in classic cars that don't get through their tanks of fuel quickly and have it standig in the tank for long periods.
I know some classic car buffs that swear by this stuff:
http://www.frost.co.uk/ethomix-additive.html