Jet A1 in a 100LL engine?
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Jet A1 in a 100LL engine?
Bare with me here.
It used to be the case in Scandinavia in the 60's and early 70's that Kerosene (which is Jet A1, for all intents and purposes) was cheaper than gas. So, a lot of manufacturers and retrofitters did a cheeky conversion of sort (a bit like the LPG people do today). They had the car start on gas, then once the temp had come up they switched over to Kerosene form another tank. Apparently worked really well, but did lose some slight power.
How this was achieved I'm not entirely sure, but I think the exhaust was piped around the Kerosene inlet to warm it up and vaporize it, so it could ignite easier.
Now, in these times of imminent banning of 100LL and death and doom for petrol pistons, and if this worked for old car engines, couldn't it be made to work for piston powered aircraft engines?
It used to be the case in Scandinavia in the 60's and early 70's that Kerosene (which is Jet A1, for all intents and purposes) was cheaper than gas. So, a lot of manufacturers and retrofitters did a cheeky conversion of sort (a bit like the LPG people do today). They had the car start on gas, then once the temp had come up they switched over to Kerosene form another tank. Apparently worked really well, but did lose some slight power.
How this was achieved I'm not entirely sure, but I think the exhaust was piped around the Kerosene inlet to warm it up and vaporize it, so it could ignite easier.
Now, in these times of imminent banning of 100LL and death and doom for petrol pistons, and if this worked for old car engines, couldn't it be made to work for piston powered aircraft engines?
Last edited by AdamFrisch; 10th Jun 2010 at 20:59.
Gas oil engines started on petrol, then when hot went over to gas oil. They were fitted to boats and tractors, before pure diesel engines replaced them. They were heavy for their power. Needed two fuel tanks. They were certainly used in the U.K.
For all intents and purposes Jet A is (virtually) the same as Diesel.
Avgas is virtually the same as high octane pump gas.
So no, you can't burn only Diesel in a petrol engine or the other way around.
You can run small amounts of contaminated fuel as in about 15-20% petrol in a diesel engine and vice versa.
Turbo prop and jet engines can pretty much run on anything that is combustible but it wouldn't be certified to do so and therefore un-airworthy.
The Russians used to be famous for having airplane engine that could run on the same shabby fuel as their tanks.
Great example is the Sukhoi 25 "FrogFoot".
In short, no you cannot run Diesel or Jet A in a airplane "petrol" engine
Avgas is virtually the same as high octane pump gas.
So no, you can't burn only Diesel in a petrol engine or the other way around.
You can run small amounts of contaminated fuel as in about 15-20% petrol in a diesel engine and vice versa.
Turbo prop and jet engines can pretty much run on anything that is combustible but it wouldn't be certified to do so and therefore un-airworthy.
The Russians used to be famous for having airplane engine that could run on the same shabby fuel as their tanks.
Great example is the Sukhoi 25 "FrogFoot".
In short, no you cannot run Diesel or Jet A in a airplane "petrol" engine
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I don't think an avgas engine would even run, never mind start, on avtur or diesel.
BTW I don't believe any imminent demise of avgas. There are tens of thousands of avgas planes around the world. About 1/3 of avgas burnt is burnt in engines which cannot run 96UL or similar. Some very good replacement fuel will need to be worked out, and probably retrofit fadec / electronic ignition systems will come in too, for some engines.
You can probably run an avgas engine on a mixture with maybe (at a wild guess) 10% of avtur because the stuff is bound to be soluble in avgas...??
BTW I don't believe any imminent demise of avgas. There are tens of thousands of avgas planes around the world. About 1/3 of avgas burnt is burnt in engines which cannot run 96UL or similar. Some very good replacement fuel will need to be worked out, and probably retrofit fadec / electronic ignition systems will come in too, for some engines.
You can probably run an avgas engine on a mixture with maybe (at a wild guess) 10% of avtur because the stuff is bound to be soluble in avgas...??
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As I understand it JetA1, diesel & paraffin are pretty much the same stuff & I know that a hot petrol engine will run on paraffin. Many years ago before 24hr opening a friend used to buy paraffin from a forecourt dispenser and run his Landrover on it when he couldn't get petrol. I have done the same with a lawnmower. The engine will only start if it is hot enough to vapourise the fuel. The Landy used to smell like a jet when it went by!!! I am not suggesting you try this in your aircraft!!
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Turbo prop and jet engines can pretty much run on anything that is combustible but it wouldn't be certified to do so and therefore un-airworthy.
I would not want to foot the bill for running Avgas through them though at our flow rates!!
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Turbo prop and jet engines can pretty much run on anything that is combustible but it wouldn't be certified to do so and therefore un-airworthy
BTW I don't believe any imminent demise of avgas. There are tens of thousands of avgas planes around the world. About 1/3 of avgas burnt is burnt in engines which cannot run 96UL or similar
It seems to me that we're about 50% beyond that deadline now, with only modest progress. The 2015 end date I have read about, would represent a doubling of the EPA offer. Considering how serious they seemed about this in the mid 1990's, I would not be surprized if they just banned 100LL, and said "We told you so". 100LL burners represent such a tiny fraction of the gasoline users, they do not speak with a loud enough voice to overcome the "get the lead out" movement.
I envision a big rush for replacement aviation gasoline approval in the next few years...
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In fact, unleaded avgas with an octane rating of 100 or more is not too difficult to make. Technical-grade xylene (or an unseparated mix of toluene and xylenes) would have an octane number in the 100-110 range and may even be slightly cheaper than 100LL. Unfortunately, it has a much higher inhalation toxicity and is more aggressive to elastomers than regular avgas, but this isn't an unsurmountable problem.
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Although I would be very saddened by all the aircraft that will get grounded by a 100LL ban, I do welcome the fact that if nothing else, it will pull the aircraft industry kicking and screaming into the modern world.
It's nuts that they haven't come up with engines that can run on unleaded or explored diesels. The Germans managed to certify not only one, but two diesel engines in a couple of years (the Austro in record time) and Continental and Lycoming are still scratching their a**es? Continental has now bought a french diesel, so let's see where that goes...
It's nuts that they haven't come up with engines that can run on unleaded or explored diesels. The Germans managed to certify not only one, but two diesel engines in a couple of years (the Austro in record time) and Continental and Lycoming are still scratching their a**es? Continental has now bought a french diesel, so let's see where that goes...
There is a long detailed item about the impending demise of 100LL and what can be done as alternatives in this month's AOPA UK magazine (we're all AOPA members here surely?). I don't have it with me but IIRC it's potentially less than ten years away that the US will ban it and some chap in Sweden makes a suitable subsitute but it doesn't get used outside Sweden becuase our free-market loving American cousins would stamp all over him if he tried. Of course, that may all be propaganda.
Oh, and with ten years reprocating engine design behind me, I echo the comments that putting gasoline in your compression ignition reciprocating engine or diesel (jet fuel) in your spark ignition reciprocating engine is a very bad idea indeed, whether it's an automotive or aviation application. I wouldn't think gasoline would do much good in your turbine engine either but I don't have the expertise to be sure.
Well said Adam. It's ridiculous that Cessna and Piper build new aeroplanes with electronic instrument panels, airbag seat-belts, etc. then fit the same 1950s technology engines.
Oh, and with ten years reprocating engine design behind me, I echo the comments that putting gasoline in your compression ignition reciprocating engine or diesel (jet fuel) in your spark ignition reciprocating engine is a very bad idea indeed, whether it's an automotive or aviation application. I wouldn't think gasoline would do much good in your turbine engine either but I don't have the expertise to be sure.
Well said Adam. It's ridiculous that Cessna and Piper build new aeroplanes with electronic instrument panels, airbag seat-belts, etc. then fit the same 1950s technology engines.
Last edited by JOE-FBS; 11th Jun 2010 at 12:33.
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I wouldn't think gasoline would do much good in your turbine engine either but I don't have the expertise to be sure.
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I think if you routing around using seach you can find a petrolum engineers description about the technical differences.
Basicaly from what I remember it start's by coming out of the same tap.
Then one lot gets a load of paper work started on it and batched up and the other goes off down a pipe.
Then they start adding things to it.
Presume the difference in smell's is just the different esters to do with the additives.
Basicaly from what I remember it start's by coming out of the same tap.
Then one lot gets a load of paper work started on it and batched up and the other goes off down a pipe.
Then they start adding things to it.
Presume the difference in smell's is just the different esters to do with the additives.
Often said that Jet A1 and diesel are the same stuff
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Often said that Jet A1 and diesel are the same stuff
In short they are similar, but not the same
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In a previous existence I used to work with military helicopters. To cut down on logistic chains, we would often use one type of fuel (F34 with FSII - broadly the same as JET A1) for both the turbine powered aircraft and our diesel support vehicles.
I'm not sure I would be playing with fuel types in a pathetically old school Lycoming/Continental design that should have been consigned to the scrap yard in the early 70s.
I'm not sure I would be playing with fuel types in a pathetically old school Lycoming/Continental design that should have been consigned to the scrap yard in the early 70s.
