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Old 06-09-2012, 02:32 PM   #1
40 Deluxe
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Default Use of avgas?

A thread on the Model A forum got me to researching this topic of avgas. There's a lot of differing opinions on what it is, what it does, etc. Here's your daily dose of tech info (several pages worth, but easy to read):

http://royalpacificpetro.com/html/te...as_content.htm

Enjoy!
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Old 06-09-2012, 02:53 PM   #2
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Default Re: Use of avgas?

Back in the sixtys while in the service, we used to use avgas to fill our Zippo lighters. Worked quite well. In the barracks you could tell who had a Zippo by the burn spots on their leg. The lighters were usually overfilled and would leak.

Last edited by sonny; 06-09-2012 at 03:14 PM. Reason: error
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Old 06-09-2012, 03:32 PM   #3
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Default Re: Use of avgas?

The most readily available AVGAS is 100LL (LL = Low Lead). Don't let the LL fool you it just means that there is a controlled amount of tetraethyl lead content. This fuel is the best quality fuel in the gasolene family that is available today. It is very stable. I've run the stuff in motorcycles after it has set in a tank for several years and it still functions normally as a motor fuel.

The big problem is cost and availability. It ain't cheep and you have to find an airport with fuel sales to buy the stuff unless you have a large containment tank and can afford to have a 3000 gallon load delivered to you from a bulk dealer. You might be able to split a 1500 gallon load with some aviation buff but they don't like to sell at much less than a tanker full.

I would guess that Sonny was using JP-4 jet fuel for a Zippo. I'm not brave enough to put high test gasolene in a Zippo. It might blow your hand off. JP-4 or Jet A would work well though. Military JP-4 is mostly unleaded benzene/gasolene with a 20% amount of kerosene and Jet A is mostly kerosene with 20% amount of unleaded benzene/gasolene or somewhere there abouts. You can run Jet A in a diesel truck with no ill effects.

Last edited by rotorwrench; 06-09-2012 at 03:41 PM.
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Old 06-09-2012, 03:52 PM   #4
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Default Re: Use of avgas?

No, for awhile I worked in the fuel pits where we would load jp-4 and jp-5 on the jets. the guys that fueled the recips. would let us fill our lighters with avgas. Can't remember the diff. between jp4 and jp5.
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Old 06-09-2012, 04:06 PM   #5
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Default Re: Use of avgas?

Isnt there a hefty fine for filling a car with Av gas? No motor fuel tax for the highways?
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Old 06-09-2012, 04:18 PM   #6
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Default Re: Use of avgas?

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Quote:
Originally Posted by rotorwrench View Post
The most readily available AVGAS is 100LL (LL = Low Lead). Don't let the LL fool you it just means that there is a controlled amount of tetraethyl lead content. This fuel is the best quality fuel in the gasolene family that is available today. It is very stable. I've run the stuff in motorcycles after it has set in a tank for several years and it still functions normally as a motor fuel.

The big problem is cost and availability. It ain't cheep and you have to find an airport with fuel sales to buy the stuff unless you have a large containment tank and can afford to have a 3000 gallon load delivered to you from a bulk dealer. You might be able to split a 1500 gallon load with some aviation buff but they don't like to sell at much less than a tanker full.

I would guess that Sonny was using JP-4 jet fuel for a Zippo. I'm not brave enough to put high test gasolene in a Zippo. It might blow your hand off. JP-4 or Jet A would work well though. Military JP-4 is mostly unleaded benzene/gasolene with a 20% amount of kerosene and Jet A is mostly kerosene with 20% amount of unleaded benzene/gasolene or somewhere there abouts. You can run Jet A in a diesel truck with no ill effects.
JP4 is a gasoline based jet fuel for high altitude spy planes. It's main claim to fame is that it won't freeze at a very high altitude. I remember it (faulty memory perhaps) being 80% low octane(like 60 octane) gasoline and 20% kerosene (was it 60% gasoline/40% kerosene?) at the refinery I retired from quit making it 20+ years ago. JP-5 is military jet fuel. The main difference between it and Jet A is the flash point is higher for JP-5 for more safety in crashes. Jet A and JP5 at the refinery I worked for was 100% kerosene.

The old high lead avgas was basically iso-octane alkylate with 5% butane added to pressure it up. BTW 100 octane is defined as 100% iso-octane. High lead avgas would work just fine in automobiles as the octane is higher than 100 due to the lead. The low lead avgas should be just fine as well.

However contrary to popular belief, high octane does not correspond to high energy content or more "power." A higher octane gasoline is more resistant to knocking so a higher compression ratio or more advanced timing can be run. Octane ratings for avgas have little relevance for cars as the test procedure is different and it is tested on an airplane engine with a lean/rich rating.

Last edited by mrtexas; 06-09-2012 at 04:23 PM.
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Old 06-20-2012, 01:10 PM   #7
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Default Re: Use of avgas?

Hi,
while i was stationed at hanscom a.f.b. We worked on the development of a jet fuel that would,nt leave contrails. I don,t know how successful they were, but as i remember it was called j-p 5.

Al
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Old 06-20-2012, 01:20 PM   #8
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Default Re: Use of avgas?

"The most readily available AVGAS is 100LL (LL = Low Lead). Don't let the LL fool you it just means that there is a controlled amount of tetraethyl lead content. This fuel is the best quality fuel in the gasolene family that is available today. It is very stable. I've run the stuff in motorcycles after it has set in a tank for several years and it still functions normally as a motor fuel."

This used to be true. Since a few years ago almost 100% of gasoline is hydrotreated. Hydrotreating removes the unstable compounds that form gums and color the gasoline. Remember when gasoline used to be yellowish or greenish(from the unstable thermally and catalytically cracked components)? Not anymore, all gasoline is "white gas". It is hydrotreated to reduce the sulfur level to a very low level, like 20ppm.
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Old 06-20-2012, 02:42 PM   #9
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Default Re: Use of avgas?

100LL is pretty much clear before they add the blue dye. 100/130 has not been available for a long time (green dye) and the 80/87 (red dye) is only available in a few places now days. There are some STCs (supplemental type certificates) that allow auto or Mogas use in certain aircraft engines per the instructions in the STCs but the aircraft engine manufacturer's won't approve it. It's generally for engines with 8.0:1 compression ratios or lower. FAA/DOT regs & Mil-Specs/ASTMs still prevent use of any alcohol (more specifically ethanol) in avgas thank god.

JP-5 is Navy fuel developed for aircraft carrier duty. It has a higher flashpoint than JP-4. The JP-4 is used by land based forces most notably the US Army for Helicopter fuel. The US Air Force is trying to switch over to a semi synthetic jet fuel called FT. There were special fuels for the XB-70 and SR-71 but both are now out of service with the ill fated XB-70 never making it to service. If they are still flying the U-2, it has a special blend for high altitude.

All US based civillian jets use Jet A. Jet A-1 is a foreign blend and Jet B is for extreme cold weather use to prevent jellation.

Last edited by rotorwrench; 06-20-2012 at 04:01 PM.
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Old 06-20-2012, 05:58 PM   #10
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Default Re: Use of avgas?

"The JP-4 is used by land based forces most notably the US Army for Helicopter fuel."

Are you sure? I thought JP4 was high altitude gasoline based jet fuel for spy planes.
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Old 06-20-2012, 07:01 PM   #11
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Default Re: Use of avgas?

JPTS is the high altitude fuel used in the U-2 aircraft. It's likely a rarity now (TS = thermally stable). When the air force was still using the U-2 hot & heavy, this fuel was only blended by two refineries in the whole world and it cost about 3-times more than JP-8 that the US Air Force used for there normal flight operations. JP-8 is a lot like the civilian Jet A-1.

When I was in the army, all we ever carried in the tankers for refueling helicopters was JP-4 and as far as I know it's still in use by the US Army.
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Old 06-20-2012, 07:05 PM   #12
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Default Re: Use of avgas?

It was easy to see who used avgas in their cars,in our squadron,at Barbers Point,Oahu Hawaii,back in the early sixties.Their tailpipes had a light yellow color inside,from the lead deposits.
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Old 06-21-2012, 04:48 AM   #13
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Default Re: Use of avgas?

I used to run it in my old Ford tractor. The unusual odor was interesting and the tractor seemed to like it. However, the plugs needed cleaning sometimes. People used to pull up to the airport avgas pump and fill muscle cars and race cars on Friday night.

Ironically, my airplane had a certificate to run auto gas in it.
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Old 06-21-2012, 08:50 AM   #14
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Default Re: Use of avgas?

One of the helicopters I specialize on has a higher than normal performance engine that was specifically designed for that application. It has 10:1 compression and was certified for 100/130 grade fuel but has to use 100LL now due to availability. I've found that aircraft that fly more at lower power settings can have problems with lead fouling even with the 100LL fuel. Automobiles would likely have the same problem only worse since they seldom run all out unless it's for racing. The EPA allows for fuel usage of leaded fuels for off road purposes like racing, aviation, and marine applications otherwise it's not worth the extra expense. There is a fine of up to $10,000 in the USA for use of leaded fuels for "on road" applications but I've never seen the gas police catch anyone that I know about.
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Old 06-21-2012, 09:13 AM   #15
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Default Re: Use of avgas?

100LL has 4 times the lead as the former leaded gasoline. We had an STC to use 87 no lead auto fuel in our Cessna, but was not required to add any lead. We also ran regular gas in our stockcar back in the 60's when others were running Snoco 260.
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Old 06-21-2012, 09:38 AM   #16
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Default Re: Use of avgas?

This pdf shows 0.55 gm lead/liter for 100LL. http://www-static.shell.com/static/a..._100ll_pds.pdf The old pre 70s leaded gasoline had a maximum of 3.18 gms/gallon which is 50% or so higher than today's 100LL
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Old 06-21-2012, 10:41 AM   #17
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Default Re: Use of avgas?

I remeber reading somewhere that the reason avgas had the broad ratings back in the day like 100/130 and 115/145 was to have an indicator of lead content versus mixture ratio. In some cases they were dealing with mixtures as lean as they could get on say a big 4360 or 3350 radial and the 115 would be the highest content for full best lean at high altitude and then 145 at full rich for take off. Most fuels that used lead were rated with a max content but they also had a minimum content so it could have a lot of TEL in there or a minimum quantity per gallon. I always figured the refiners used the minimum they could get away with for Ethyl Mogas since it wasn't making them any more money using the max. The only thing you ever see from the gas police is checking meters for accuracy. They do take samples now and then to test but you know how the government is.

I have an EPA document that mentioned the average TEL content in auto fuel was 2.4 grams per gallon prior to 1973 when they started the no lead process. I think this also includes premium fuels that were available at that time. 100LL by the ASTM has from 1.2 to 2 grams per gallon so they aren't that much different in TEL content from car gas circa 1972. I always wondered how well the stuff stays in supension though. If it sets in a tank a long time it might change the concentrations in the batch.

Last edited by rotorwrench; 06-21-2012 at 01:00 PM. Reason: additional info
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