Tetra-ethyl lead

Dan Thomas said:
Oil refining isn't as simple as it used to be. It's not just distillation anymore. Various catalyzing and other processes such as unification and alkylation are employed to obtain the desired fuel properties. In essence, the molecules of the distillates are taken apart and reassembled into something not achievable by simple cracking.

See http://science.howstuffworks.com/oil-refining5.htm

Dan
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Very true - just trying to keep it "simplified"

Gary
 
Missa said:
Not a Chem E so... When you put something in storage that you will not use all winter (boat, lawn mower, motorcycle) you can add a fuel stabilizer to it, or when you bring it out of storage it will tend to back fire, cough and not make full power(at least my jetski did on old fuel). Avgas is formulated so that you can fill you tanks and let it sit for 3-4 months and it still have relatively the same fuel.



It's a matter of QC but saying mogas and avgas are the same is like comparing the Geek in his parents basement playing D&D with greasey hair and pmiples who last showered sometime last month to the sucessful trim athletic well groomed Doctor and saying "well they are all human so they are the same." Uhm, no. They are very very diffrent.
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Meh...whatever...I disagree with you... and explained why.
 
Cap'n Jack said:
Meh...whatever...I disagree with you... and explained why.
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You can disagree with me all you want... people disagree with accepted science every day.

Science fact doesn't care. Act on your belief at your own risk.
 
dmccormack said:
Actually, every advance in science arose from contradiction of the "accepted science."
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You shut your mouth. The earth is flat, the center of the universe, and flies just appear out of nowhere!
 
EdFred said:
You shut your mouth. The earth is flat, the center of the universe, and flies just appear out of nowhere!
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...people get sick and die from "bad air", disease is the result of imbalance of vital humors, ground pumice is a great dentifrice, smoking helps clear the lungs, the planet will run out of oil by 1980,1983,1986,1990,1997,2000,2010, there will be an new ice age caused by pollution, there will be a new heat wave caused by pollution,

ad naseum
 
dmccormack said:
Actually, every advance in science arose from contradiction of the "accepted science."
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True but if you choose to not beleive observational fact that fuel degrades over time... He can live with the consiquences if he decides to fly on old mogas. Of course then he'll just blame someone else like the engine manufacturer for not making power on fuel that can't provide enough potential power. And then we all loose.
 
Missa said:
True but if you choose to not beleive observational fact that fuel degrades over time...
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It matters not if it is mogas or avgas. In a non-sealed system, both will deteriorate via oxidation and other mechanisms.

He can live with the consiquences if he decides to fly on old mogas. Of course then he'll just blame someone else like the engine manufacturer for not making power on fuel that can't provide enough potential power. And then we all loose.
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Nice application of the slippery slope logical fallacy...
 
Missa said:
True but if you choose to not beleive observational fact that fuel degrades over time... He can live with the consiquences if he decides to fly on old mogas. Of course then he'll just blame someone else like the engine manufacturer for not making power on fuel that can't provide enough potential power. And then we all loose.
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There are many thousands of airplanes running on mogas (with -- and in some cases without -- an STC).

Many older engines were certified for "73 octane aviation fuel."

(Where can I find some of that?)

I'll admit to leaving gas in my motorcycle's tank over the winter, and on the first warm day in spring, start it right up with no ill effects. So I don't think it's unstable -- perhaps not as stable as avgas over the long run.

:dunno:
 
dmccormack said:
I'll admit to leaving gas in my motorcycle's tank over the winter, and on the first warm day in spring, start it right up with no ill effects. So I don't think it's unstable -- perhaps not as stable as avgas over the long run.

:dunno:
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No where did I say mogas was unstable. It is less stable then avgas which you have agreed to so :dunno:

Fly at your own risk but when you go down try not to take the rest of GA with you.
 
dmccormack said:
There are many thousands of airplanes running on mogas (with -- and in some cases without -- an STC).
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Yep. And without mass carnage, even.

I'll admit to leaving gas in my motorcycle's tank over the winter, and on the first warm day in spring, start it right up with no ill effects. So I don't think it's unstable -- perhaps not as stable as avgas over the long run.

:dunno:
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You didn't use Stabil? :D I find it ironic that Stabil has a shelf life of 2 years...
 
Trapper John said:
Yep. And without mass carnage, even.
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That's the problem with over-safety -- after a while, folks become complacent about REAL hazards. Mogas isn't the hazard -- not enough gas is more likely.


Trapper John said:
You didn't use Stabil? :D I find it ironic that Stabil has a shelf life of 2 years...
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No -- I was lazy -- by January I was thinking, "Oh well -- we'll see if it starts..."

First warm day in March -- vroooomm...

:D
 
I've never used Stabil in my lawn mower/motorcycle/anything, and they always start and run fine after the winter. When I bought my first Jag, it had been sitting for about 3-4 years with the same fuel in the tank. Started right up and ran fine (although it did ping a bit before I filled it with fresh gas). Maybe I'm just lucky.

One thing to remember which I think has been missed - the planes out there that are running on MoGas were certified for lower anti knock ratings in the first place. There is a big difference between taking an engine that was certified for 80 (or 73) and running it on 87-93 (assuming same scale) than taking an engine certified for 100LL and running it on 93-94. In the first case, you still have a fuel that's enough resistant to knock that some deterioration still leaves you well above acceptable limits. In the second case, you are reducing the anti-knock properties of the fuel. This ignores anything regarding vapor pressure, longevity, etc. Understanding that not all engines are the same (a TIO-540-J2BD is not an O-360-A1A), you may have certain cases where engines could theoretically perform just fine with a particular fuel. However unless there is some testing to back up that theory, it would be ill-advised to just dump the fuel in and go.
 
Ted DuPuis said:
One thing to remember which I think has been missed - the planes out there that are running on MoGas were certified for lower anti knock ratings in the first place. There is a big difference between taking an engine that was certified for 80 (or 73) and running it on 87-93 (assuming same scale) than taking an engine certified for 100LL and running it on 93-94. In the first case, you still have a fuel that's enough resistant to knock that some deterioration still leaves you well above acceptable limits. In the second case, you are reducing the anti-knock properties of the fuel. This ignores anything regarding vapor pressure, longevity, etc. Understanding that not all engines are the same (a TIO-540-J2BD is not an O-360-A1A), you may have certain cases where engines could theoretically perform just fine with a particular fuel. However unless there is some testing to back up that theory, it would be ill-advised to just dump the fuel in and go.
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I think you addressed this earlier, and I don't think anyone is disagreeing with the fuel requirement differences.

I just wish we could pull up to a self-serve pump just like we do for cars -- 83, 87, 91, and 93 octane all lined up and ready to go.
 
I use Mogas in my plane exclusively, and have been for the past 2 yrs with no ill effects. I never have plug fowling either. As for fuel stability, My father and I used to crush cars for re-cycling. We would take our crusher into a salvage yard and crush cars with a crusher powered by a 8-cylinder gas-burning engine. We never bought fuel for the crusher because we would use the fuel out of the cars that we crushed. Most of the fuel that we used was derived from cars that had sat in a scrapyard for 5+ yrs. We never had problems with fuel contamination. Just sayin'
 
dmccormack said:
I think you addressed this earlier, and I don't think anyone is disagreeing with the fuel requirement differences.

I just wish we could pull up to a self-serve pump just like we do for cars -- 83, 87, 91, and 93 octane all lined up and ready to go.
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If there were 100,000,000 airplanes in the country like there were cars, we could. Guaranteed.
 
dmccormack said:
I just wish we could pull up to a self-serve pump just like we do for cars -- 83, 87, 91, and 93 octane all lined up and ready to go.
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I agree. However, that will not happen until there is enough demand for those different kinds of fuel to justify it. The gas companies don't want to produce different fuels and the FBOs don't want to have multiple tanks/trucks. It just doesn't make economic sense.
 
Ted DuPuis said:
I agree. However, that will not happen until there is enough demand for those different kinds of fuel to justify it. The gas companies don't want to produce different fuels and the FBOs don't want to have multiple tanks/trucks. It just doesn't make economic sense.
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Does it require different trucks? I thought the octane boosting was done by mix variations at the point of sale?

:dunno:
 
dmccormack said:
Does it require different trucks? I thought the octane boosting was done by mix variations at the point of sale?

:dunno:
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Often it does. The addition of additives is sometimes done at the refinery, sometimes at a major terminal. Unfortuately I don't have good information on which are which. It is true that if TEL is the additive, the delivery truck is dedicated to leaded fuel. Decontamination of the truck is difficult and expensive.

I know of no additives that are done at point-of-sale (the actual gas pump).

Gary
 
dmccormack said:
Does it require different trucks? I thought the octane boosting was done by mix variations at the point of sale?

:dunno:
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Separate tank for each fuel.

I'm not sure what kind of margin an FBO can get on mogas, but the cost to put in an above ground tank and dispensing would not be cheap. Regular above ground fueling stations for ground vehicles run $20-25k and I'm sure FAA-approved stuff costs more than that. So it's probably not a good financial proposition for the FBO in a lot of cases, unless there's a big volume of mogas to be sold.
 
Trapper John said:
Separate tank for each fuel.

I'm not sure what kind of margin an FBO can get on mogas, but the cost to put in an above ground tank and dispensing would not be cheap. Regular above ground fueling stations for ground vehicles run $20-25k and I'm sure FAA-approved stuff costs more than that. So it's probably not a good financial proposition for the FBO in a lot of cases, unless there's a big volume of mogas to be sold.
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If that's the case -- separate tank for each grade of fuel (87,89,91,93) -- then the costs would definitely be prohibitive.
 
dmccormack said:
If that's the case -- separate tank for each grade of fuel (87,89,91,93) -- then the costs would definitely be prohibitive.
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It is the case.
 
Dale Young said:
I use Mogas in my plane exclusively, and have been for the past 2 yrs with no ill effects. I never have plug fowling either. As for fuel stability, My father and I used to crush cars for re-cycling. We would take our crusher into a salvage yard and crush cars with a crusher powered by a 8-cylinder gas-burning engine. We never bought fuel for the crusher because we would use the fuel out of the cars that we crushed. Most of the fuel that we used was derived from cars that had sat in a scrapyard for 5+ yrs. We never had problems with fuel contamination. Just sayin'
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And what would result if your crusher got bad gas??? Would anyone die or would you just fail to crush a car?

Engine problems in a plane on take-off =/ engine probems in a car crusher.
 
Ted DuPuis said:
I've never used Stabil in my lawn mower/motorcycle/anything, and they always start and run fine after the winter. When I bought my first Jag, it had been sitting for about 3-4 years with the same fuel in the tank. Started right up and ran fine (although it did ping a bit before I filled it with fresh gas). Maybe I'm just lucky.
Did gthey make full power on the 4 yr old gas???

Risk of a car/mower/motorcycle/jetski not making power: goes a little slower

Risk of an airplane not making power on old gas: hit the 50 ft tree on takeoff at the end of the runway.
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Gary said:
Or, compartmented tanks. These are fairly common.

Gary
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So the tanker truck that pulls up fills only one section? Or are the tanker trucks also compartmented?

IIRC on Car Talk they said the fuel octane you get at first is always whatever the last person pumped -- whatever was held in the line by the check valve.
 
dmccormack said:
So the tanker truck that pulls up fills only one section? Or are the tanker trucks also compartmented?

IIRC on Car Talk they said the fuel octane you get at first is always whatever the last person pumped -- whatever was held in the line by the check valve.
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To the best of my knowledge, what's in the fuel line from the pump does get mixed up with whatever was pumped last.

Yes there are compartmented tanker trucks.

Gary
 
dmccormack said:
I never got the tour of the tanks -- may be worth a look see at my local Sunoco.:yesnod:

(IIRC, they sell 87, 89, 91, and 93!)
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Back in the leaded gas days they had two fuels and blended them at the pump to get all the middle grades. I assume, but don't know, that they still do the same. It's been a long time since I hung out at gas stations...
 
Capt. Geoffrey Thorpe said:
Back in the leaded gas days they had two fuels and blended them at the pump to get all the middle grades. I assume, but don't know, that they still do the same. It's been a long time since I hung out at gas stations...
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I seem to remember Gulf stations in the early '70s having the blender pumps that made 4 grades out of regular leaded and premium leaded.

Around here, it's all separate tanks. But we have 87 octane without ethanol, 89 octane that has 10% ethanol and 91 octane without ethanol. Plus E-85 and diesel at some stations...
 
Missa said:
You can disagree with me all you want... people disagree with accepted science every day.

Science fact doesn't care. Act on your belief at your own risk.
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Missa, as a practicing chemist with advanced degrees, I do find your comment insulting. You didn't know my background...but please don't tell me how science is supposed to work, ok?
 
dmccormack said:
So the tanker truck that pulls up fills only one section? Or are the tanker trucks also compartmented?

IIRC on Car Talk they said the fuel octane you get at first is always whatever the last person pumped -- whatever was held in the line by the check valve.
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Which is why if you are buying the higher octan stuff, look for the pumps with seprate hoses.
 
Cap'n Jack said:
Missa, as a practicing chemist with advanced degrees, I do find your comment insulting. You didn't know my background...but please don't tell me how science is supposed to work, ok?
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If you have a advanced sicence degree please tell eveyone here who says that gas breaks down, why they are wrong.
 
dmccormack said:
I never got the tour of the tanks -- may be worth a look see at my local Sunoco.:yesnod:

(IIRC, they sell 87, 89, 91, and 93!)
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The car gas stations may have it differently, but I'm pretty sure that the standard for them is one tank for each. The tanker trucks I thought had different compartments in them as well, but I don't work for a gas company.

Sunoco car gas does have more grades available at the pump (although they stopped selling 94), but most car gas stations have three - typically 87, 89, and 91/2/3. Sam's Club has two - 87 and 93. All have an additional one for diesel, if they have diesel.

I'll bet that my local Sam's Club sells more 93 in a day than my airport sells 100LL.
 
*checking the calendar*

Yep, looks about right.
 
Missa said:
You can disagree with me all you want... people disagree with accepted science every day.

Science fact doesn't care. Act on your belief at your own risk.
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When it comes to Chemistry - there isn't much Jack could say that I wouldn't blindly agree with. I don't think you're really understanding what he was saying.

There is a nice way to disagree with someone and there is a rude way. Unfortunately it seems you've taken the rude route. If I were Jack, after your comment, I'd have no desire to educate you any further.
 
jesse said:
When it comes to Chemistry - there isn't much Jack could say that I wouldn't blindly agree with. I don't think you're really understanding what he was saying.

There is a nice way to disagree with someone and there is a rude way. Unfortunately it seems you've taken the rude route. If I were Jack, after your comment, I'd have no desire to educate you any further.
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He didn't seem to want to educate to begin with. He said he didn't think it sat around degrading but gave nothing more then his thoughts and then other people gave contridictory explainations and he just said. I disagree, enough said. I have no idea his petigree and he doesn't want to explain why he thinks mogas is infiniatly stable so I can only give him the credit he is showing...
 
Missa said:
He didn't seem to want to educate to begin with. He said he didn't think it sat around degrading but gave nothing more then his thoughts and then other people gave contridictory explainations and he just said. I disagree, enough said. I have no idea his petigree and he doesn't want to explain why he thinks mogas is infiniatly stable so I can only give him the credit he is showing...
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You don't handle someone disagreeing with you well do you? Respecting the thoughts of others is pretty damn important to having a constructive conversation. You were making statements that weren't respectful and he stated he disagreed and left it at that. I'm not sure why you think he is obligated to tell you anything.

No one is obligated to do anything for you. Airplane rides or chemistry explanations. The more you act like they are, the less interested they'll be.
 
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