Mogas

[timwinters]

Consider verifying if the FBO is actually delivering E0.

oh, yes. Especially if you buy 0E at a gas station on the street. I've posted this here before...

This is what I use. A test tube style rain gauge with a cork carved to fit. Fill to 1" with water and then to 4.5" with mogas. Shake, and when the mixture "re-separates" the water level will rise to 1.35" if the gas is 10E (10% of 3.5" = 0.35"). Quite noticeable to say the least. It only takes a few seconds for the water to settle out, works every time.

 

[baboss]

I'm thankful that our local HyVee has Alcohol free mogas. Our O300-D seems to like it just fine. I test it every time I haul the 5 gallon cans to the station w/ the Quick Check solution available here.

Whenever this comes up I reference one of Ed Kollin's (inventor of Camguard) articles on sticking valves which contains this snippet on mogas:
"Unleaded autofuel use is fairly widespread and it would be utilized more because it is cheaper. However, alcohol free autofuel is not widely available at airports. Autofuel does not contain lead, so smaller lower powered engines that use it do not suffer from plug fouling. However, autofuel contains olefins as a cheap way to boost octane. If you remember, olefins are reactive, double bond containing molecules (unsaturated or dehydrogenated) that can readily polymerize, or
oxidize, into varnish films as previously discussed. It is the olefins in autofuel that make it stink, limit shelf life, and cause it to form gum and varnish deposits in fuel systems.
Many people have great success with autofuel. However, many engine shops claim that autofuel causes premature cylinder problems, including valve sticking and piston top and ring land erosion, so they will not warranty engines that use it. If you use autofuel, you should use it exclusively. Equally important, mixing unleaded autogas with avgas provides the engine with the reactants to maximize deposits by providing olefins from the autofuel, and lead particles from the avgas."

If you fly often and change your oil often I'd guess that it's not a huge deal otherwise folks would have seen problems by now...

 

[tawood]

My o-320 (150 hp) likes Mogas just fine...I burn mogas from home (hauled in three 5-gallon cans) and 100LL away from home. I do test EVERY batch of mogas though, and if using mogas, you should too (I have once in two years found my supposed ethanol-free mogas contained ethanol, when I bought from a new source). One thing I've noticed is my sparkplug lead fouling has dropped dramatically since switching to mostly mogas.

 

[midwestpa24]

Remember when using auto fuel, just because it says no ethanol, doesn't mean it is no ethanol. The fuel in the delivery tankers often gets mixed from load to load without cleanout. You will be getting some of whatever was left in the truck from the previous load. That is the advantage to AvGas, they can't use that tanker for anything else without a major cleanout.

The biggest difference between autogas and avgas is not how it runs in the engine, it is the quality control from refinery to user. There are quality checks at every step that auto gas does not get.

 

[Tom-D]

Remember when using auto fuel, just because it says no ethanol, doesn't mean it is no ethanol. The fuel in the delivery tankers often gets mixed from load to load without cleanout. You will be getting some of whatever was left in the truck from the previous load. That is the advantage to AvGas, they can't use that tanker for anything else without a major cleanout.

The biggest difference between autogas and avgas is not how it runs in the engine, it is the quality control from refinery to user. There are quality checks at every step that auto gas does not get.

The biggest difference between the two is the ash, carbon (what ever you want to call it) deposit they leave behind. The deposits with lead in them are softer. They scrape away easier. specially when they are in your valve guides.

 

[aftCG]

I burn mogas because it is nearly half the cost of 100ll. It’s worth it to haul around the 5 gal jugs. I have a high wing so dumping the fuel back into the tank is a pain. I just dump it in one of the 5 gal jugs. Easy peasy.

Wait. Dumping a small sample back in your high wing is difficult but hoisting multiple five gallon jugs up there every time you fly is no problem?

 

[aftCG]

oh, yes. Especially if you buy 0E at a gas station on the street. I've posted this here before...

This is what I use. A test tube style rain gauge with a cork carved to fit. Fill to 1" with water and then to 4.5" with mogas. Shake, and when the mixture "re-separates" the water level will rise to 1.35" if the gas is 10E (10% of 3.5" = 0.35"). Quite noticeable to say the least. It only takes a few seconds for the water to settle out, works every time.

I like that idea, and concur that just because it says E0 doesn't mean much.

One question. What do you do with the water/gas mixture once you know?

 

[timwinters]

If you use autofuel, you should use it exclusively. Equally important, mixing unleaded autogas with avgas provides the engine with the reactants to maximize deposits by providing olefins from the autofuel, and lead particles from the avgas."

I guess I don't understand his point, Brock. Sure you have the deposits from both but both are proportionately reduced. Unless he's stating that the mixture somehow reacts and makes each worse, but I don't take that away from his quote.

I have a lot of respect for Ed but this one sounds more like one of Mike Busch's numerous ill thought out theories than Ed's.

 

[timwinters]

I like that idea, and concur that just because it says E0 doesn't mean much.

One question. What do you do with the water/gas mixture once you know?

I dump it slowly into a small engine (lawnmower, etc) until I get back down to the water and then I toss the rest. Very little fuel remains at that point.

Also, at the gas station, I always pump the first gallon into my vehicle before beginning to fill the 5 gallon cans just to make sure any E10 that remains in the hose doesn't go into the plane.

 

[catmandu]

Yeah, we do have a lakeside marina that carries "real" gasoline, but it is 30+ miles away. My real issue is my higher compression 0-320 and a low-wing airplane. Mogas not recommended as far as I can tell.

Not sure of your piston setup, but from another forum, from a respected source:

7:1 compression ratio, in an O-320, is had by installing 75413 or equivalent pistons and it is generally accepted to burn mogas with 87 octane and above with that compression ratio. Take off Hp is in the range of 150 with those pistons.

8.5:1 is the high compression ratio for the O-320 and it is attained by use of 75089 or equivalent pistons. It is generally accepted to run mogas of 91 octane and above with this compression ratio. Rated power is 160 HP with those pistons

9:1 compression is attained by use of the LW-15357 or equivalent, in the O-320, and it is generally accepted that you should use 100LL above with this engine. You should see around 164 HP at take off, with those pistons.

You're experimental, just go to the dark side! I know that my 9:1 pistons will run 93 octane E10 mogas.

 

[dell30rb]

Your engine oil will thank you.

I’ve been quietly educating fellow pilots about dumping sumped avgas on the ground for a few years now. It’s just a habit that we don’t need to be doing. The ‘educating’ part is tough because the topic doesn’t come up very often outside of the training environment. I try to come up with a humorous, non-confrontational way to mention dumping and fortunately have the folks in Boulder to pick on. That was fine until I had a flight review in Boulder.

Anyway, fuel is to be consumed in an engine. It doesn’t belong on the ground.

I use a GATS jar and generally dump the fuel back in the tanks, however I haven't seen any real solid data showing that the small amounts of 100LL being dumped by pilots as they sump tanks has ever amounted to anything beyond a very local contamination of topsoil around the immediate ramp area.

https://www.sciencedirect.com/science/article/pii/S0045653516313285

This article indicates elevated concentrations around fueling areas (likely caused by spills) however the samples were still below anything that would be considered hazardous.

 

[FormerHangie]

I dump it slowly into a small engine (lawnmower, etc) until I get back down to the water and then I toss the rest. Very little fuel remains at that point.

Also, at the gas station, I always pump the first gallon into my vehicle before beginning to fill the 5 gallon cans just to make sure any E10 that remains in the hose doesn't go into the plane.

The station where I get mine has a separate nozzle for E0 gasoline. Note: I don't have an airplane, but I use it in my car just to provide some demand for E0 fuel.

 

[Stingray Don]

Wait. Dumping a small sample back in your high wing is difficult but hoisting multiple five gallon jugs up there every time you fly is no problem?

No. It is just easier to dump the sample in the gas can than climbing back up to dump it in the tank.

 

[Tom-D]

Just a question, doesn't mo-gas have a different specific gravity than 100LL ?
isn't there a tester for that?

 

[Tom-D]

how long do you wait to sump tanks after filling?

 

[denverpilot]

We’ve run MoGas in our 182 and have the EAA STC. For a very long time we couldn’t find MoGas without ethanol anywhere close enough to the airport to make it worth doing. Now there’s a gas station with the stuff a mile away.

We built a MoGas tanker trailer and stashed it in our hangar. Then we learned the airport bans trailers inside the security fence. LOL. So it’s never been used.

We also learned that to keep MoGas or anything else from competing with them on the field, the airport and FBOs require anyone “handling fuel” to be formally trained at many hundreds of dollars per year. Being a checkbook and watch a safety video online titled, “Don’t be a dumbass.”

We also learned that any “storage of fuel” in hangars is prohibited. No mention of how we’re all supposed to drain our airplanes every time we put them away. They don’t seem to have an answer for that question informally. Nobody’s asked formally.

About the only reason I have left to keep my Dodge Cummins is to buy it a big fuel tank and use it to take MoGas to the hangar and fuel the airplane and flip the whole bureaucratic BS mess the bird until they tell me I have to stop. Then just go do it at night or when they’re busy. LOL.

Wish there was enough demand that one of the competing fuel FBOs would just offer the damn stuff on the field. You’d think at the third busiest GA airport in the country they could bother putting in another tank or buying a truck. They both suck for not doing so.

Samples go in the tug or back in the wing unless they’re contaminated. Never had a contaminated one on our aircraft so they get put somewhere useful.

Predicting where the gascolator pull valve will barf is impossible and I’m not carrying a large bucket around with fuel residue and fumes in the back of the airplane to catch it. I limit the pull on that handle to as short as I can and usually inside our hangar. Tiny pull and go look for water bubbles in the tiny puddle. If it’ll make anyone feel better, I’ll stat lighting it on fire.

No flipping clue how you’d catch it away from home. Not going to reach up in there and put some container soon to be full of fuel inside a hot cowl near a hot engine, because I’m not fond of visits to the burn ward.

We only have three sumps. When sumping a newer lawyer driven Cessna bring a bucket or at least a large GATTS jar. The tube thing won’t hold even small samples from the ten thousand drain points for the first flight of the day. Budget an extra half hour. Freaking Cessna.

 

[Tom-D]

Next question, mo-gas has different chemicals to make up the recipe, don't they all have different boiling points? if they do, why can't they be run thru an evaporator and separated ?

 

[timwinters]

Don't...

Feed...

The...

Troll...

 

[coloradobluesky]

Some of the STC's for mogas for Lycoming engines recommend running one tank of 100LL every 20 tanks. There is no problem mixing mogas and 100LL (if you can run on it without knocking and have the STC etc).

 

[UngaWunga]

Next question, mo-gas has different chemicals to make up the recipe, don't they all have different boiling points? if they do, why can't they be run thru an evaporator and separated ?

Because it's Monday, the moon is full, and I like pie. Duh.

 

[edo2000]

Not sure of your piston setup, but from another forum, from a respected source:

7:1 compression ratio, in an O-320, is had by installing 75413 or equivalent pistons and it is generally accepted to burn mogas with 87 octane and above with that compression ratio. Take off Hp is in the range of 150 with those pistons.

8.5:1 is the high compression ratio for the O-320 and it is attained by use of 75089 or equivalent pistons. It is generally accepted to run mogas of 91 octane and above with this compression ratio. Rated power is 160 HP with those pistons

9:1 compression is attained by use of the LW-15357 or equivalent, in the O-320, and it is generally accepted that you should use 100LL above with this engine. You should see around 164 HP at take off, with those pistons.

You're experimental, just go to the dark side! I know that my 9:1 pistons will run 93 octane E10 mogas.

That IS interesting. Do you run 93/E10 regularly? Do you mix it with 100LL? When researching certified STCs, I had read that the 0-320/150hp was OK with mogas and the 160hp version was not. Also I noted that vapor pressure problems were more likely with low wing airplanes due to lower line pressures upstream of the carb. The combination of that, plus the fact I'm now in an "E10-only / 91 octane max" region, more or less ended my inquiries into using mogas. I know that I can do pretty much what I want, legally, but to be conservative, I was looking for a reasonable track record - e.g., a near identical engine/fuel system configuration with many thousands of hours of cumulative successful use... . My little RV-9A is already very fuel efficient compared to every airplane I owned before, but it would still be great to be able to use mogas. I'm definitely planning to investigate this more. Thanks!

 

[DaleB]

Next question, mo-gas has different chemicals to make up the recipe, don't they all have different boiling points? if they do, why can't they be run thru an evaporator and separated ?

To what end?

 

[Clark1961]

To what end?

Tom must think he is the only person who has heard that the boiling point of mixtures is not the same as the boiling point of pure components. He has prolly forgotten that a fractionating tower does just what he claims boiling can't do.

 

[Tom-D]

To what end?

If you can't get E free, make our own.
I wonder what it would take.

 

[baboss]

I guess I don't understand his point, Brock. Sure you have the deposits from both but both are proportionately reduced. Unless he's stating that the mixture somehow reacts and makes each worse, but I don't take that away from his quote.

I have a lot of respect for Ed but this one sounds more like one of Mike Busch's numerous ill thought out theories than Ed's.

I hear you. Taken in the context of the whole article I think he is talking about the mix reacting, along with all of the other combustion byproducts, and creating some nasty deposits. I could be reading into it though. Of course you can counteract all this by purchasing and using his product

I do the same as Tim and pump 1 or 2 gallons into my truck to “clear out” the gas station lines to get my alcohol free mogas in the 5 gallon cans.

 

[Tom-D]

Tom must think he is the only person who has heard that the boiling point of mixtures is not the same as the boiling point of pure components. He has prolly forgotten that a fractionating tower does just what he claims boiling can't do.

Where did I make any claims?
really wouldn't require fractation, over again. the still principal would work, I wonder if you could control temps that close.
Make a little apparatus to get the Alkie out, sell the machine to those who can't get E free.

 

[Tom-D]

Also I noted that vapor pressure problems were more likely with low wing airplanes due to lower line pressures upstream of the carb.

The aircraft with fuel pumps that have a negative pressures between the tank and the pumps have vapor lock problems. The fuel vaporizes, cavatates the pump and the pump can't prime itself again.

 

[Clark1961]

Where did I make any claims?
really wouldn't require fractation, over again. the still principal would work, I wonder if you could control temps that close.
Make a little apparatus to get the Alkie out, sell the machine to those who can't get E free.

You made claims by inference. Distillation would not work because too many hydrocarbons would also boil. Fractionation would be the only way to "mostly" separate the ethanol because the properties are similar to hydrocarbons in the gasoline mixture. Even with fractionation the end product would not be gasonline components and ethanol, it would be some gasoline components and a hydrocarbon-ethanol mixture.

 

[Tom-D]

You made claims by inference.

No its just the way you read it.

 

[Tom-D]

Distillation would not work because too many hydrocarbons would also boil. Fractionation would be the only way to "mostly" separate the ethanol because the properties are similar to hydrocarbons in the gasoline mixture. Even with fractionation the end product would not be gasonline components and ethanol, it would be some gasoline components and a hydrocarbon-ethanol mixture.

Auto fuel is auto fuel, they add Ethanol or not. get the Ethanol out, we got mo-gas. the only problem I can see is these light hydrocarbons are very close boiling temps, they'd probably all come off at the same time.
The main purpose of the fracking tower is to pull off the heavy tars and coke, and allow the lighter hydros to separate, auto fuel has neither. Alcohol / ethanol would boil off at about 140 degrees, but all the light hydrocarbons would be gone by then, So all that would remain at 130 degrees is the alcohol.

Addition.
the other name for a fracking tower is a catalyst cracking tower. you'd not have to do this again, we already have the light hydrocarbons, we do not need to re-crack them again.

 

[denverpilot]

You made claims by inference. Distillation would not work because too many hydrocarbons would also boil. Fractionation would be the only way to "mostly" separate the ethanol because the properties are similar to hydrocarbons in the gasoline mixture. Even with fractionation the end product would not be gasonline components and ethanol, it would be some gasoline components and a hydrocarbon-ethanol mixture.

How about adding water and letting it attach to the ethanol and then spinning it?

(You are the hydrocarbon expert. I just remember checking for water in crude by spinning it on the gauger’s pickup truck in a little tiny centrifuge.)

 

[Clark1961]

How about adding water and letting it attach to the ethanol and then spinning it?

(You are the hydrocarbon expert. I just remember checking for water in crude by spinning it on the gauger’s pickup truck in a little tiny centrifuge.)

Might work. Certainly the test for ethanol in gasoline indicates most of the ethanol is pulled to the water side of the phase separation. A lot of the ethanol would be removed but dunno how close it would get to total removal. Maybe several 'wash' cycles would get it all. Some hydrocarbon (but not much) would be lost to the water also.

 

[Capt. Geoffrey Thorpe]

If you have an E-AB with the appropriate materials for fuel lines, pump diaphragms, etc. E-10 is not a big deal. I'll take it over 100LL any day.

 

[timwinters]

How about adding water and letting it attach to the ethanol and then spinning it?

(You are the hydrocarbon expert. I just remember checking for water in crude by spinning it on the gauger’s pickup truck in a little tiny centrifuge.)

As an aside, don't forget that removing ethanol from gas reduces the octane rating by about 2 points, if it's a 10% blend.

Casey's stores around here used to sell regular (87) and "premium" (89) (which is actually mid-grade) for the same price. Everybody would put the mid-grade in their car thinking they were getting a deal. Thing is, it was the same gas coming out of the same tank. This was because 87 was still being pumped up the pipes back then. Once the ethanol was added it became 89 so all regular gas around these parts in the early days of E10 was actually be 89 octane instead of 87. The octane rating on the Missouri pumps doesn't say it IS 87, it says that's the minimum it is.

Now they pump "subgrade" gas (85) up the pipes, add the ethanol, and it becomes 87 and Casey's labels all their pumps accordingly...it's all truly regular now @ 87.

 

[Capt. Geoffrey Thorpe]

As an aside, don't forget that removing ethanol from gas reduces the octane rating by about 2 points, if it's a 10% blend.

Wouldn't surprise me if you also removed other additives (such as detergents) that one wouldn't want removed. And, you are left with hazardous waste with things like Toluene, Ethylbenzene, Acetone, Formaldehyde, Acetaldehyde, and other fun stuff in addition to the ethanol to get rid of.

But other than that, it's a great idea.

 

[Cap'n Jack]

Auto fuel is auto fuel, they add Ethanol or not. get the Ethanol out, we got mo-gas. the only problem I can see is these light hydrocarbons are very close boiling temps, they'd probably all come off at the same time.
The main purpose of the fracking tower is to pull off the heavy tars and coke, and allow the lighter hydros to separate, auto fuel has neither. Alcohol / ethanol would boil off at about 140 degrees, but all the light hydrocarbons would be gone by then, So all that would remain at 130 degrees is the alcohol.

Addition.
the other name for a fracking tower is a catalyst cracking tower. you'd not have to do this again, we already have the light hydrocarbons, we do not need to re-crack them again.

Fracking = hydraulic fracturing, part of the process for extracting crude oil or natural gas from the ground.
"Cracking" = breaking a long chain hydrocarbon to smaller, shorter chain, hydrocarbons. This is NOT distillation. It is NOT fracking either.
You are trying to describe fractional distillation (which isn't fracking) which allows us to get both lighter and heavier hydrocarbons separated from one another and. Gasoline would be included in this, being heptanes, hexanes, pentanes, and octanes (isomers of each) and also alkenes in the same boiling-point range. These are actually considered "lighter" hydrocarbons. They add anti-knock compounds such as xylenes, toluene, and ethanol. Kerosene and Jet A are in a higher-boiling fraction than than gasoline. The stuff left over at the bottom of the fractional distillation column is bitumen, used for roads. Coke is made from coal; petcoke is made in a coker unit which isn't distillation.

 

[Cap'n Jack]

Wouldn't surprise me if you also removed other additives (such as detergents) that one wouldn't want removed. And, you are left with hazardous waste with things like Toluene, Ethylbenzene, Acetone, Formaldehyde, Acetaldehyde, and other fun stuff in addition to the ethanol to get rid of.

But other than that, it's a great idea.

Yeah, you'll get other stuff out too. Toluene is somewhat soluble in water (about 0.5 g/L). Some of the other additives would get into the water too, just as you describe.

 

[Clark1961]

Auto fuel is auto fuel, they add Ethanol or not. get the Ethanol out, we got mo-gas. the only problem I can see is these light hydrocarbons are very close boiling temps, they'd probably all come off at the same time.
The main purpose of the fracking tower is to pull off the heavy tars and coke, and allow the lighter hydros to separate, auto fuel has neither. Alcohol / ethanol would boil off at about 140 degrees, but all the light hydrocarbons would be gone by then, So all that would remain at 130 degrees is the alcohol.

Addition.
the other name for a fracking tower is a catalyst cracking tower. you'd not have to do this again, we already have the light hydrocarbons, we do not need to re-crack them again.

Wrong on soooo many levels...

 

[Clark1961]

No its just the way you read it.

No, it’s the way you wrote it.

 

[timwinters]

Wrong on soooo many levels...

Has anyone ever seen Henning and TomD in the same room?