How Does MoGas work?

SixPapaCharlie

SixPapaCharlie

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I was doing my daily daydreaming on trade a plane and I came across a few planes that take mogas.

Is that just regular unleaded car fuel?
I don't see any airports near me that carry it and the 2 I do see, it is only about 10 cents per gallon cheaper than 100LL

How does it work?
 
Also are mogas and avgas mutually exclusive or do these engines run on both?
 
SixPapaCharlie said:
I was doing my daily daydreaming on trade a plane and I came across a few planes that take mogas.

Is that just regular unleaded car fuel?
I don't see any airports near me that carry it and the 2 I do see, it is only about 10 cents per gallon cheaper than 100LL

How does it work?
Click to expand...

To my knowledge, all planes that are allowed to use Mogas are authorized by STC only (i.e. no legacy aircraft allows mogas in the TCDS). There are two major STC providers, one is EAA, the other Peterson. The STC providers tested many different airframes. Those that passed generally got an STC available for that engine/airframe combination. Many engines failed testing for a variety of reasons and many airframe types were never tested; neither group has an STC available. Assuming that the engine/airframe combo is eligible for the STC, you have to purchase the STC for that specific airplane (it seems that most eligible planes had STCs purchased for them years ago).

There is no STC that allows for the use of ethanol-containing mogas, thus you are stuck not using anything from a local pump and nowadays the ability to use mogas doesn't really mean anything for most pilots. There is a movement in congress to repeal the ethanol mandate. Until then, it is very hard to find ethanol free mogas. You can use google to find websites that list places to purchase ethanol free gas.

Even if you have a local source (neighborhood gas station with ethanol-free gas), getting it on the airport and refueling yourself can get in trouble (i.e. is prohibited) on some airports. There is the whole transportation of 20-60 gallons of gas thing too, storage.

Long story short, not very helpful unless you got a friend in the business or are stopping at an airfield where mogas is available and you have an STC.
 
SixPapaCharlie said:
Also are mogas and avgas mutually exclusive or do these engines run on both?
Click to expand...

Eligible engines/airframes can run on both. You can mix the two gases together. Note that mogas has a significantly shorter shelf life than mogas (or so the conventional wisdom goes).

Many engines and pilots prefer no lead if/when available.

If it helps, I have a little runabout 150. It had a STC for mogas when I bought the plane. As cheap as I am, I've never had an opportunity to exercise the mogas option. For most of us, because of the ethanol mandate, the mogas STC is essentially worthless (only cost $100 for the 150 anyway).
 
My 1948 bonanza has an engine that was certified to run 88 octane or higher. An stc was still required to make that 88UL. There are early bonanza gurus that say they have had much better success with mogas than 100ll due to the lead residue. Their recommendation after multiple engine overhauls: get the led out...

I've just been experimenting so far as I don't have a large tank to move 88UL (no ethanol allowed). Regardless, I have no worries with what the EPA and the FAA are up to... At least on the topic of 100LL.

(Yes, it was a selling point for me..)
 
I can buy ethanol free Mogas for $3.60/gallon. Cheapest Avgas nearby is $5-6/gallon.
 
It rapidly oxidizes while under compression with the proper level of oxygen when ignited by a spark. :D
 
SixPapaCharlie said:
Also are mogas and avgas mutually exclusive or do these engines run on both?
Click to expand...

They'll run on both. Most of the time the difference is a piece of paper. To get the STC you have to climb the plane to IIRC 10,000' starting with the fuel at a specific temp, and do it twice with no problems, and the STC is yours. The trick is if it doesn't pass, the remedies may be more expensive than the savings depending on what it takes to prevent the problem, (usually vapor lock). Petersen offered I could use his heater rig if I wanted to give it a go with the 310.
 
brian];1523293 said:
My 1948 bonanza has an engine that was certified to run 88 octane or higher. An stc was still required to make that 88UL. There are early bonanza gurus that say they have had much better success with mogas than 100ll due to the lead residue. Their recommendation after multiple engine overhauls: get the led out...

I've just been experimenting so far as I don't have a large tank to move 88UL (no ethanol allowed). Regardless, I have no worries with what the EPA and the FAA are up to... At least on the topic of 100LL.

(Yes, it was a selling point for me..)
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You Bet! Get the lead out, there is nothing there that's good.

BTW, you can remove ethanol from gas by washing the gas with water and then running it through a water separating filter like a Racor and draining the water and alcohol off. The alcohol will abandon the gas and fuse to the water and then it's easy to remove. Cost a couple hundred to setup a nice rig that you can also use to pump the fuel up into the plane. You can build it all as well as your transport tank on a little flatbed trailer. Figure $2500 to build a decent rig that will assure you alcohol free MoGas and allow you to buy at bulk price from distributors before the gas station, store and pump it into the plane. You also get to pump it into your cars, so you actually have your own little gas station with rack price fuel.
 
I have the auto gas STC on our 0-470-R Continental but we have rarely used it.

The availability is spotty to say the least.

It doesn't make sense to fly too far to get it.
 
Henning said:
You Bet! Get the lead out, there is nothing there that's good.

BTW, you can remove ethanol from gas by washing the gas with water and then running it through a water separating filter like a Racor and draining the water and alcohol off. The alcohol will abandon the gas and fuse to the water and then it's easy to remove. Cost a couple hundred to setup a nice rig that you can also use to pump the fuel up into the plane. You can build it all as well as your transport tank on a little flatbed trailer. Figure $2500 to build a decent rig that will assure you alcohol free MoGas and allow you to buy at bulk price from distributors before the gas station, store and pump it into the plane. You also get to pump it into your cars, so you actually have your own little gas station with rack price fuel.
Click to expand...

And what would the octane rating end up being after washing the ethanol out of unleaded? Is anyone really removing ethanol from autogas as you suggest? Theory is one thing, practicality another.
 
I have the STC on my Grumman and use it very often. There is a gas station near me that sells ethanol free gas for about $4.00/gal compared to $5.75 for 100LL. I generally fly for 1.5 hours at a time on average so I take two 5 gallon cans with me to the airport to top off with. The only down side is mogas is nasty and stinks but is better for the engine. You can't use it on fuel injected engines due to the increased risk of vapor lock.
 
Witmo said:
And what would the octane rating end up being after washing the ethanol out of unleaded? Is anyone really removing ethanol from autogas as you suggest? Theory is one thing, practicality another.
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It's an interesting question, how is it regulated at the pump? The alcohol is added at the rack, not the refinery. I've never worked the rack so I don't know if they have a knock engine back there to test the fuel with, but having worked other jobs on tankers and such, if they have it, I give it 30% that it works.
 
Many of us Rotax guys use nothing but Mogas.

My CT has long legs and can do most trips without getting fuel on the road. I keep fuel in the hangar.

post-6-0-95618300-1376752006.jpg
 
Witmo said:
And what would the octane rating end up being after washing the ethanol out of unleaded? Is anyone really removing ethanol from autogas as you suggest? Theory is one thing, practicality another.
Click to expand...

And what do you do with all the toxic water?
 
MAKG1 said:
And what do you do with all the toxic water?
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You distill the alcohol off in a solar still and use it as fuel and pour the water on the garden. :D In fact, how toxic would m/ethanol laced water be to the garden?:dunno:
 
I'm still confused. At the automobile pumps in my area you can buy gas that has 10% ethanol and gas that has no ethanol. So is the non ethanol fuel mogas???
 
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Henning said:
You distill the alcohol off in a solar still and use it as fuel and pour the water on the garden. :D In fact, how toxic would m/ethanol laced water be to the garden?:dunno:
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If it were only ethanol, perhaps. What else is in there? Benzene is a carcinogen and readily dissolves in both water and ethanol.
 
CharlieTango said:
Many of us Rotax guys use nothing but Mogas.

My CT has long legs and can do most trips without getting fuel on the road. I keep fuel in the hangar.

post-6-0-95618300-1376752006.jpg
Click to expand...

Are you removing the ethanol or buying ethanol free from a gas station?
 
MAKG1 said:
If it were only ethanol, perhaps. What else is in there? Benzene is a carcinogen and readily dissolves in both water and ethanol.
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Yeah, nasty, What is solar still for $10 Alex? It's a ridiculous practice anyway. Look at the expense and waste we go through, raising food prices as well, just to prop up the continued use of antiquated infrastructure. Enough is enough already, it's time to move on.
 
Henning said:
Yeah, nasty, What is solar still for $10 Alex? It's a ridiculous practice anyway. Look at the expense and waste we go through, raising food prices as well, just to prop up the continued use of antiquated infrastructure. Enough is enough already, it's time to move on.
Click to expand...

You aren't thinking distilling the water is going to remove contaminants with lower boiling points, are you?

You'll need a distillation stack for that, and enough chemical engineering knowlege to tune it without making a Superfund site. Ethanol and benzene have similar boiling points, and it will take a precise still to separate them.

And removing benzene from gasoline is likely to lower it's octane.
 
Grum.Man said:
You can't use it on fuel injected engines due to the increased risk of vapor lock.
Click to expand...

The IO-470-J and K in some Debonairs and Bonanzas are eligible for the MoGas STC.
 
MAKG1 said:
You aren't thinking distilling the water is going to remove contaminants with lower boiling points, are you?

You'll need a distillation stack for that, and enough chemical engineering knowlege to tune it without making a Superfund site. Ethanol and benzene have similar boiling points, and it will take a precise still to separate them.

And removing benzene from gasoline is likely to lower it's octane.
Click to expand...

No, I am thinking dis tilling the contaminants with the lower boiling points out and leaving the water.:D

As I said, we shouldn't put it in in the first place, much simpler solution. In order to avoid the problems of gasoline that we add the alcohol to it to begin with, we should just go Electric to Hydrogen and run most everything on electricity/hydrogen generated by whatever can generate electricity. This leaves a low load on petroleum requirements mostly just for aviation (sea borne shipping is swapping to NG at this time and all the current power plants are simple conversions.) and the fossil supplies can be replaced with modern hydrocarbon stock gained from Algae and other modern era source.

We have the technologies, we are just not implementing them to allow them to advance and grow. All because good business ethic goes for sure profits.
 
I have an HKS-700E engine, so I fly on ethanol-free gasoline unless I am on a very long cross-country (unfortunately anything more than 150 nm for me is a very long cross-country). I get it from a local pure-gas station. Due to the distance to the pump and required fuel burn to transport the gas, there aren't any savings, but at least I reduce or eliminate lead.

The station is right next to a bigger airport and I hear that half the field fuels there (I suspect some do not bother with STC even). Their unleaded pure gas is rated (R+M)/2 91, so it goes into Rotaxes easily. I see a number of pilots driving pickup trucks with bed-mounted tanks and pumps.

Now it all is easy if you fly a CTLS that burns 4 gph at 5000 rpm cruise. Even easier for me: my cruise burn is 3.2-3.4 gph. There are limits to how much gasoline you can store and transport. You probably don't want to rely on a 5gal can if you have a twin.
 
Luckily I burn around 6gal/hr so it works for me even though it's a hassle. I save about 15.00 for every 1.5 hours I fly. Nothing earth shattering but when I am just building time the money saved on gas will pay for my annual or hanger rent.
 
TomCC said:
Even if you have a local source (neighborhood gas station with ethanol-free gas), getting it on the airport and refueling yourself can get in trouble (i.e. is prohibited) on some airports. There is the whole transportation of 20-60 gallons of gas thing too, storage.

Long story short, not very helpful unless you got a friend in the business or are stopping at an airfield where mogas is available and you have an STC.
Click to expand...

Utter nonsense, at least in the midwest. There are no airports that prohibit refueling yourself that I'm aware of. Some prohibit refueling inside a hangar, sure, but one could easily argue that even that is perfectly safe if the door is wide open since gas fumes are heavier than air. IIRC it's not legal for an airport to prohibit self-refueling outside if the proper precautions are adhered to but I may be misremembering.

And a MoGas STC is very helpful even if it's not available on your field if you can find non-ethanolized fuel on the street locally and conveniently. My field has MoGas but I rarely buy it there. 93 octane no-ethanol is currently $3.59 on the street here (I just bought 100 gallons Friday), at my field it's $4.45 and 100LL is $5.25. I rarely buy MoGas at my field but I buy a lot of 100LL there since I blend 75/25 MoGas to 100LL.

Witmo said:
And what would the octane rating end up being after washing the ethanol out of unleaded? Is anyone really removing ethanol from autogas as you suggest? Theory is one thing, practicality another.
Click to expand...

Not that I would ever try to remove ethanol from MoGas but ethanol adds 2 octane points to gas and Henning is right, it's added at the terminal after it comes out of the pipeline. This because the ethanol would separate from the gas while being pumped down the pipe. So, if you know someone that works at the terminal that can get you some gas before the poison is added....
 
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SixPapaCharlie said:
I was doing my daily daydreaming on trade a plane and I came across a few planes that take mogas.

Is that just regular unleaded car fuel?
I don't see any airports near me that carry it and the 2 I do see, it is only about 10 cents per gallon cheaper than 100LL

How does it work?
Click to expand...

Its 91 E10 premium auto gas you can get at any gas stations. The Rotax 912 can use it, but the aircraft has to be built to take it because the Ethanol is corrosive and will eat the calk in a fuel tank if not constructed correctly.

I built a small aluminum trailer and DOT approved transfer tank setup that I can pull behind my Lexus. I get 60 gallons at a time and store it in the hangar until needed. My Flight Design CTLSi burns 3.5 gph. So we don't need to put gas in that often.
 
timwinters said:
Utter nonsense, at least in the midwest. There are no airports that prohibit refueling yourself that I'm aware of. Some prohibit refueling inside a hangar, sure, but one could easily argue that even that is perfectly safe if the door is wide open since gas fumes are heavier than air. IIRC it's not legal for an airport to prohibit self-refueling outside if the proper precautions are adhered to but I may be misremembering.
Click to expand...

Actually they can. A local airport here does not permit filling an airplane from gas cans on the airport. The catch is the FAA allows the airport authority to set rules for the "safety" of the airport. Thus this airport deemed filling an airplane from 5 gallon cans unsafe. This is also why it is the only airport around with open hangers and a tarmac full of empty tie downs. On a day with perfect flying weather the only traffic you see are airplanes from ATP or other aircraft from around the area taking advantage of the low congestion. This airport also doesn't not allow owner performed maintenance or repairs in the hangers or on the ramp. You have to rent a spot in the maintenance hanger.
 
You guys are giving me ideas.

I already have a diesel buddy tank in our F-350.

I need to search around for E-free gas and I could probably save quite a bit of moolah if it's nearby. :idea:

 
Henning said:
sea borne shipping is swapping to NG at this time and all the current power plants are simple conversions.
Click to expand...

Funny. My company just had a meeting about the cost savings of converting our vessels to LNG.

I will believe it when I see it but it is certainly the topic dujour in the shipping world. We have a lot of other hurdles before we can even worry about that.
 
I use mogas in my Cardinal 150 hp. I buy it at a couple of stores in the area that sell ethanol free fuels. I buy 87 octane because I have a low compression engine. All gas has the same energy in it per gallon, the octane allows you to run at hgiher compressions without knocking.

I have a 15 qt rubber tub for a fueling kit. Set up goes like this: put the pad on he wing and the empty tub on it. Put the mr filter in the tank, set the 5 gallon can on the tub so its base is higher that the filter and use a siphon with a ballstop to transre the fuel. Most of the fuel will siphon but I end up pouring about a cup when the siphon stops. Pour the trapped fuel out of the filter into the gats jar and then in the tank. Everything fits in the tub and sits behind the pilots seat. It seems difficult but I save 2.50 to thee dollars a gallon or 10 to 15 dollars everytine I lft a five gallon can.
 
SixPapaCharlie said:
Funny. My company just had a meeting about the cost savings of converting our vessels to LNG.

I will believe it when I see it but it is certainly the topic dujour in the shipping world. We have a lot of other hurdles before we can even worry about that.
Click to expand...

I just looked at a project the other day when I was in Genova, they were loading the NG tanks into a Panamax sized container ship. It's happening because the low sulphur Diesel requirements and costs make NG a better deal all around.
 
Grum.Man said:
Actually they can. A local airport here does not permit filling an airplane from gas cans on the airport. The catch is the FAA allows the airport authority to set rules for the "safety" of the airport.
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I guess that's possible but I'd bet they'd be hard pressed to prove fueling out of 5 gallon cans, using the proper precautions, is not safe. I'd also say that's quite rare to have that policy, I've never bumped into it. During the last dozen years or so I've rented a hangar (or tie down) at the following fields, fueled my own aircraft, and never been challenged (of course, I never asked permission either):

Harrison, AR
Springfield, MO
Daniel Field (Augusta, Ga) (the only tie down of the list)
Sandersville, Ga
Albany, Ga
Hazelhurst, Ga
Savannah, Ga
Albertville, AL
Laurel, MS
Monroe, LA
Shade Tree Field (Gulfport, Ms)
Russellville, Ar
Walnut Ridge, AR
Appleton, WI
Watertown, SD
Clintonville, WI
Red Wing, MN (WI)
Cape Girardeau, Mo
Perryville, Mo
Festus, Mo
Lorain, OH
Medina, OH
Mentor, OH (Lost Nation)
Brunswick, GA
Tyler, Tx
Terrell, Tx
Tompkinsville, KY
Marble Hill, MO
Fredericktown, MO

Somewhat in order...and there's likely (quite) a few I'm forgetting,

Never had a problem one.
 
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I never had a problem either until this one airport. I just learned to keep my hangar door closed until done fueling then putting the jugs in my truck since you weren't allowed to store fuel in the hangars either.
 
Grum.Man said:
I never had a problem either until this one airport. I just learned to keep my hangar door closed until done fueling then putting the jugs in my truck since you weren't allowed to store fuel in the hangars either.
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I love that one, go to the next airport board meeting and ***** because people aren't draining their aircraft tanks before putting them away! :goofy:

My Springfield Mo lease said I couldn't store fuel in my hangar. I scratched it out, initialed it and mailed the lease agreement back. Of course I got a phone call questioning my actions. "I'm not draining the fuel out of my plane when I put it away" I said.

Dead silence on the other end. Then "we'll have to review that verbiage". I never heard another word. :wink2:
 
I schlep 5 gallon cans of auto fuel because my Rotax doesn't like the lead. It does, however, tolerate E-10.

The STCs out there for type certificated aircraft only apply to ethanol free gasoline.

Running E-10 in an aircraft without knowing that all of the hoses and components will tolerate it is what you call a real bad idea. You can ask a buddy of mine that lost power on takeoff due to fuel lines swelling shut if you want.

Ethanol is added to blend stock which comes from the refinery with a lower octane rating based on the assumption that the Ethanol will raise it. Plus, gasoline has a lot of additives beyond raw hydrocarbons - some may be more soluble in ethanol than in the gasoline so even if you did separate the ethanol, there is no telling what you would actually be left with in either bucket.
 
*sigh* We ran over 12,000 gallons of sweet unleaded, ethanol free mogas through our Cherokee Pathfinder (235). The savings paid for a LOT of flying, and that big six cylinder engine ran SO much better than it did on 100LL.

Then, we moved to Texas, home of Big Oil, and I couldn't find a source for unpolluted car gas -- so I GAVE my tank/pump away. Argh.

Three months later, I found a station just 20 minutes away with real, no ethanol mogas. :mad2: :mad2: :mad2:

I sure wish I had that rig back!
 
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