Is The Use Of "Pump Gas" or "MoGas" Common In The Mooney World?

[Pinecone]

8 hours ago, PeterRus said:

I think it's not the interval that doubles, it's that unleaded fuel allows for synthetic (aka superior) oil and that doubles the oil change interval. 

And yes, G100UL should change the economics (engine TBO) drastically. 

NO.  Lycoming has a SB out for a couple of years now that approves doubling the oil change interval from 50 hours to 100 hours if you use exclusively unleaded fuels.

In the future, we might get synthetic oils that will allow even longer intervals.

Look at autos.  When conventional oils and leaded fuels, it was 3000 miles between changes.  Now, some of my cars are 15,000 miles intervals.

[Brian2034]

We have a dozen aircraft at our hangar that have been running exclusively mogas for years. With I'm guessing thousands of combined flight hours. Combination of high and low wing.

Luckily we don't have ethanol in our mogas.

BTW our a avgas is $18.00 a gallon or $ 7.00 for mogas (premium unleaded)

[Brian2034]

We have a dozen aircraft at our hangar that have been running exclusively mogas for years. With I'm guessing thousands of combined flight hours. Combination of high and low wing.

Luckily we don't have ethanol in our mogas.

BTW our avgas is $18.00 a gallon or $ 7.00 for mogas (premium unleaded)

We've been sticking to the 50 hr oil changes and the oil comes out virtually like new, very little contamination. Most of the guys also do oil analysis on their used oil and none have found any abnormal issues.

[Fly Boomer]

54 minutes ago, Brian2034 said:

We have a dozen aircraft at our hangar that have been running exclusively mogas for years. With I'm guessing thousands of combined flight hours. Combination of high and low wing.

Luckily we don't have ethanol in our mogas.

BTW our a avgas is $18.00 a gallon or $ 7.00 for mogas (premium unleaded)

Where are you?  $18 sounds like a world record.

[Brian2034]

St.johns Newfoundland Canada

C-YYT

[Igor_U]

4 hours ago, Brian2034 said:

St.johns Newfoundland Canada

C-YYT

Is that CAD or USD?

[Brian2034]

1 hour ago, Igor_U said:

Is that CAD or USD?

CAD

[Igor_U]

13 minutes ago, Brian2034 said:

CAD

I see. And Imperial gal, right? 

IIRC, US gallon was not recognized in Canada...

 

[Brian2034]

2 hours ago, Igor_U said:

I see. And Imperial gal, right? 

IIRC, US gallon was not recognized in Canada...

 

No, US gallon

[A64Pilot]

For whatever it’s worth the University of Tennessee ran a C-310, one engine on “Gasahol” and the other on 100 octane in the early 70’s for testing, they put many hours on it without issues, I don’t know how rich etc they ran it or any particulars, just friends of the Aviation dept head at the time. Gasahol was what they called it in the 70’s during the oil embargo, it wasn’t until much later it got the moniker of E10. I’m certain they took care to keep the cyl head temp down surely, but a good pilot does that anyway.

I know several people that run the Mogas in one wing and 100LL in the other on high compression Lycomings, one of them forgot to switch tanks on landing and after refueling had a hell of a time restarting it. the Mogas had vapor locked much worse than 100 LL. I had a 100 gl tank in the back of my truck for fuel for my boat so for some it’s easy.

The Experimental crowd can burn what the want and there are many that burn Mogas in even 200+ high compression IO-390’s and 360’s.

Basically Mogas is fine at the same power settings that you can’t hurt the engine with mixture, it’s only rarely the extra protection of 100 LL is needed, my bet is below 25” MP and 400F cyl head temps and your fine, but she may vapor lock like you have never seen before if you just shut down for a short time, low wing aircraft are particularly susceptible and harder to certify for Mogas as they have to suck the fuel up.

You can buy test kits to test for Ethanol in fuel but you don’t need one, all you need is a canning jar with graduated marks on it, fill it about 20% with water and the rest with gas, shake it vigorously several times, if the level of water decreases it has alcohol in it as the alcohol mixes with the water and it gets into solution, pure gas won’t absorb water, but E10 will, you know on edit I think it’s the opposite, the level increases as the alcohol is pulled into the water, in fact I’m sure the level increases.

Getting old Sux, you forget things

It would take much different fuel metering but I’d bet Lunch that we could run E85 without issue detonation wise, but surely would require quite a lot of modification.

I just scanned this but at a quick glance it seems E85 made more power than 114 Octane race gas, again just a quick scan, but I had that understanding anyway.

https://www.motortrend.com/how-to/e85-vs-114-octane-race-gas-on-the-dyno-with-a-boosted-small-block/

A major problem with Certifying E85 is first there is no profit because your not supplying it but also it from memory it has no real standard, it can be anywhere from 50% ETH to 85% and be called E85.

In Brazil Embraer has sold the Ipanema that burns pure ethanol in an IO-540 Lycoming, I think almost 20 years? I believe however its burn rate is much higher than if it were burning gasoline. They have pretty much 20 years of data on a decent sized fleet with each aircraft flying on average between 500 and 1,000 hours s year. That’s the kind of test we need I think for whatever fuels get Certified, an honest fleet flying hard for hundreds of hours per year. A ver good argument could be made that Ag planes don’t fly in cold weather nor at high altitude etc and it would be correct.

https://www.cbc.ca/news/world/brazilian-crop-duster-flies-on-ethanol-1.559324

Having said all of that it’s very much an airframe issue and an engine issue, for instance the low compression O-540 in a Maule can be bought factory Certified to burn Mogas, or can be field modified. It adds vents to cool parts of the fuel system and an additional fuel pump, fuel under pressure is much less likely to boil, that’s all vapor lock is really the fuel boils and turns into vapor.

The high compression IO-540 Maules are not Certified to burn Mogas.

I’m not abdicating anyone run Mogas in their mooney, and never believe anything you read on an internet forum  

You cant go wrong or be found at fault if you follow the POH, if you want to experiment, we’ll there is an Experimental class thst was created for that.

Edited September 30 by A64Pilot

[Pinecone]

The big issue with ethanol in aircraft fuel is due to a very large change in solubility of water when the temp changes.

So you could have a load of fuel with a lot of water suspended in it due to the alcohol.  It is fine when it is warm.  But when it cools at altitude, the water comes out of the solution and with the cold temps, freezes into water slush which can clog the filter screens.