New CT Owner ; Mixing Gas....

[Animosity2k]

So I am ferrying my new to me CT from Coast to Coast at the start of the new month. The current owner has only used pump gas for his period of owning it however he is not sure what the previous owner used. The plane will have pump gas in it when I pick it up and I am now realizing not one of my airports I plan to stop at on the trip home carry pump gas. Will mixing 100LL with whatever pump gas is left in the plane when we land hurt it?

My hanger that I have rented here at home also does not carry pump gas. In fact not one hangar in 50 miles does. Any ideas? I do not own a truck to easily transport 10-15 gallon tanks with me each time I go to the airport. Can I run 100LL and still be ok? Thanks for any input and tips guys! I am super excited.

[Ed Cesnalis]

100LL isn't great.  Over time lead will accumulate and oil change frequency needs to increase.  It does work.  Mixing is not an issue.

[FlyingMonkey]

There is no trouble mixing 100LL and pump gas (mogas).  For the ferry flight distance the lead accumulation will be minimal and don't sweat it.  You can use a lead scavenger like Decalin in the 100LL to reduce lead deposits.

I use 100% mogas when flying locally, but when planning long trips I don't even think about it, and assume I'll be using 100LL.  I'm going to Oshkosh this year and that will be a long trip and probably 20 hours of flight time for the round trip.  I will fill up with mogas before departing, and the rest of the trip will be on 100LL.  No problem at all, I'll just change the oil when I get back.

As for gas at the home airport, I just have four 5 gallon Tuff Jugs that I fill from the gas station down the street from the airport.  My local flights are usually around an hour, which is about one 5 gallon jug of fuel.  If the fuel level is blow about ten gallons, I dump 5 gallons in and go fly. I have to go to the gas station about every 3-4 flights.  A slight hassle, but nothing exasperating.  

I'd like to get a 100 gallon fuel trailer, but if I park that much fuel in the hangar and the airport authority decides to be picky, they will make me remove it.  A bed tank in a pickup truck like Ed has is a pretty good compromise.

[Ed Cesnalis]

9 minutes ago, FlyingMonkey said:

...  A bed tank in a pickup truck like Ed has is a pretty good compromise.

Not a compromise but the best of all solutions.  Standing on my tailgate and filling at 15 gpm from a comfortable position confirms it.

[FlyingMonkey]

7 minutes ago, Ed Cesnalis said:

Not a compromise but the best of all solutions.  Standing on my tailgate and filling at 15 gpm from a comfortable position confirms it.

I dunno, a 100+ gallon tank in the hangar with a hose long enough to reach the fuel tanks sounds best to me.  But it's all personal preference.

[Warmi]

The thing is ... with a 100 gallon tank like that, even with frequent flying it may take more than a month to reach the fuel “at the bottom” ... how do you guard again fuel going bad - especially for ethanol based fuel ?

[Ed Cesnalis]

38 minutes ago, Warmi said:

how do you guard again fuel going bad - especially for ethanol based fuel ?

1st line of defense is to purchase in rough accordance with your plans.  Don't just fill it as a matter of routine.

[FlyingMonkey]

1 hour ago, Warmi said:

The thing is ... with a 100 gallon tank like that, even with frequent flying it may take more than a month to reach the fuel “at the bottom” ... how do you guard again fuel going bad - especially for ethanol based fuel ?

I don't.  Honestly, I have used mogas 3 months old after I recovered from surgery, with zero issues.  It's not something I'm paranoid about.  If the engine starts and runs smoothly, the gas is fine.

[Ed Cesnalis]

Octane loss and phase separation are the things to be aware of

[sandpiper]

Use Stabil in any mogas that will sit around more than a month. Why a month? Don't know. It's a number I plucked out of the air. Definitely on the safe side by a big margin.

[Warmi]

Yeah, the thing that worries me is the octane loss part -  the engine will run seemingly fine but there may be silent detonations going on which will drastically shorten the engine lifespan.

It is basically like running on 87 gas - everything may appear fine but it won’t be in the long term.

Now of course , the real question is how soon a typical gas station mogas will start loosing octane rating - I have never been able to get a straightforward answer to that question - perhaps there isn’t one and the answer is “it depends”

[FlyingMonkey]

You are not going to get noticeable octane loss over 3-4 months.  Let it sit a couple of years, then sure.  I use 93 octane fuel, so I do have a little margin.

[Animosity2k]

If you keep up w/ the maintenance is there any other detrimental affects from running the 100ll? 

[SlingPilot]

I run Mogas locally and 100LL on my cross country’s, if I need to refuel before my return. It’s rare to find a field with MOGAS on the field in my area of operation. That said, I’ve not encountered any problems and tend to change my oil at 25 hour intervals. If I find a period of 90-100% MOGAS use, I’ll go to 50 hours. Sport 4 and ROTAX filters are cheap Enough. 

[Animosity2k]

So I found a airport thats 20NM from my airport where the CT will be hangared. My thought is I can use (2) 5gal containers to make sure I've always got enough fuel to take off and then prior to returning home or starting a long trip I can go there and top off! I guess with having this option so close I really may not have a need to store 14g containers. 

[FlyingMonkey]

30 minutes ago, SlingPilot said:

I run Mogas locally and 100LL on my cross country’s, if I need to refuel before my return. It’s rare to find a field with MOGAS on the field in my area of operation. That said, I’ve not encountered any problems and tend to change my oil at 25 hour intervals. If I find a period of 90-100% MOGAS use, I’ll go to 50 hours. Sport 4 and ROTAX filters are cheap Enough. 

Recommended oil change interval is 50 hours for up to 30% 100LL.  I think if you just using it once in a while and changing oil at 25hrs you are incurring an unnecessary expense.

[FlyingMonkey]

24 minutes ago, Animosity2k said:

So I found a airport thats 20NM from my airport where the CT will be hangared. My thought is I can use (2) 5gal containers to make sure I've always got enough fuel to take off and then prior to returning home or starting a long trip I can go there and top off! I guess with having this option so close I really may not have a need to store 14g containers. 

Mogas on the field is often significantly more expensive than from a gas station.  Also check the octane of the fuel.  

Personally, I'd find flying 20nm, landing, fueling, taxiing, and taking off again every time I wanted to fly a cross country to be a bigger drag then going to a gas station.

[Animosity2k]

25 minutes ago, FlyingMonkey said:

Mogas on the field is often significantly more expensive than from a gas station.  Also check the octane of the fuel.  

Personally, I'd find flying 20nm, landing, fueling, taxiing, and taking off again every time I wanted to fly a cross country to be a bigger drag then going to a gas station.

My gas station only has 93unleaded as the highest octane. Is that what I would want to use?

[Warmi]

91 is the minimum so 93 is obviously good.

Also, if you ever encounter UL94 Avgas that’s pretty much the best fuel for Rotax - basically high octane unleaded avgas.

https://swiftfuels.com/fuel/unleaded-ul94-avgas/

 

[JLang]

3 hours ago, FlyingMonkey said:

You are not going to get noticeable octane loss over 3-4 months.  Let it sit a couple of years, then sure.

Is there a rule of thumb for rate of octane loss over time?  I don't have access to 91+ mogas, so always use 93 octane w/ 10% ethanol from the local gas station.

[andyb]

15 hours ago, FlyingMonkey said:

Recommended oil change interval is 50 hours for up to 30% 100LL.  I think if you just using it once in a while and changing oil at 25hrs you are incurring an unnecessary expense.

The anal side of me had me develop an Excel spreadsheet that keeps track of how much leaded fuel I've consumed, since my last oil change.  It's a more complicated computation than meets the eye, as it's based on what goes through the engine, not what goes into the tanks, which is different. It allows me to assure that I'm not exceeding the 30%.

Attached is my current version.  To use it, first delete what I've filled in on the green cells, then fill them in as you go.  Hopefully it uploaded here ok.

AndyFuel Mix 5 DB.xlsx

[Warmi]

Ok... looking at the excel file , your problem is not avgas vs mogas  but the fact that you are not flying  enough ...:-)

[andyb]

3 hours ago, Warmi said:

Ok... looking at the excel file , your problem is not avgas vs mogas  but the fact that you are not flying  enough ...:-)

You are so very right.  4 grandchildren, local school board president, I flew much more before I retired.  Working on it.

Andy

[tespn]

I built a fuel trailer with a 55 gal DOT approved gasoline tank and that works very nicely.   Before that, I kept a scaffold in the hanger and built a small platform on it roughly 16" above the wing and could siphon in a 5 gallon tank in under 90 seconds with a $8 harbor freight 3/4 shaker siphon.  That worked well, but it was hard to top off tanks completely and filling up cans wasn't as convenient as a one big tank - although much cheaper.  That is a great way to go if you don't want to spend $$$$ on trailer & tank.  Airport would have a hard time hassling you about having a 6' scaffold in the hanger and you can bring fuel to the field as you need it in cans if you don't leave them there.  

When I was looking for ethanol free unleaded the local fuel distributor told me 93 with ethanol starts out as 91 before the ethanol is added and will return to 91 eventually if all the ethanol dissipates.  That takes a long time in a sealed container.  If in doubt run that in your car and buy new.

Lastly, because I avoid 100LL as much as possible, I sometimes carry 2 empty 5 gal cans in the tail of my CTLS and a siphon.  I use a crew car and fill them up. I set them on a towel on the wing and siphon them in (being tall helps).  Empty the cans totally before hauling in the plane; vapor is much more dangerous (explosive) than liquid fuel.  This is a bit of a hassle but I dislike using 100LL.  600hour gearbox inspection & cleanings and reducing TBO by 400 hours is a bigger hassle IMO.

[Animosity2k]

18 hours ago, tespn said:

I built a fuel trailer with a 55 gal DOT approved gasoline tank and that works very nicely.   Before that, I kept a scaffold in the hanger and built a small platform on it roughly 16" above the wing and could siphon in a 5 gallon tank in under 90 seconds with a $8 harbor freight 3/4 shaker siphon.  That worked well, but it was hard to top off tanks completely and filling up cans wasn't as convenient as a one big tank - although much cheaper.  That is a great way to go if you don't want to spend $$$$ on trailer & tank.  Airport would have a hard time hassling you about having a 6' scaffold in the hanger and you can bring fuel to the field as you need it in cans if you don't leave them there.  

When I was looking for ethanol free unleaded the local fuel distributor told me 93 with ethanol starts out as 91 before the ethanol is added and will return to 91 eventually if all the ethanol dissipates.  That takes a long time in a sealed container.  If in doubt run that in your car and buy new.

Lastly, because I avoid 100LL as much as possible, I sometimes carry 2 empty 5 gal cans in the tail of my CTLS and a siphon.  I use a crew car and fill them up. I set them on a towel on the wing and siphon them in (being tall helps).  Empty the cans totally before hauling in the plane; vapor is much more dangerous (explosive) than liquid fuel.  This is a bit of a hassle but I dislike using 100LL.  600hour gearbox inspection & cleanings and reducing TBO by 400 hours is a bigger hassle IMO.

Why do you need to siphon the fuel tanks into the wing? Can you not just tip them and put the gas tank nozzle in the fill hole on the wing? What am I missing as EVERYONE mentions siphoning....