100LL

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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Jim Hardin
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Re: 100LL

Postby Jim Hardin » Fri Jan 04, 2019 1:35 pm

drseti: I know of two gas stations around Lancaster that sell ethanol free gas. That’s where we fill our truck :)

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ShawnM
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Re: 100LL

Postby ShawnM » Fri Jan 04, 2019 6:35 pm

Jim Hardin wrote:drseti: I know of two gas stations around Lancaster that sell ethanol free gas. That’s where we fill our truck :)


I'm sure I posted this before but there is a website, http://www.pure-gas.org that lists ethanol free fuel stations all over the country. Just select your state from the orange box at the bottom of the page and the cities are listed in alphabetical order with the brand and OCT rating and sometimes the cost, which is updated by the users of the website.

They currently list 13,903 gas stations around the country with 3 in Lancaster. There's an app also.

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drseti
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Re: 100LL

Postby drseti » Fri Jan 04, 2019 6:41 pm

Jim Hardin wrote:drseti: I know of two gas stations around Lancaster that sell ethanol free gas. That’s where we fill our truck :)


At 100 miles each way, I couldn't haul enough fuel to make the drive worthwhile.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
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roger lee
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Re: 100LL

Postby roger lee » Sat Jan 05, 2019 9:32 am

If your fuel tanks are okay will 91 oct. with ethanol then there is no real reason not to use it. Your engine and fuel hoses are fine with it. I've been using ethanol fuel in Rotax for 25 years without any issues and so have many others. Many ethanol claims are just myths which are easily proven false.
Roger Lee
Tucson, Az.
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(520) 574-1080 (Home) Try Home First.
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drseti
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Re: 100LL

Postby drseti » Sat Jan 05, 2019 9:40 am

Roger, that's fine if you have actual fuel tanks or bladders. In the case of a wet wing, the upper and lower wing skins are interfaced to front and spars and ribs with a polymer sealant, to form the "tank". It is that polymer that the ethanol attacks, leading to weeping wings - something I only want when I'm de-icing! Then there's the problem of dissolving fuel selector valves and filters. Especially with an SLSA, if the airframe manufacturer doesn't specifically authorize mogas, there's probably a good reason.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US

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JJay
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Re: 100LL

Postby JJay » Sat Jan 05, 2019 12:29 pm

drseti wrote:Roger, that's fine if you have actual fuel tanks or bladders. In the case of a wet wing, the upper and lower wing skins are interfaced to front and spars and ribs with a polymer sealant, to form the "tank". It is that polymer that the ethanol attacks, leading to weeping wings - something I only want when I'm de-icing! Then there's the problem of dissolving fuel selector valves and filters. Especially with an SLSA, if the airframe manufacturer doesn't specifically authorize mogas, there's probably a good reason.


TL Ultralite, the manufacturer of Stings, specifically de-authorizes ethanol in the fuel. No ethanol, ever, because of the issues with the fuel tank.
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2006 Sting Sport SLSA - N686N
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Wm.Ince
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Re: 100LL

Postby Wm.Ince » Sat Jan 05, 2019 1:03 pm

drseti wrote:Roger, that's fine if you have actual fuel tanks or bladders. In the case of a wet wing, the upper and lower wing skins are interfaced to front and spars and ribs with a polymer sealant, to form the "tank". It is that polymer that the ethanol attacks, leading to weeping wings - something I only want when I'm de-icing! Then there's the problem of dissolving fuel selector valves and filters. Especially with an SLSA, if the airframe manufacturer doesn't specifically authorize mogas, there's probably a good reason.

Those are very good points.
Bill Ince
CTSW (E-LSA)
Retired Heavy Equipment Operator

Dave C
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Re: 100LL

Postby Dave C » Tue Nov 19, 2019 6:12 pm

drseti wrote:
FlyAgain wrote:Has anyone just bit the bullet and burning 100LL Avgas in their Rotax engines 100% of the time?


Since ethanol-free mogas is not a available in my state (and I refuse to put solvents into a non-ethanol-approved airframe), I've run two Rotax 912ULS engines now on 100% 100LL, without any issues. I do double up on oil changes and gearbox inspections, but that's it. One made it all the way to TBO without problems, and its current owner continues to operate it on condition. The second one is now halfway to TBO, and I expect it to similarly make it all the way there, and beyond.


Hey Paul,

Sorry that I am so late in joining this conversation as I recently discovered it. My Evektor Sportstar manual does not explicitly mention ethanol. It does state that fuel must be min. AKI 91 and, for the USA, conform to ASTM D4814. What I have been able to gather about ASTM D4814 is that it includes ethanol blends. Does your Sportstar manual say something similar? What is your interpretation?

-Dave

RBearden56
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Re: 100LL

Postby RBearden56 » Thu Nov 28, 2019 1:44 pm

Happy thanksgiving to the Sport Pilot community!

Great discussion on the benefits and problems with ethanol added fuels and use of ethanol free fuels. I asked the manufacture of my Allegro 2000 ELSA about using ethanol free fuels and he told me that I have a fiberglass fuel tank and the chemicals used to boost octane, MEK, react to the resins in the tank, damaging the tank. I did some more research and found the following, "The actual “recipes” for these octane boosters are closely-kept trade secrets, but most of them use one or more or the following ingredients to raise the octane of regular pump gas: methylcyclopentadienyl manganese tricarbonyl (MMT), toluene, and variants of trimethylbenzene. MMT is a common ingredient in lead substitutes as well as unleaded gasoline, while the others are hydrocarbons derived from gasoline production itself. Ethanol is also a popular ingredient in octane boosters, because on its own, ethanol already has a very high octane rating (roughly 110)." I would talk to your aircraft or kit manufacture about the fuel systems ability to tolerate the chemicals used to boost octane ratings in ethanol free fuels. You may be surprised at what you learn. :shock:

'Since ethanol-free mogas is not a available in my state (and I refuse to put solvents into a non-ethanol-approved airframe)' California? What airframe is this? Rotax recommends up to 10% ethanol in the 912ULS and if your plane was designed in Europe, and most LSAs were, I can't imagine a manufacture allowing MOGAS but not ethanol added fuels. No criticism, just curious. The added lead is not good for your engine, you will find lead in your oil, your spark plugs, on your valves and valve seats, crankcase, and oil tank resulting a lot of extra work to keep your engine healthy and I have not heard the same issues using ethanol added fuel, except for long term storage issues, if there are some I would like to know them if used regularly. Fuel system components for the Rotax 912 should be OK with ethanol fuels, but if you use different materials, fuel lines, filters, etc, then you need to make sure they are ethanol and non ethanol fuel compatible.

Hope all have a great holiday!

Randall Bearden
C162 SLSA 3037T
Sport Pilot
LSRM Aircraft

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drseti
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Re: 100LL

Postby drseti » Thu Nov 28, 2019 2:08 pm

Randall, although I lived for many years in CA, I have been in PA for the past 29, and it is here that I can't get ethanol-free. Yes, I know that Rotax authorizes up to 10% ethanol, though they certainly don't recommend it. They also say the airframe manufacturer is the final authority as to whether ethanol is acceptable.

My last two aircraft have been SportStars, with wet wings. That is, the fuel tanks are bounded by the upper and lower skins, first and second ribs, front spar, and rear spar (all sealed to each other with a polymer sealant, with no fuel bladders inserted - same as Mooneys and some Beechcraft). Although the operating instructions and maintenance manuals don't mention ethanol, I contacted the factory, and was told they had not done fuel system testing with ethanol, and thus would not recommend it.

I had a 1970 Beechcraft until 2009. The wings began to leak fuel around 1985, and again around 2000. The first time, the tanks were re-sealed by reaching in thru both the filler cap and the fuel quantity sender mounting plate. The second time, they had to remove the wings and number one rib for access. Expensive - and this was while running 100LL! It would have been far worse with ethanol.

Those aircraft with TIG-welded aluminum box tanks (like the RV-12) and plastic tanks (like the AeroTrek) will probably handle ethanol OK. Maybe even those planes that have a rubber fuel bladder inside the wing. But not my SportStars with their wet wings.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US

RBearden56
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Re: 100LL

Postby RBearden56 » Fri Nov 29, 2019 8:37 am

Paul,

Thank you for your reply, Brian Carpenter, of Rainbow Aviation, published a three part series on 100LL Vs MOGAS in Light Sport Aircraft, Sport Aviation Experimenter, August, September, October 2019. Brian goes into great detail on the advantages and disadvantages of both, including ethanol free MOGAS. They are very informative reading and reiterates the the same things we have talked about here.

I was stationed in CA while in the Air Force, I live in GA now.

I have a wet wing as well and this is an area of interest for me using 100LL. I keep my tanks full and watch for leaks and corrosion.

I appreciate your feedback.

Thank you,
Randall Bearden
C162 3037T
Sport Pilot
LSRM-A


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