Comment

Comment by Stephen R. Smith on November 14, 2010 at 10:21pm

My thanks to those who have read and commented on this post. As in all things aviation there are opinions and things to consider. The dialogs we have amongst ourselves can move us closer to the facts so we can make informed decisions. Aviation is risky business. In the past two years my EAA chapter has lost 3 pilots in crashes. A neighboring EAA chapter has one pilot in the hospital (intensive care) with nasty injuries and one at home with a broken leg right now. Understanding our planes, there limits and ours is important.

Regarding the safety of using plastic tanks to transport fuel: All I can say is that’s how it’s done. Plastic gas tanks are everywhere. Why is fueling an airplane different then fueling a motorcycle, lawnmower, garden tractor, ATV, waverunner or a boat? I have been handling plastic gas cans for years – haven blown anything up yet. Keep in mind that most of the pumps we use to dispense 100LL push the fuel out at a terrific rate. I can see why that could create static – grounding the plane is a good thing. In contrast, the fuel comes out the hose on the plastic tanks I use quite slowly. I fuel my plane in the hanger out of the wind. The tanks I use remain closed except for the small air vent. The fuel drains down the hose right into the plane’s tank. The hose is resting on the bottom of the tank and is generally submerged in fuel. I think the risk of a spark setting off the fuel is quite low with this arrangement. Frankly there is a greater risk of spilling or overfilling the plane if one gets distracted. It is best to only buy what you know will fit in the plane’s tank or keep a close watch so you don’t end up with a fuel spill. I wonder why I know about that…

I have done some reading on the subject of ethanol in fuel and, as has been pointed out, there are indeed issues. When it comes to ethanol in fuel, the boating industry faces many of the same issues the aviation industry does; extended down times with the chance of fuel getting old and “going bad”; fuel tanks vented directly to outside air allowing moisture to enter the tank with daily temperature change; hard-working engines that are intolerant of lower than expected octane. The boating industry uses relatively inexpensive fuel additives to combat these issues. The most widely used additive seems to be STA-BIL marine formula. Folks seem to swear by it.

It would seem buying fuel from a reliable source is important. I get my fuel from a high-traffic, well regarded name-brand station. The station is only 40 miles from the refinery that supplies it. There is every reason to believe the fuel is fresh and good quality. In any case, in my 40 years of driving a car I have NEVER had a fuel problem.

Keeping a fuel tank full reduces the amount of daily “breathing” the tank will do with daily temperature change. This will reduce the amount of moisture that will come in contact with the ethanol.

Besides using a credible fuel additive like STA-BIL, those of us with two fuel tanks (unlike the poor folks with RV12s) have another option. Put a few gallons of 100LL in the pilot’s tank and put automotive fuel in the passenger’s tank. Use the 100LL to taxi out and climb. Use the automotive fuel in cruse then switch back to 100LL to land and taxi back in. This will keep the ethanol out of contact with most of the fuel system when the plane is at rest. There are 8,760 hours in a year. How many hours do you fly per year? Try as I might, I can only get in about 230 hours per year. That’s only 3% of the “available” time. It’s hard to see how that would damage a carburetor.

By the way, I only check for water in my gascolator every few months – gasp! I have never found ANY water in the fuel drained from the gascolator on my plane even though I have been using ethanol-laden fuel for months now. Perhaps that is because my plane is always hangered when at home. When it does spend the night outside in the rain it still does not end up with water in the fuel. Having properly adjusted gas caps helps with this, I am sure. (Tighten the nut on the fuel cap’s underside as much as possible while still being able to turn to close.)

Steve

Comment by Bob Pustell on November 11, 2010 at 11:41pm

I will add my nervous nellie comment. So far you have found two things that the ethanol damages, the fuel caps and the Bing carb floats. Hopefully, you will not discover another vulnerable critical component by having a power failure and/or an accident. And yes, you can (and will) corrode aluminum with ethanol based fuel. It is called phase seperation and it creates corrossive agents that love to eat aluminum. The fuel tanks are aluminum. The carb is aluminum. I believe the body of the fuel selector and gascolator are aluminum. Some of the fuel lines and fuel system fittings are aluminum in some airplanes. Hmmmm.

I have been told by experts that the only way to safely use ethanol fuel is to ALWAYS have fresh fuel in the system. If you do not burn it within a day or two of putting it into the plane, it has to come out. ALL of it has to come out, including what is in the fuel lines and the carb body. The problem is when it ages a bit it pulls moisture out of the air and (possibly) phase seperates and becomes nasty.

Modern automobiles do not have a phase seperation problem because the fuel system is sealed, it breathes through the emissions system. No access to the atmosphere, no intake of water. Old cars and all airplanes have fuel tanks that vent directly to the outside world so the fuel is alway exposed to our humidity laden atmosphere and the alchohol in the fuel greedily sucks up that moisture until it saturates. Then the phase seperation and corrossion begins. Lawn movers and chain saws and such have this problem, also. My friend with a small engine repair shop has been doing a lot of work lately.

One is not guaranteed to get phase seperation with older ethanol fuel, but one is not assured of NOT having it, either. It is a calculated risk with a lot of unknown variables.

Comment by Jim Belcher on November 11, 2010 at 5:31pm

The person starting this blog did not go into detail about plastic cans, but at least one responder mentioned it. This is probably not going to be popular, but.... not only can you not ground plastic gas cans, you can't ground fuel. Neither conduct electricity. That's part of why capacitive fuel gauges work: the gas acts as a dielectric.

All you can ever do to keep static electricity from allowing the gas to explode is to transport in in a metal can, and transfer it through a hose surrounded with metal, all of which are connected to the airframe, and earth ground. You can surround the gas with a grounded shield and prevent static electricity, but you can't ground the gasoline. Running gas through a typical plastic surface has a risk of stripping outer shell electrons from the gas and the plastic, much like rubbing a cat's fur, and also generating static.

It's a free country, and you can transport gas and transfer it however you wish. However, please be aware of the danger.

That's my 25 cents worth, reminding everyone as always that 25 cents won't buy what it once would. :)

Comment by Stephen R. Smith on November 11, 2010 at 12:44pm

Hello Mack,

I am reasonably sure all gas sold for cars in California contains ethanol. Ethanol is the replacement for MTBE which was previously added to gas to "oxygenate". MTBE is carcinogenic.

It may be that Ethanol will corrode some fuel system parts. I am saving enough money to replace the entire carb from time to time if necessary; probably not going to be.

Steve

Comment by Mack P. Kreizenbeck on November 10, 2010 at 8:03pm

Steve,
I'm going to Costco!
You said something about changing the floats ought to cure the problem of alcohol damage.
This sounds good up to a point as I understand the Bings can be damaged (pitted) internally by allowing ethanol to sit in the bowls for any period of time. I picked this info up from a motorcycle group. Maybe some more research is needed to verify!! Phillips 66, here in Idaho, advertises "no alcohol" in their fuels. Do you have any 66s in California?
Keep up the good work,
Mack

Comment by Dr. Edward M. Moody II on November 8, 2010 at 10:04am

I have a local source for ethanol free auto gas through one of my EAA chapter members. That's all I use now.... it's 93 pump octane or about 96 - 97 RON and I have had no problems with it at all. Early on, for the first 35 - 45 hours I bought local Murphy gas station premium gas and honestly, I wasn't seeing any problems with that either but decided that avoiding ethanol completely AND getting the fuel delivered to my hangar in bulk (I have a 200 gallon steel fuel storage tank and pump in the hangar) was way too convenient to turn down. It ends up costing me 10 - 15 cents per gallon more than Murphy prices but I just don't get to fly enough to hurt my budget at that cost.

Ed

Comment by John Ellis on November 8, 2010 at 6:42am

I use 93 octane auto fuel regularly since I run a Soob auto conversion. It has ethanol in it so I'm careful with the carb heat and have not had any trouble (yet). The major advantage to the higher octane is slower burn and less chance of detonation if it is running lean. I can't remember if bing carbs are altitude compensated. If not, you may want to be careful at higher density altitudes when running lower octane. Another consideration is that octane dissipates over time, so an 87 left in the wing can be much lower if not used.

I too use plastic cans but now use a ground strap. The plastic can pick up quite a charge just with air blowing across it. Sitting on a painted wing does not provide a good ground path, not like the filler hole. You may want to ground the cans to a clean surface. There are many documented incidents related to static and ungrounded plastic cans burning up airplanes.

John

Comment by Louis W. Ott on November 7, 2010 at 11:28pm

There are quite a few locations where you can get unleaded gasoline without ethanol. Here is a web site you can check. Click on the list of states to check availability in your state. Some of the octane listings are wrong so double check the octane at the station.

http://pure-gas.org/index.jsp?stateprov=OR