The fuel of the future: Is it already here?

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985.

I recently received a note from reader Scott Shroyer, who is looking to buy a used Cessna 182 with an auto gas STC. He wants to know if it is worth his time to buy the 182 “in hopes of finding auto gas at an airport to fill it up?”

A lot depends on which state Scott lives in as to the availability of auto gas without ethanol. I then forwarded his question to Todd Petersen of Petersen Aviation, who has sold more than 34,000 mogas STCs worldwide since 1983.

Scott’s question raised several questions in my mind. First, is it worth considering the fuel requirement of an engine in the purchase of an aircraft? I would say that it does at this time.

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Ethanol: A very real danger

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil.

In a recent post I discussed the problems with ethanol and water in a plane’s fuel system. I received a large number of replies and most were very positive. However, I did get a number of negative notes. For example, one reader wrote: “Ben Visser, go argue with your wife to get your stupid little victory! I’ve been using ethanol mogas for over 20 years without a drop of water showing up…You’d make a great corrupt politician.”

Two problems here: First is that this guy is definitely not married, because if he were he would know that you never win an argument with your wife. You only think you are ahead sometimes, but you never truly win. The other problem is poor logic. [Read more…]

Unraveling the mysteries of fuel

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985.

Fuel is an item that is very important for the proper operation of our aircraft. Even though the world is full of “fuel experts,” it is still a bit of a mystery.

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How to prepare for the end of 100LL

How should aircraft owners prepare for the switchover from 100LL to its replacement? In a previous post, I stated that if — or when — 100LL goes away, the only fuel that will be universally available for general aviation will be one that is chemically very similar to 100LL, but without the lead, and an octane rating of around 94.

If you have a low compression ratio engine qualified on 80/87 or mid-90 octane fuels, you really do not need to change anything. The only concern is that when the engine is overhauled and broken in on straight unleaded fuel, there maybe a problem with exhaust valve recession. If I owned one of these aircraft, I would wait until 100LL is about to go away and then buy a barrel. [Read more…]

GA’s Catch 22

Why don’t FBOs sell auto fuel? When will unleaded avgas be available — and who will sell it? These questions, and more, abound about aviation’s Catch 22: FBOs will not stock unleaded fuels until the market supports it — and the market will not develop until the fuels are readily available.

A fuel system at an FBO is an expensive thing to install and maintain. Today, it is necessary for FBOs to offer 100LL, as that is the major demand. If an FBO decides to sell a second grade of avgas, then it would need to install a second (or third, if it handles Jet A) fuel tank, filter, pump and related equipment. With all of the requirements for containment, etc., this is a very costly option — and an option that probably will not pay for itself at this time.

If 100LL goes away, leaving only one grade of unleaded avgas, the FBOs will have no use for a second system. There also is the problem of having multiple systems, which increases the chances of misfueling.

As we look into the future, my best guess is that, if we go unleaded, there will only be one grade of unleaded fuel. It would be nice to have multiple grades, but the general aviation market is just too small to economically support more than one grade of avgas.

So what will happen with the new fuels? Basically nothing.  I do not see a significant shift away from 100LL until the government finally says “no more” [Read more…]

Asking for trouble

In college, one of my favorite courses was internal combustion engines taught by Prof. Groves. One semester, the main topic of the course was the differences between spark ignition (SI) and compression ignition (CI) engines. After taking the final test, on which we were to compare the advantages of the SI and CI engines, I stopped to talk to Groves, along with several other students. While we were talking in the hall, another student came up and asked, “What does SI and CI stand for?” I remember Groves just hitting his head against the wall and shaking his head.

I feel this way sometimes when someone asks me, “I was working on my plane recently and did not have any aviation grease, so I used some automotive wheel bearing grease. Is that OK?” Unfortunately, people jump to the conclusion that if it does the same job in an automobile as in an airplane, they should be the same. This logic may or may not work — and if it doesn’t, you can have serious problems.

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