Ethanol in airplanes


Good article in this month’s Plane&Pilot on Greg Poe asks the question:

Is ethanol in the future for general aviation? Thought I would ask it here as well…

Greg Poe’s website:

FYI, I’m posting some info on Fagen Inc.'s flight department in the Notable Activity forum, it’s pretty impressive. Lots of aircraft to track.


Ethanol is the highest performance fuel on the market, with an octane rating of 113.

Octane rating has nothing to do with performance; it’s about resistance to detonation.

The big problem with ethanol in aircraft is the reduction in energy density. Who wants to give up 30% of their range? It’s also quite hydrophillic, so it could cause more problems with water contamination.


IMHO (no, I’m not trying to start a flame war) the whole ethanol thing is a farce. If you factor in the reduction of mileage you get using ethanol you end up burning as much extra fuel as you have saved in emissions. It’s a wash, but a political boondoggle.

The corn growers are making a fortune, even though sugar beets will produce THREE TIMES the ethanol as corn (twice the amount if you use sugar cane). But then you couldn’t artificially inflate the price of corn because of the shortage of food corn, could you?

/soapbox off


DARPA (or one of the other DoD research arms) currently has a contract out to 3 companies to produce jet fuel from a non-food bio-feedstock (switchgrass, algae, etc). I think it’s a great idea, since you really don’t want to tie your energy supply to your food supply.


A special interest boondoggle indeed…


Do we know if Teledyne Continental, Textron Lycoming or for that matter Pratt, GE, Honeywell, etc. are testing any “alternative fuel” ideas?

I could look it up, but it’s more interesting to throw it out here…


Now bio-diesel is an entirely different story. It makes a lot of sense. The diesel engine was originally designed to run on peanut oil! One of the theories of Diesel’s mysterious death was that the oil companies were afraid that petroleum based fuel wouldn’t be used.

Rudolf Diesel said, “The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time.”

I wonder if the TwinStar would run on bio?


Agreed. My earlier comment was meant towards Ethanol…which is a joke. Unless of course you’re in the farming industry :unamused:


Looks like I got ahead of myself a bit. Just finished reading the entire August 2007 issue of Plane&Pilot. They devoted the issue to this topic and there are several great articles. One of which talks about a electronic ignition system that GAMI is coming out with this year that will detect any knocking and adjust to eliminate it. Tested on a 350hp Lycoming TIO-540.

In terms of cost to the piston-powered aircraft owner, it seems ethanol conversions would be the least expensive option (based on supply) to replacing leaded avgas. The bio-diesel or alternative Jet A options would require major modifications on potentially thousands of aircraft. New aircraft design will take care of this in years to come, but I think I speak for many owner/operators by saying “What is in it for me?”

Don’t know if this is as much an environmental issue as it is a supply issue. Both important, but which one carries the most realistic solution?


GE Global Research is one of the companies with the contracts from the DARPA program I mentioned in my last post.
GE-Aviation is involved in a project testing alternative fuels with Boeing and Virgin.
I assume the other engine companies you mentioned are also involved in similar projects.




As others have said, ethanol as a way to move to renewable energy and reduce dependence on fossil fuels is an expensive sham that is motivated by the farm looby. The problem with using corn to produce ethanol is that it consumes more energy than it produces (and subsidized to the tune of about $3 Billion annually in the US). Here is one reference:

David Pimentel, a professor of ecology at Cornell University, who has been studying grain alcohol for 20 years, and Tad Patzek, an engineering professor at the University of California, Berkeley, co-wrote a recent report that estimates thatr making ethanol from corn requires 29 percent more fossil energy than the ethanol actually contains.

The two scientists calculated all the fuel inputs for ethanol production - from the diesel fuel for the tractor planting the corn, to the fertilizer put in the field, to the energy needed at the processing plant - and found that ethanol is a net energy loser. According to their calculations, ethanol contains about 76,000 BTU’s per gallon, but producing that ethanol from corn takes about 98,000 BTU’s. For comparison, a gallon of gasoline contains about 116,000 BTU’s per gallon. But making that gallon of gas - from drilling the well, to transportation, through refining - requires around 22,000 BTU’s.


I agree with you fully, CAFlier. For the skeptics, please provide the reference.


I did, but FA was giving me the famous debug error, so had to retype it rather than cut and paste. It is now included in the original post.

I’m not used to agreeing with you Dami, but when you are right you are right.


Get a room you two!