Tony - Even full aircraft can be modified for ethanol use. Our fleet was donated or purchased aicraft. We simply pull what components we needed and anodized the alluminum, and replaced natural rubber with teflon.
- The water issue is another reason we did the test. Ethanol is moonshine, and readily absorbs water. Now, you will never get 100% ethanol outside of a labratory. Even your 200 proof moonshine is roughly 95% ethanol and 5% water. Part of our testing included static tank test, aka fuel sitting in the tank for extended periods of time without use or agitation. The highest water absorbtion we saw was 5% during a hot, rainy Texas summer. Since the ethanol distributes the water, you don't have to worry about water destroying your fuel tank or vapor locking the engine. Our tested used E85 (85% ethanol 15% denaturing chemicals). We then added water (at 5% incriments) into the fuel tank and ran the engine for 5 hours, mimicing all phases of flight. We did go up to 15% water before we started hitting peak EGT before backing off on the throttle. In short, your fuel tank isn't going to allow enough water vapor in the air to pass into the tank and be absorbed to the point of causing noticeable changes. If there is that much water, someone poured it into the tank. Chris - E85/E90 is what we considered 100% during our testing, because it was 100% ethanol fuel with no 100LL in the tanks. Fuel manufacturers are required by law to add denaturing chemicals to the ethanol fuel so you can't give your car/airplane a gallon and a gallon for yourself. - In all my testing and the research that had been previously done, I couldn't find anything connecting vapor lock with ethanol use. I will state, we did have issues with start up in extremely cold temperatures (subzero Farenheit), which was countered with a fuel heater. So, probably not a great fuel for Alaskan winters. - For corrosion, we did multiple test to include common aircraft metals and composite materials. Ethanol does a great job cleaning steel (our 5,000gal steel fuel cell had no corrosion when inspected at the 5 year mark. It even cleaned the rust off of a chain that was dropped into the tank.). It does eat alluminum, but anodizing protects the alluminum components. We slosh anodized our Cessna tanks and saw no problems. With the composites, we used E-glass and Aeropoxy resin, gel coat, and carbon fiber. We saw no reaction to any composite materials during the 5 year testing. Bill - Most auto "flex fuels" are tuned to run on 87 octane, which further drives people away. NASCAR and INDY do run ethanol due to it's benefits. It also makes fuel spill clean up a lot easier. E90 and E85 are becoming more popular, but if you are in an area that has either, you could use it. One of the reasons for our testing between different ethanol and 100LL testing was for availability reasons. Say someone is able to fly at their home airport on ethanol, but was not able to find it during a cross country. You wouldn't know the exact ratio. So we tested at 10% incriments betwen 100% ethanol fuel (E85) to 100% 100LL. There were no changes in performance, outside of what we expected due to fuel flow and horsepower changes that happen between the fuels.
