Use of Alternate Fuels in Light Aircraft

Light aircraft are older, simpler technologies than modern cars, and thus easier to convert to utilize alternative liquid fuels. The specific differences between aircraft and automotive technologies impacts the choice of conversion approach. Fuels of technological interest include alcohols, ethers, and blends of these with gasolines or each other, but ethanol appears to be the preferred choice. Conversion must address metering, compatibility, timing, cold start, intake icing, and the delivery of increased fuel flow rates. Routine alternate fuels use implies that blends will be flown during the transition period from aviation gasoline to the new fuel. The two most important issues that must be addressed for safety of flight with gasoline-ethanol blends are moisture-induced phase separation and vapor lock behavior. Fuel density and handling characteristics appear not to be a problem. Research to date demonstrates that there are no real problems and many benefits when operating aircraft on ethanol fuel, and that there are no problems operating an ethanol-converted airplane on aviation gasoline. Research into the issues and operating characteristics of flying ethanol-gasoline blends is underway.