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Politics : Politics of Energy -- Ignore unavailable to you. Want to Upgrade?

To: Brumar89 who wrote (15395)	12/16/2009 9:55:32 PM
From: Eric	Read Replies (2) \| Respond to of 86355

The problem with ethanol is that it is hydroscopic. In other words it absorbs moisture (water). In an aircraft that would be potentially dangerous. I used to fly a Cessna that had an STC to burn autogas (the O200 Continental was designed to run on 80/87 Avgas). The restriction with the ability to burn autogas was that it could not contain ethanol. In a carbureted engine there are times when the mixture of gas combining with the air can be at a temperature where carburetor "Ice" can form thus choking off the carburetor and killing the engine. This temperature band is made much wider by the presence of ethanol and water. Of course this would obviously be dangerous to the passengers this aircraft. Jet engines have problems with burning ethanol because of the complexity of their fuel systems. Not to mention that a gallon of ethanol has a fraction of the BTU's that a gallon of Jet A has. About a year ago a 777 narrowly averted disaster for it's passengers while the jet was on short "final" for Heathrow. The pilots while descending to the runway commanded the engines to throttle up but they died. The plane crashed about 500 yards short of the runway. Fortunately no one died but the aircraft was totalled. Water was found in the fuel heat exchangers that had turned to ice on the long, cold flight from China as they had flown over the N. Pole. When they began their long descent at reduced power the icing became worse but the pilots had no way of knowing. Because of the range of temperatures an aircraft flies through many times the fuel will be "cold soaked" sometimes 30 or more degrees below the freezing point of water. Sometimes even 70 degrees below freezing as was in the case of that long BA777 flight. The FAA currently has an emergency AD on those fuel heat exchangers in those Rolls Royce engines. So far that is the only crash of a 777. A remarkable record considering the 777 has been in service since 1995! If ethanol was not hydroscopic it could be used as a fuel in planes but as any basic chemistry student knows... Ethanol loves water! Simple chemistry Brumar.