180Marty wrote:All it would take to make 10% ethanol work is the swipe of a pen to make it legal by the FAA--it doesn't take any modification to most planes that can use car gas. I feel pretty confident about that statement.
Marty
Your confidence in that statement is unfounded. If you're an EAA member you can read all their test data on their Web site. My EAA autofuel STC allows for every single additive allowed in the US, EXCEPT Alcohol of any kind. It even allows the use of 82UL, which has no additives.
The problems they found with alcohol blends are all related to it's affinity for water.
1. The alcohol holds water in suspension in the fuel so that it can't be detected, or drained out of the sumps.
2. When the temperature drops, such as during a climb to altitude, the water can suddenly come out of suspension and cause an engine failure. Cars rarely gain 5,000ft altitude in a matter of minutes.
3. If too much water bonded alcohol is present it dramatically lowers the effective octane. They cite an accident report where a float plane refueled at a marina that had been adding Heet to it's tanks instead of draining the water. The aircraft experienced severe detonation shortly after take-off, resulting it holes through all 4 pistons and a fatal crash. Modern cars have knock (detonation) sensors that automatically retard the timing.
The EAA STC does allow up to 1% alcohol, as the above problems didn't start showing up till they reached about 5% alcohol.
Yes, it is possible to safely run alcohol blends in our planes, or even ethanol based fuels. However, it will require storing the fuel in hermetically sealed tanks until used, and draining our tanks after each flight and disposing of the now exposed fuel. We'd also need the flexible, automatic electronic engine controls that cars now have to really make it practical.
Phil