Whatever happened to...

[cRiPpLe_rOoStEr]

Originally Posted by Piotrsko

I was under the impression that per seat mile, fuel consumption of modern aircraft high bypass engines was competitive to cars. 747 aircraft claimed 20seat mpg with 40 year old engines.

I remember seeing reports claiming an even better seat MPG for them.

Having a STC for auto fuel in my 50 Piper Pacer, preignition was the most detrimental hazard followed by alcohol eating the rubber hoses. The difficulty with auto fuel is the variable octane batch to batch and the mass of odd chemicals added to the base fuel all of which is not posted on the pump. With a $30,000 USD replacement cost, you get careful really fast.

Besides getting the STC, doing an overhaul of the entire fuel system is a desirable preventive measure. When it comes to variable octane batch to batch, sometimes there is an increase on the lead content of AvGas in order to keep the octane rating constant batch to batch. I'd much rather trust on ethanol.