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Old Feb 14, 2013, 03:01 AM
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TigreJohn
United States, CA, Corona
Joined Aug 2008
1,073 Posts
I just love reading some of these discussions: castor vs. synthetic, 2 stroke vs. 4 stroke, gasoline vs. methanol. In this particular discussion, in any engine size, gas is more economical to operate for the same sized engine. In terms of power, methanol provides more power in the same sized engine. If you adjust engines sizes in order to match power, gasoline (larger but initially more expensive) is still cheaper than methanol to operate. Take your pick; simplicity with a glow plug and more operating cost; or gasoline with an ignition system and more initial and less operating cost.

Why? Basically, our engines are air pumps. Given two engines of the same size and style: they will both pump (intake) the same amount of air. The difference between them in this example is the amount of fuel needed to burn efficiency and the amount of power in the fuel. Gasoline has 125,000 Btu/gl energy, methanol has 64,600: a 93% advantage. But then factor in air/fuel combustion ratios of 14.7:1 for gasoline; 6.47:1 for methanol: methanol now gains a 17% advantage. Adjust downward for oil content: 5% for gasoline, 17% for methanol. Methanol still has a 3% advantage. Add nitromethane to the mix: all bets are off as to power advantage, but then at the expense of cost.

Jetmech05: FYI, I have a 11# Katana, 71" wingspan, rated for up to a 1.6 ci engine. It has a Super Tigre 2500 (1.5 ci), 16x8 prop, 5% fuel, and it will do what you say it can't do. I have an IMAC pilot who maidened it to verify it.
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