That sticky mess is what I want to eliminate. It runs great on castor etherless, no complaints, but the mess is bad. Synthetic is much cleaner and wipes right off the bench and engine days later, I haven't flown synthetic yet because I wrecked the model.
The modified veggie oil would be fine for me if I made a gallon at a time and used only 10-15% in the fuel. I'd be making oil only once a year or less. It would be worth the hassle if it's cheaper than synthetic and runs as clean in the engine. The only thing that worries me is viscosity. Unless we measure it, we don't know what it is. Straight corn oil is about 5% as viscous as 70W motor oil, and 10% the viscosity of castor. So what does it become after the process?
Blue/black smoke should indicate rich mixture but good combustion. In my estimate our engines are running very rich, quite a way to get to stoich ratios.
I understand energy density. Energy density is a useless term for aircraft as weight is far more important than volume. Fuel is sold by volume so this is important in that regard. That is the primary reason we are using kerosene over methanol. Hydrocarbon fuels in the range of gasoline diesel, and kerosene have, Specific Energy, in imperial units BTU/Lb, varies little. When they fuel an aircraft they talk in terms of pounds of fuel not gallons. Engine efficiency is specified in pounds per HP per hour. Kelly back in post 130 is where you talked about that. Fuel air ratios are specified in mass. Why? The density of air varies with altitude.
Fuel, g/cm^3, BTU/Lb, BTU,Gal
Regular gasoline, 0.735, 18630, 114200
Premium gasoline, 0.755, 18440, 116200
Jet fuel, 0.795, 18420, 122200
Diesel fuel, 0.850, 18330, 130000
The above is from Chevron's website.
How does the energy density come into play in our engines, or any engine for that matter? Energy density is just a characteristic of the fuel. It doesn't change the way it burns. You wanted to use fuel with a lower energy density, and I don't understand why that would be desireable. Your notes on oils in that post don't seem to make sense. The oils that claim to be the cleanest burning have the lowest flashpoints. I'll agree that carb's need to be adjusted for it, but I think we are talking about combustion.
Intersting note at the bottom of this page.
http://en.wikipedia.org/wiki/Detonation