Fuel mixing

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Fuel mixing

Postby Bob Cheshire » Thu Dec 24, 2009 10:21 am

Has anyone got a formula for changing the proportions of components in a given fuel? There is a spreadsheet on the RC boats site but it's password protected which makes it very useful.
Bob Cheshire
 
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Postby loucrane » Sun Jan 03, 2010 12:26 pm

Bob,

You may not need a spreadsheet.

The only ingredients in glow fuel are methanol, nitromethane and oil. The fuels are usually advertised by their nitro content, and occasionally the total oil percentage is alos provided.

Try it this way:

Consider a fuel with 15% nitro and 18% oil. That adds up to 33%, so it has 67% methanol, right?

You can break that down into the fluid ounces (volume measurement) from a gallon, for example. One gallon is 128 fl oz;

15% is 19.2 fl oz (nitro)

18% is 23.04 fl oz (total oil)

If you want to mix a higher percentage nitro fuel with this 15% to get what you want, set your specs. If you the other fuel you'll use has the same oil %, it makes thing easier - the oil % won't change whatever the nitro proportions of the two fuels turn out to be.

You may be able to play withnumbers like these without firing up a spreadsheet. For example - to see what nitro% you get by mixing a half gallon of the 15% with a 40% nitro/same 18% oil fuel.

40% is 51.2 fl oz.

You'll be mixing half of that - 25.6 fl oz - into the new blend. And half the nitro from the origina 15% is 9.6 fl oz.

Total nitro volume then is 35.2 fl oz. Divide by 128 (fl oz/gal) and you get a 27.5% nitro fuel.

Doodling this out however you want is simpler than most spreadsheets I've sen and written for myself.

Any help?
loucrane
 
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