So if I use the BSFC model, to figure HP.. If I fly around and burn 4 gal per hour .
BSFC .50 / 6.25 = .0800 gallons / horsepower / hour.

50 x .0800 = 4 Gal per hour.. so I am cruising around on an average of 50 hp. (?)



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Brake-Specific Fuel Consumption

To start the calculations for fuel consumption we use the BSFC (Brake-Specific Fuel Consumption) for the fuel being used. BSFC measures the amount of fuel needed per horsepower per hour. Fuel is measured in pounds instead of gallons.


Listed below are the BSFC ranges for average efficiency Gas, E85 & Methanol engines at their peak hp output. An engine's BSFC can vary depending on load and RPM, these rates aim to represent the peak horsepower environment. The unit of measure here is lbs / hp / hr.

Gasoline .45 - .50
E85 .63 - .70
Methanol .90 - 1.0

You can used these BSFC values to calculate the fuel requirements for various horsepower levels. The above BSFC number tell us that our gasoline engine requires .50 lb of fuel per horsepower per hour. Said another way, we know for each horsepower our gas engine creates we will need .50 lbs of fuel per hour. Expressed as a formula it looks like this:

Given Horsepower x .50 lb fuel/hp = lbs of fuel for given horsepower

To calculate Fuel Consumption for a 400 hp Gas engine with a BSFC of .50 lbs/hp/hr:

400 hp x .50 = 200 lbs/hr

To convert this lbs/hr to a more meaningful gallons per hour we use the conversion rate from lbs to gallons which is 6.25 lbs to 1 gallon of gas

200 lbs/hr / 6.25 lbs/gal = 32 gph

And that's it! Now you have an approximate peak gph fuel requirement for your engine that can guide you in choosing your fuel system components.

If you will be doing this calculation often, you can make it even easier by converting the BSFC you prefer for your fuel from the normal lbs/hp/hr unit of measure to a gal/hp/hr measure. This way you will only need to multiply your horsepower by that figure to arrive at your GPH rate, without the need for converting from lbs to gallons after.

BSFC .50 / 6.25 = .0800 gallons / horsepower / hour.

Again we calculate Fuel Consumption for a 400 hp Gas engine.

400 hp x .0800 = 32 gph


http://blog.cantonracingproducts.com/bl ... _fuel_flow

Now my head hurts.

That's why I had to look it up.....I wasn't going to figure that out by myself.....

It doesn’t appear to take into account engine efficiency.
A 400hp engine nowadays uses nearly half the fuel/hr than a 400hp engine from 50 yrs ago (Eg ford Windsor’s and Cleavlands)
Or am I missing something here?