About Specific Fuel Consumption of BMS

[ft1676063]

First off, hello to the forum, and thanks all bms team members for bring us your amazing work.

By definition SFC equals to fuel used per hour divide by thrust at that throttle position. Which is
SFC = Fuel / Thrust (either in lb/lbfh or kg/kgfh)
So I made a table below using data ‘copied’ from bms 4.32.

As you look into the table. Some of you guys may find out in MIL thrust at mid/low altitude the SFC is pretty high.
We know that However, turbofan engines are not usually used at MIL or above except for a few scenarios including takeoff, climb , turn etc.
Most of the time in a flight the engines are operated in cruise and does not have that high SFCs.
A typical turbofan engine used on fighter aircraft should have a cruise SFC ranging from 0.75-0.86.

My question is how does BMS emulate this behavior i.e do you use something like ‘linear interpolation’ in the code between IDLE thrust and MIL thrust ?
if that’s true that will introduce a HUGE inaccuracy in terms of fuel consumption.

I hope my English is not so bad so I can describe my question clearly. lol

[Migbuster]

What drag index and weight is your chart for?

The BMS fuel flow calcs look good to me on the few comparisons I have done.

[uri_ba]

fuel consumption is used and it takes speed as well into account.

I’ve never seed the code itself,
but the Fuel Flow in BMS is pretty much inline with the -1 so something is done right

you can use the -1 as reference.