Fuel consumption 737 Max 8

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ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

Hi everybody,

Excellent work of Rikoooo for the v1.03 Boeing 737 Max 8, but after several flights, fuel consumption is very low and far away from real numbers.
So far I'm getting an average as low as 6.020 pounds/Hr at cruise level (FL370 @ 0,79M). Has anyone come up with a solution?
In other models, I have made changes to variables:

fuel_flow_scalar
ThrustSpecificFuelConsumption

But I don't mean to make any changes over the good work of Rikoooo team, risking maybe to get some CRC error, making the model not working anymore.

Any advice would be appreciated, thanks

Nicola
PAUL1984
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Fuel consumption 737 Max 8

Unread post by PAUL1984 »

Try replacing the parts in your Aircraft.cfg located (for example C:Program FilesMicrosoft GamesMicrosoft Flight Simulator XSimObjectsAirplanesBoeing 737-MAX8 Multi-Livery)
with these parts IF they are different.

[GeneralEngineData]
engine_type = 1
Engine.0 = -48.88, -16.66, 0
Engine.1 = -48.88, 16.66, 0
fuel_flow_scalar = 0.667 //ORIG .785
min_throttle_limit = -0.25

[TurbineEngineData]
//CFM LEAP 1B
bypass_ratio = 9
fuel_flow_gain = 0.004
inlet_area = 17.5
rated_N2_rpm = 15000
static_thrust = 26500
afterburner_available = 0
reverser_available = 1

Hope i've helped.

Paul
ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

Hi Paul,

Your lines are ok, are the same that you can find on the original aircraft.cfg. A couple of days ago I've made myself a little mod to the file just to check, and I as suspected, there is a security check (CRC or something like) from the author in order to do not change anything. I just changed "fuel_flow_scalar" to a value that I realized by myself, but the package then won't load at FSX start. So I put back the original file to have pack loaded again.

The situation is that the current values are giving a very low fuel consumption (you can fly around the world with 100% block fuel), and I like very much to "fly" considering fuel/time records. Very nice work from Rikoooo, just some adjustments needed to have an almost perfect work. Hope the authors will do it sometime or maybe will let us (users) accomplish changes in order to get more real values.

Thanks for your suggestion !!
Nicola
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touille451
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Fuel consumption 737 Max 8

Unread post by touille451 »

Hi,

Try to change the aircraft.cfg with admin rights.
For me it worked. I changed the fuel flow scalar to 1,68 and now it is much more realistic.
ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

Hi,

Just tried, didn't work, all package has gone again. FSX didn't load the pack.

Thanks for your repply...

Nicola
PAUL1984
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Fuel consumption 737 Max 8

Unread post by PAUL1984 »

Mine worked fine
ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

PAUL1984 & touille451:

Used method of CTRL+SHIFT+ENTER to edit as administrator and worked. Using other procedures did not worked.
I will try with a couple of flights using fuel_flow_scalar=1.68 and will report results.

Thanks again !!
Nicola
ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

Hi again,

Made some trials using fuel_flow_scalar=1.68 and came up with some results (take a look at the attached pictures):

Taxi consumption: 1.788 p
Climb consumption: 17.098 p/Hr (vs standard 13.750 p/Hr)
Cruise consumption: 4.953 p/Hr (vs standard 5.720 p/Hr)
Descent consumption: 3.154 p/Hr (vs standard 3.295 p/Hr)
ROC: 1.879 fpm
ROD: -1.456 fpm
Trip Fuel Used: 36.168 p (vs 39.732 p planned)
Total Cons: 38.181 p

On the other hand, LittleNavMap came up with this:

Climb consumption: 15.837 p/Hr
Cruise consumption: 4.980 p/Hr
Descent consumption: 3.131 p/Hr
ROC: 1.990 fpm
ROD: -1.464 fpm
Total consumption: 38.179 p

Taxi and Climb consumption rates are high, Cruise and Descent consumptions rates are a little low. Take a look at N1, N2 & FF values at the cruise stage (459 kts @ FL360). It is not simple to put aircraft to do it the right way. But I will keep going, of course, I need much more knowledge regarding the math model for consumption and its relationship with the aircraft.cfg variables (e.g.: bypass_ratio, fuel_flow_gain, rated_N2_rpm, ThrustSpecificFuelConsumption, etc...)

I read the MS help at--> https://docs.microsoft.com/en-us/previo ... dfrom=MSDN
but still very confused, I'll keep going...

If anyone has some more information regarding modeling consumptions would be appreciated.

Regards,

Nicola
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amberdog1
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Fuel consumption 737 Max 8

Unread post by amberdog1 »

I opened the .cfg file as a text file, made the changes then saved it as a cfg, made a back up of the original file and did a copy and paste the new one. It worked, and now my plane also have a more realistic fuel compsumption. I never thought to adjust the cfg on it.
Thanks for posting this thread.
AD
Happy Flying
ndiscenza
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Fuel consumption 737 Max 8

Unread post by ndiscenza »

Hi, yes amberdog1

It works fine, PAUL1984 posted a value of 1,68; and "final" consumption is very near the standard.
You can try other values, with 3 digits included (1,678 or 1,682), and you'll get very good results depending flight procedure.

The only matter is that Climb consumption is too high, and Cruise and Descent consumptions are a "little" low.
I'm still looking for a good "relation/ratio", but it is needed more knowledge regarding other values on the .cfg for Engine and Thrust and its relationship between them. If it happens that you find information please post us here !!

Regards,

Nicola
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