Engine Perf: no air density based fuel consumption and cruise N1/N2% are too low

[picklertune]

I found the fuel consumption 'behavior' and engine performance N1% levels are inaccurate.

Due to lower levels of oxygen density, fuel consumption should be much higher at lower altitudes at the same thrust levels (N1%). To address the fuel flow problem, I added use_old_fuelflow_simvar=1 along with TSFC of 0.5 to simulate air density based fuel flow. this yields about 9,000 lbs of fuel flow (per engine) at 40,000 FT, and 32,000lbs of fuel flow at 3,000 FT at full thrust.

Also the engine N1% is too low during cruise at high altitudes - i observed around ~70%. Therefore I modified the "n1_and_mach_on_thrust_table" to increase N1% levels during Mach flight. This has increased N1% about 10-15% at mach cruise.

Now I'm not sure if the full fuel flow of 7,500lbs and 32,000lbs are real world numbers as I did not modify the high/max fuel flow values (these should theoretically have no effect on fuel flow, it should be thrust and thrust specific fuel consumption). However at Mach 0.85 and cruise level of 35k FT, i observe 7500lbs of fuel flow and 85% N1 per hour per engine with a full load, which seems accurate. Perhaps someone with real world numbers can tweak the flow numbers. I have increased the thrust scalar to 1 to compensate for more realistic N1 Mach thrust levels and slightly reduced the dry thrust. However again this can be tweaked if Mach climb is problematic. I believe in the real world, a fully loaded 787 should climb from 24k FT to TOC at Mach 0.79 and 1000-1,500 FPM max:
https://contentzone.eurocontrol.int/aircraftperformance/details.aspx?ICAO=B788

engines.zip
.

[nakajimayoshi]

Hi there,

The source you link references the B787-8 which has a different performance profile than the B787-10 (Which the Heavy Division mod is based off of)

We appreciate the effort to contribute to the mod, but the addition/changing of files must be done in the Pull Request section. This makes it easier to review code and ensure proper testing has been done by the Pull Requester.

Let me know if you need help setting up a pull request.