RafaleM_v3.7_FlightModel_Fixes.md

RafaleM_v3.7_FlightModel_Fixes.md

Rafale M v3.7 (Alpha60) — Flight Model & Systems Fixes

Community-made fixes for the freeware Rafale M v3.7 by Alpha60. All edits are plain-text changes to the aircraft's .cfg files — no model or texture changes. Tested in MSFS 2024 (should apply equally to MSFS 2020, since the flight model files are shared).

What you get:

• Working external fuel tank transfer/balancing (broken in stock v3.7)
• Realistic transonic drag — no more casually supersonic at sea level
• Delta-wing energy bleed in sustained high-G turns
• Correct M88-2 dry thrust (stock was ~25% too strong in mil power)
• Autothrottle that can actually hold cruise speed
• Sane fuel-burn figure in the aircraft selection UI

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Before you start

1. Back up these four files (just copy them somewhere safe):
   • SimObjects/Airplanes/Rafale M 3x1275litres/flight_model.cfg
   • SimObjects/Airplanes/Rafale M 3x1275litres/engines.cfg
   • SimObjects/Airplanes/Rafale M 3x1275litres/aircraft.cfg
   • SimObjects/Airplanes/Rafale M 3x1275litres/systems.cfg
2. Use a plain-text editor (Notepad++ etc.). Don't use Word.
3. The sim must be closed while you edit, and you must do the layout.json step at the end or MSFS will silently ignore your edits.

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Fix 1 — Broken external tank fuel transfer

File: flight_model.cfg, in the [FUEL_SYSTEM] section.

Stock v3.7 has two bugs here: the trigger list jumps from Trigger.7 to Trigger.9 (MSFS stops reading numbered entries at a gap, so triggers 9–12 never load), and the Trigger.11 definition is accidentally split across two lines.

Find the four lines starting Trigger.9 =, Trigger.10 =, Trigger.11 = (plus the orphan line below it starting with #Condition:) and Trigger.12 =, and replace all of them with:

Trigger.8 = Name:TransferLeft2#Target:LeftExtTank1,RightExtTank1#Threshold:0.1#Condition:TankImbalanceAbove#EffectTrue:OpenValve.LeftWingTankValve,CloseValve.RightWingTankValve#EffectFalse:OpenValve.LeftWingTankValve,OpenValve.RightWingTankValve
Trigger.9 = Name:TransferRight2#Target:RightExtTank1,LeftExtTank1#Threshold:0.1#Condition:TankImbalanceAbove#EffectTrue:OpenValve.RightWingTankValve,CloseValve.LeftWingTankValve#EffectFalse:OpenValve.RightWingTankValve,OpenValve.LeftWingTankValve
Trigger.10 = Name:TransferLeft3#Target:LeftExtTank2,RightExtTank2#Threshold:0.1#Condition:TankImbalanceAbove#EffectTrue:OpenValve.LeftExtTransferValve,CloseValve.RightExtTransferValve#EffectFalse:OpenValve.LeftExtTransferValve,OpenValve.RightExtTransferValve
Trigger.11 = Name:TransferRight3#Target:RightExtTank2,LeftExtTank2#Threshold:0.1#Condition:TankImbalanceAbove#EffectTrue:OpenValve.RightExtTransferValve,CloseValve.LeftExtTransferValve#EffectFalse:OpenValve.RightExtTransferValve,OpenValve.LeftExtTransferValve

Each Trigger.N must be one single line — make sure your editor didn't wrap them. Triggers 1–7 above these are fine; leave them alone.

Fix 2 — Transonic wave drag

File: flight_model.cfg, in the [AERODYNAMICS] section.

Find this line (stock is effectively all zeros):

drag_coef_zero_lift_mach_tab = 0:0,0.5:0,0.55:0,0.6:0,0.65:0,0.7:0.0034,0.75:0,0.8:0,0.85:0,0.9:0,0.95:0,1:0,1.1:0,1.2:0,1.3:0,1.4:0,1.5:0 

Replace with:

drag_coef_zero_lift_mach_tab = 0:0,0.5:0,0.55:0,0.6:0,0.65:0.0002,0.7:0.0005,0.75:0.0008,0.8:0.0012,0.85:0.002,0.9:0.004,0.95:0.009,1:0.017,1.05:0.022,1.1:0.024,1.2:0.0235,1.3:0.022,1.4:0.021,1.5:0.02,1.6:0.0195,1.8:0.019 ; transonic wave drag rise, peak ~M1.1

Drag now rises from ~M0.85, peaks around M1.1, and eases toward M1.8. The jet still reaches M1.8 at altitude in full burner but has to fight to go supersonic down low, as it should.

Fix 3 — Delta-wing induced drag (energy bleed in turns)

File: flight_model.cfg, in the [AIRPLANE_GEOMETRY] section.

Find:

oswald_efficiency_factor = 0.85 ; Wing Oswald efficiency factor e (non dimensional)

Replace with:

oswald_efficiency_factor = 0.6 ; low-AR delta, gives realistic energy bleed in turns

Fix 4 — Correct M88-2 dry thrust

File: engines.cfg, in the [TURBINEENGINEDATA] section.

Find:

static_thrust = 14000 ; Lbs, max rated static thrust at Sea Level

Replace with:

static_thrust = 11250 ; Lbs - M88-2 dry rating 50 kN (AB tables carry it to ~75 kN)

The real M88-2 makes 50 kN (11,240 lbf) dry; the widely quoted 75 kN is with afterburner. The mod's afterburner tables then land right around the real wet-thrust figure.

Fix 5 — Autothrottle cruise cap

File: systems.cfg, in the [AUTOPILOT] section.

Find:

autothrottle_max_rpm = 70

Replace with:

autothrottle_max_rpm = 90 ; full dry power for AT, kept below afterburner range

Stock 70% couldn't sustain cruise speeds, so speed-hold just sagged. 90 gives the AT full dry power while staying out of burner range (AB engages at 80% throttle position, and an uncapped AT chasing a speed target can cycle the burner on/off — don't set this to 100).

Fix 6 — UI fuel burn figure (cosmetic)

File: aircraft.cfg.

Every one of the 27 livery entries has ui_fuel_burn_rate set to 75 lbs/hr (off by ~two orders of magnitude). Use your editor's find-and-replace — note there are two spacing variants in the file:

• Replace ui_fuel_burn_rate =75 ; with ui_fuel_burn_rate =5500 ;
• Replace ui_fuel_burn_rate = 75 ; with ui_fuel_burn_rate = 5500 ;

Only affects the stats shown in the aircraft selection screen.

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Final step — regenerate layout.json (required!)

MSFS checks every file's size against layout.json and silently ignores files that don't match. If you skip this, none of your edits will do anything.

The mod ships with the standard tool: in the mod's root folder, drag layout.json onto MSFSLayoutGenerator.exe. It rewrites the file sizes and you're done.

Then start the sim (a full restart, not a flight reload) and enjoy.

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Tuning notes

• If mil-power acceleration now feels too sluggish, raise thrust_scalar in the [JET_ENGINE] section of engines.cfg to 1.05–1.10 rather than touching static_thrust.
• If it can't break M1.0 in full burner at sea level, soften the 0.95–1.05 entries in the wave-drag table slightly.
• All values were tuned by feel against real-world figures, not flight-test data — reasonable people can disagree on the exact numbers. The stock values above are quoted exactly, so reverting any single fix is just pasting the old line back (and re-running the layout.json step).

Fixes worked out with Claude Code by reading the mod's config files. All credit for the aircraft itself to Alpha60 (and MartyF909 for liveries). This document describes edits to files you already own — it redistributes nothing from the original package.