## FLIGHT MODEL CONFIG DEFINITION

The flight_model.cfg file is an optional aircraft file for defining the flight model of the aircraft. In general, you'll want to prepare this file using the DevMode tools (see here for more information) and then tweak the values if required in the CFG file.

Below you can find information on the different sections used in the flight_model.cfg file as well as what parameters and values are expected within them. You can also find an in-depth explanation of the physics behind the flight model from the following page:

NOTE: To help with the configuration of the Flight Model (and the Engine Config Definition) we have included an *.xlsx file with the documentation that can be used to generate the required values for many of the parameters based on a small number of inputs (these inputs are marked in blue in the file): PlanePerformanceSpreadsheet.xlsx

### [VERSION]

The  [VERSION] section provides version information for the configuration file. In Microsoft Flight Simulator, major versions should always be at least equal to 1. Note that this section information is mandatory and should always be included.

Parameter Description Type Required
major Major CFG file version number, values must be greater than 0. Integer Yes
minor Minor CFG file version number, values must be greater than 0. Integer Yes

### [WEIGHT_AND_BALANCE]

This section is used to define the weight and balance of the aircraft. Most position parameters in this section are given relative to the Datum Reference Point for the aircraft, which is itself specified in this section. The convention for positions is that a positive value equals forward, to the right, or vertically upward, and note that all units are in ft, unless mentioned otherwise. Any 3D coordinates are given with respect to this referential in the following order:

• z (longitudinal) coordinate
• x (lateral) coordinate
• y (vertical) coordinate

The only parameters that are not relative to the datum reference are the parameters for the manual longitudinal positioning of the CoL, compute_aero_center and aero_center_lift.

The available parameters for this section are:

Parameter Description Type Required
max_gross_weight The maximum total weight of the aircraft when fully loaded, in lbs. Float Yes
empty_weight The empty weight of the aircraft, in lbs. Float
reference_datum_position The position of the Datum Reference Point relative to the model center. A three value list - z, x, y - with values in ft.

1D Table of 3 Floats

empty_weight_CG_position The position of airplane empty weight CG relative to the Datum Reference Point. A three value list - z, x, y - with values in ft.

1D Table of 3 Floats

CG_forward_limit Forward limit of the CG as a Percent Over 100. For example, 0.11 is equal to 11%MAC. Float
CG_aft_limit Aft limit of the CG as a Percent Over 100. For example, 0.4 is equal to 40%MAC. Float
empty_weight_pitch_MOI The empty pitch MOI, in Slug sqft. Float
empty_weight_roll_MOI The empty roll MOI, in Slug sqft. Float
empty_weight_yaw_MOI The empty yaw MOI, in Slug sqft. Float
empty_weight_coupled_MOI The empty transverse MOI, in Slug sqft. Float
activate_mach_limit_based_on_cg

When set to TRUE (1) this activates mach limitation depending on CG position.

Default for most aircraft is FALSE (0).

Bool
activate_cg_limit_based_on_mach

When set to TRUE (1) this activate CG limitation depending on the mach value.

Default for most aircraft is FALSE (0).

Bool
max_number_of_stations The maximum number of payload stations.  Integer
station_load.N

This parameter can be used multiple times to define each of the payload stations up to the maximum defined by the max_number_of_stations value (note that counting starts at 0, so for 15 stations N would be from 0 to 14). Parameter takes a comma separated list with the following format:

weight, x, y, z, name, type

The weight is in lbs, (x, y, z) is offset from the reference datum and in ft, the name is a localisable string, and the type can be one of the following integer values:

- 0 (Unknown)
- 1 (Pilot)
- 2 (Copilot)
- 3 (Passenger)
- 4 (Front Pax)
- 5 (Rear Pax)
- 6 (Baggage)

1D Table of 6 Values

No
(Unless max_number_of_stations is greater than 0)
station_name.N

This parameter defines a name that will be used in the payload dialog, and has a 15 character limit. Omission of this will result in a generic station name being used. This parameter can be used multiple times to define names for each of the payload stations up to the maximum defined by the max_number_of_stations value (note that counting starts at 0, so for 15 stations N would be from 0 to 14).

String No
(Unless max_number_of_stations is greater than 0)

### [CONTACT_POINTS]

This section is for defining the points on the aircraft body referential frame which are likely to come in contact with the ground. These parameters are used for aircraft positioning on the ground and also for crash simulations. This section has the following parameters:

Parameter Description Type Required
static_pitch The pitch when at rest on the ground, in degrees, where a positive value is "up" and a negative value is "down". Float Yes
static_cg_height The altitude of the CG when at rest on the ground, in ft. Float
tailwheel_lock Sets whether the tailwheel lock is available (TRUE, 1) or not (FALSE, 0). Bool
gear_system_type Sets the gear system type for the aircraft.

Integer:

0 = electrical
1 = hydraulic
2 = pneumatic
3 = manual
4 = none
5 = undefined

emergency_extension_type Sets the type of emergency extension system that can be used.

Integer:

0 = None

1 = Pump

2 = Gravity

3 = Hydraulic backup reserve (Needs [HYDRAULIC_SYSTEM])

gear_locked_on_ground Defines whether or not the landing gear handle is locked to down when the plane is on the ground (TRUE, 1) or not (FALSE, 1). Bool
gear_locked_above_speed Defines the speed at which the landing gear handle becomes locked in the up position, in ft per second. Note that a value of -1 can be used to disable this option. Float
locked_tailwheel_max_range

This defines the maximum angle of the tailwheel when locked, in radians. Default is 0.

Float
max_speed_full_steering Defines the speed under which the full angle of steering is available, in ft per second. Float
max_speed_decreasing_steering Defines the speed above which the angle of steering stops decreasing, in ft per second. Float
min_available_steering_angle_pct Defines the percentage of steering which will always be available even above max_speed_decreasing_steering, in Percent Over 100 Float
max_speed_full_steering_castering Defines the speed under which the full angle of steering is available for free castering wheels, in ft per second. Float
max_speed_decreasing_steering_castering Defines the speed above which the angle of steering stops decreasing for free castering wheels, in ft per second. Float
min_castering_angle Defines the minimum angle a free castering wheel can take (in radians). Float
max_castering_angle Defines the maximum angle a free castering wheel can take (in radians). Float
max_number_of_points The number of contact points for the aircraft. Integer
point.N List of 17 points that defines various parameters related to each contact point. This parameter can be used multiple times to define each of the payload stations up to the maximum defined by the max_number_of_points value (note that counting starts at 0, so for 5 points N would be from 0 to 4). For the actual values required, please see the [CONTACT_POINTS] section on the Additional Config Information page.

17 Value Table of Floats

No
(Unless max_number_of_points is greater than 0)

### [FUEL]

This section is for defining a simplified fuel system that will reflect on the flight model. In general this section is where you'd define fuel systems for basic aircraft, but for more complex aircraft you have the [FUEL_SYSTEM] section which permits you to setup how fuel will be distributed and used within the aircraft on a much more detailed level. Note that only the fuel_type parameter in this section is still relevant for complex aircraft, and all others can be omitted if you have set up the detailed fuel system.

This section has the following parameters:

Parameter Description Type Required
LeftMain

Comma separated list of values that defines the tank. List values are:

z, x, y, total_fuel_capacity, usable_fuel_capacity

(z, x, y) is offset from the reference datum and in ft, and the fuel capacity values are in Gallons. If any tank is not used, simply supply the list with all values set to 0.

1D Table of 5 Values

Yes
RightMain
Center1
Center2
Center3
LeftAux
LeftTip
RightAux
RightTip
External1
External2
fuel_type

The fuel type for the engines.

IMPORTANT! This parameter is the only one from the [FUEL] section that is still required for the modern [FUEL_SYSTEM].

Integer:

1 = OCTANE 100
2 = JET_A
3 = OCTANE 80
4 = AUTO GAS
5 = JET B

Yes
number_of_tank_selectors The number of tank selectors available, between 1 and 4 only. Integer Yes
electric_pump Whether there is an electric pump (TRUE, 1) or not (FALSE, 0). Bool No
engine_driven_pump Whether there is an engine driven pump (TRUE, 1) or not (FALSE, 0). Bool No
manual_transfer_pump Whether there is a manual transfer pump (TRUE, 1) or not (FALSE, 0). Bool No
manual_pump Whether there is a manual pump (TRUE, 1) or not (FALSE, 0). Bool No
anemometer_pump Whether there is an anemometer pump (TRUE, 1) or not (FALSE, 0). Bool No
fuel_dump_rate The fuel dump rate, as a Percent Over 100. Float No
max_pressure_auto_pump The maximum pressure for the auto pump, in psi. Float No
fuel_transfer_pump.N

Defines a fuel transfer pump N, where N starts at 0. Table contents are:

Source, Destination, Rate in lbs/s, Pump ID

Source and Destination are one of the values given here for the different tanks: Fuel Tank Selection. The Pump ID is an integer value used to identify the pump and link it to a circuit.

To toggle the pump on or off you need to first have created a circuit of the type CIRCUIT_FUEL_TRANSFER_PUMP using the circuit.N parameter of the systems.cfg file, and the circuit Type index needs to be the same as the Pump ID.

The pump can then be toggled on/off using the FUEL_TRANSFER_CUSTOM_INDEX_TOGGLE key event, or using the ELECTRICAL_CIRCUIT_TOGGLE key event.

1D Table of 4 Values

No
default_fuel_tank_selector The default fuel selector used in case of autostart, which will override default_fuel_tank_selector.N.

Integer:

1. 0 = Off
2. 1 = All
3. 2 = Left
4. 3 = Right
5. 4 = Left Aux.
6. 5 = Right Aux.
7. 6 = Center 1
8. 7 = Center 2
9. 8 = Center 3
10. 9 = External 1
11. 10 = External 2
12. 11 = Right Tip
13. 12 = Left Tip
14. 13 = Crossfeed
15. 14 = Crossfeed

Left-to-Right
16. 15 = Crossfeed

Right-to-Left
17. 16 = Both
18. 17 = All External
19. 18 = Isolate
20. 19 = Left Main
21. 20 = Right Main
No
default_fuel_tank_selector.N Default fuel selector used in case of autostart for engine N, where N corresponds to an engine (between 1 and 4). This will be ignored if default_fuel_tank_selector is defined. Yes
fuel_tank_priority This is a table of fuel tanks to indicate the order in which they should be used. Dashes can be used to indicate 2 (or more) fuel tanks sharing the same priority

1D Table of 4 Values

No

### [FUEL_SYSTEM]

This section is for defining the aircraft's fuel system in detail. This section is primarily for use in complex aircraft models where the simple [FUEL] system doesn't give enough control or flexibility for the aircraft systems. The parameters within the [FUEL] section should be used for simple aircraft or those that require a basic fuel system setup, or for maintaining old aircraft (like ones imported from FSX). However there is one exception: the fuel_type parameter is required by the detailed fuel system, although all other [FUEL] parameters can be omitted.

This section only has a few parameters, but each parameter can be repeated a number of times if required, where N in the parameter name corresponds to a new item of that parameter type. For example, the Engine parameter can go from Engine.1 to Engine.4 and each one can be defined separately.

At its most basic the fuel system can be thought of as a series of "components" connected by "lines", with the simplest setup being a tank, a fuel line, and an engine. However you can create far more complex fuel system definitions that include multiple components like pumps, junctions, valves, etc... and multiple line connections between them. The system is also dynamic and can be set to respond to certain "trigger" conditions. For example, should a tank become empty, you can trigger an event to close the valve to that tank and open the valve to another tank.

NOTE: You can only connect components to lines and lines to components... You cannot connect two components or two lines together.

These different parts of the system are all setup using the appropriate values within the hash maps required by each of the listed parameters.

IMPORTANT: Connections between the different components are made using the "Name" key in the various hash maps that are associated with each parameter, and so you should try and ensure a clear and consistent naming methodology to help keep the way that the different components connect as clear as possible.

The available fuel system parameters are:

Parameter Description Type Required
APU.N

This defines an APU for the fuel system. You can have multiple APU's per system, numbered from 1 upwards. Details on the APU map contents are given here: APU.N

Hash Map

No
Engine.N

Defines one or more engines (up to a maximum of 4) that form a part of the fuel system. Details on the engine map contents are given here: Engine.N

Tank.N

Defines one or more fuel tanks that form a part of the fuel system. Details on the tank map contents are given here: Tank.N

Line.N

Defines one or more lines that form a part of the fuel system. Details on the line map contents are given here: Line.N

Junction.N

Defines one or more junctions that form a part of the fuel system. Details on the junction map contents are given here: Junction.N

Valve.N

Defines one or more valves that form a part of the fuel system. Details on the valve map contents are given here: Valve.N

Pump.N

Defines one or more fuel pumps that form a part of the fuel system. Details on the pump map contents are given here: Pump.N

Trigger.N Defines one or more triggers that will be used to change components within the fuel system based on certain conditions. Details on the trigger map contents are given here: Trigger.N
Curve.N A 1D table of values. You can define multiple curves for a fuel system, starting at N = 1, and the curves may be used in multiple different parameters. Details on the table contents are given here: Curve.N

1D Table of Values

Yes

NOTE: For all parameters, the "Title" key is localisable, but it is also optional and can be omitted in most cases. Currently only the Tank.N title is visible in the Microsoft Flight Simulator UI.

#### APU.N

This parameter is used to define one or more APU components to be used in the fuel system. This APU is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

APU.N = Name:<apu_name>#Title:<apu_title>#FuelBurnRate:<burn_rate>

Note that you may have more than one APU, in which case you would increment the N index, starting from 1. A typical example of a single APU definition would be like this:

APU.1 = Name:MainAPU#FuelBurnRate:33


Key Value Description Required
Name String The internal name of the APU, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the APU to be displayed in the UI, if applicable. No
FuelBurnRate Float The rate at which fuel will be burnt in Gallons per hour. Yes

#### Engine.N

This parameter is used to define one or more engine components to be used in the fuel system. This engine is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Engine.N = Name:<engine_name>#Title:<engine_title>#Index:<engine_index>

Note that you may have more than one engine, in which case you would increment the N index, starting from 1 and up to a maximum of 4. A typical example of a single engine definition would be like this:

Engine.1 = Name:LeftEngine#Index:1
Engine.2 = Name:RightEngine#Index:2


Key Value Description Required
Name String The internal name of the engine, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the engine to be displayed in the UI, if applicable. No
Index Float The index of the engine this fuel system component refers to. This would normally be the same as the index of the component, but can be different if required.  Yes

The following SimVar is available for this component:

• FUELSYSTEM_ENGINE_PRESSURE

#### Tank.N

This parameter is used to define one or more fuel tank components to be used in the fuel system. This tank is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Tank.N = Name:<tank_name>#Title:<tank_title>#Capacity:<tank_capacity>#UnusableCapacity:<tank_unusable_capacity>#Position:<Z>,<X>,<Y>#InputOnlyLines:<line1_name>,<line2_name>,<etc...>#OutputOnlyLines:<line1_name>,<line2_name>,<etc...>#DropTimer:<tank_timer>#Priority:<tank_priority>

Note that you may have more than one fuel tanks, in which case you would increment the N index, starting from 1. A typical example of a single tank definition would be like this:

Tank.1 = Name:CenterAft
#Capacity:20
#UnusableCapacity:0
#Position:-1.6,-3,-1.5
#Priority:1


Key Value Description Required
Name String The internal name of the tank, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the fuel tank to be displayed in the UI, if applicable. No
Capacity Float The capacity of the fuel tank, in Gallons. Yes
UnusableCapacity Float The part of the total capacity that cannot be used, in Gallons. Yes
Position

List

(3 Floats)

This sets the position of the tank relative to the Datum Reference Point. Value is a comma separated list with the format Z, X, Y, and it is measured in ft. Yes
InputOnlyLines

List

(N Strings)

This is a comma separated list of lines that are to be considered as input only. Lines are given by their name, for example:

InputOnlyLines:Eng1ToTank2,Xfer1ToTank2,Xfer1ToTank2_2

No
OutputOnlyLines

List

(N Strings)

This is a comma separated list of lines that are to be considered as output only. Lines are given by their name, for example:
OutputOnlyLines:TankCenterToCenterTankPump1,TankCenterToCenterTankPump2
No
DropTimer Float Sets the timer that will be started when one of the RELEASE_DROP_TANK_ALLRELEASE_DROP_TANK_1 or RELEASE_DROP_TANK_2 events are called for the tank. This is the time - in seconds - that the user has to validate the jettison command for the tank (only valid for external tanks). No
Priority Integer This controls the order in which fuel tanks are filled (when using the Fuel window), as well as the order they will be used (when skipping in time). The lower the number the higher the priority and tanks with a higher priority will be filled first, and used last. No

The following SimVars are available for this component:

• FUELSYSTEM_TANK_CAPACITY
• FUELSYSTEM_TANK_LEVEL
• FUELSYSTEM_TANK_QUANTITY
• FUELSYSTEM_TANK_TOTAL_QUANTITY
• FUELSYSTEM_TANK_WEIGHT

#### Line.N

This parameter is used to define one or more fuel lines to be used in the fuel system. This line is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Line.N = Name:<line_name>#Title:<line_title>#Source:<source_name>#Destination:<destination_name>#FuelFlowAt1PSI:<psi_value>#Volume:<volume_value>#GravityBasedFuelFlow:<gravity_flow_value>

Note that you may have more than one fuel line, in which case you would increment the N index, starting from 1. A typical example of a single line definition would be like this:

Line.1 = Name:TankRightToRightTankPump1
#Source:RightInner
#Destination:RightInnerTankPump1


Key Value Description Required
Name String The internal name of the fuel line, which is used to reference it in other components. Yes
Title

String

(Localisable)

The title of the fuel line to be displayed in the UI, if applicable. No
Source String A source component name, where fuel will flow from. Yes
Destination String A destination component name, where fuel will flow to. Yes
FuelFlowAt1PSI Float This is used to calculate the effect of pressure on fuel flow. Value is in lbs per second, and if not set will default to 0.1. No
Volume Float This is the maximum amount of fuel that can be in the line at a given time. Value is in Gallons, and if not set will default to 0.24. No
GravityBasedFuelFlow Float This controls how fast the fuel will flow under gravity and also flag the line as being setup in such a way that even without pressure the fuel will naturally flow towards the destination. Value is in Gallon per hour. No

The following SimVars are available for this component:

• FUELSYSTEM_LINE_FUEL_FLOW
• FUELSYSTEM_LINE_FUEL_LEVEL
• FUELSYSTEM_LINE_FUEL_PRESSURE

#### Junction.N

This parameter is used to define one or more junction components to be used in the fuel system. This junction is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Junction.N = Name:<junction_name>:<value>#Title:<junction_title>#Index:<engine_index>

Note that you may have more than one junction, in which case you would increment the N index, starting from 1. A typical example of a single junction definition would be like this:

Junction.1 = Name:FuelSelector
#InputOnlyLines:LeftInnerToFuelSelector,RightInnerToFuelSelector
#OutputOnlyLines:FuelSelectorToPumpsJunction
#Option:LeftInnerToFuelSelector,FuelSelectorToPumpsJunction
#Option:RightInnerToFuelSelector,FuelSelectorToPumpsJunction
#Option:CenterAftToFuelSelector,FuelSelectorToPumpsJunction
#Option:FuelSelectorToPumpsJunction


Key Value Description Required
Name String The internal name of the junction, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the junction to be displayed in the UI, if applicable. No
Option

List

(N strings)

Junctions can have one or more option settings, and each one takes a comma separated list of line names. Lines given for each option will be set to open when the option is set, and all others will be set to closed. The order of definition of each Option corresponds to the index of the option, which is used by the FUELSYSTEM_JUNCTION_SET key event to trigger them. If no options are defined then all connecetd lines will be considered as closed. No
InputOnlyLines

List

(N strings)

This is a comma separated list of lines connected to the junction that are to be considered as input only. Lines are given by their name, for example:
InputOnlyLines:HandPumpValveToEngineJunction, EngineDrivenPumpToEngineJunction
No
OutputOnlyLines

List

(N strings)

This is a comma separated list of lines that are connected to the junction to be considered as output only. Lines are given by their name, for example:
OutputOnlyLines:EngineJunctionToEngine
No

The following SimVar is available for this component:

• FUELSYSTEM_JUNCTION_SETTING

The following key Event is also available:

• FUELSYSTEM_JUNCTION_SET

#### Valve.N

This parameter is used to define one or more valve components to be used in the fuel system. This valve is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Valve.N = Name:<valve_name>#Title:<valve_title>#DestinationLine:<destination_name>#OpeningTime:<time_value>#Circuit:<circuit_index>

Note that you may have more than one valve, in which case you would increment the N index, starting from 1. A typical example of a single valve definition would be like this:

Valve.1 = Name:LeftEngineValve#OpeningTime:3#Circuit:1


Key Value Description Required
Name String The internal name of the valve, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the valve to be displayed in the UI, if applicable. No
DestinationLine

String

The destination line for the valve. If not included, the valve will permit fuel flow in both directions, however if set, then fuel can only flow towards the destination line. No
OpeningTime Float The time, in seconds, that it takes the valve to open/close. Default value is 0.5. No
Circuit

Integer

The index of the electrical circuit that controls the valve. The circuit needs to be of the type FUEL_VALVE (for more information, please see here: [ELECTRICAL] - circuit.N - Type). No

The following SimVars are available for this component:

• FUELSYSTEM_VALVE_OPEN
• FUELSYSTEM_VALVE_SWITCH

The following key Events are also available:

• FUELSYSTEM_VALVE_CLOSE
• FUELSYSTEM_VALVE_OPEN
• FUELSYSTEM_VALVE_SET
• FUELSYSTEM_VALVE_TOGGLE

#### Pump.N

This parameter is used to define one or more fuel pump components to be used in the fuel system. This pump is defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and has the following structure:

Pump.N = Name:<pump_name>#Title:<pump_title>#Pressure:<pressure_value>#PressureCurve:<curve_index>#TankFuelRequired:<tank_name>#DestinationLine:<line_name>#Type:<type_string>#index:<value>#AutoCondition:<engine_psi_threshold>#PressureDecreaseRate:<decrease_value>

Note that you may have more than one fuel pump, in which case you would increment the N index, starting from 1. A typical example of a single pump definition would be like this:

Pump.1 = Name:HandPump
#Pressure:6
#DestinationLine:HandPumpToHandPumpValve
#Type:Manual
#PressureDecreaseRate:0.05


Key Value Description Required
Name String The internal name of the pump, which is used to reference it in other components and fuel lines. Yes
Title

String

(Localisable)

The title of the pump to be displayed in the UI, if applicable. No
Pressure Float This is the pump pressure in psi. Minimum is 0 psi. Yes
PressureCurve

Integer

(Curve Index)

This takes the index N value of a curve defined in the Curve.N section. The curve is the relationship between the percentage of maximum RPM of an engine and the percentage of maximum pressure provided by the pump (the maximum value being defined by the "Pressure" key). This curve is only used when the "Type" key is set to EngineDriven, and it will use the RPM of the engine given in the "Index" key. No
TankFuelRequired String Sets whether the pump requires a fuel tank or not. If a fuel tank name is supplied here, then the pump will automatically shut down when the tank is empty. No
DestinationLine String The line name supplied here sets the direction in which the pump is causing pressure. Yes
Type

String

Sets the type of pump that is being defined. The available strings for this key are:

• Electric - The pump is driven by an electrical circuit. The circuit used is set by the "Index" key.
• APUDriven - The pump is APU driven. Requires that the APU is running and will use fuel.
• EngineDriven - The pump is driven by an engine. The engine to be used is set by the "Index" key.
• Manual - The pump is a manual one and requires user interaction to generate pressure.
• Anemometer - The pump is driven by air input with pressure being based on the velocity of the aircraft. The anemometer to be used is set by the "Index" key.
Yes
Index Integer

An index value that corresponds to the following:

• For electric pumps it is the index of an electrical circuit
• For engine pumps it is the index of the linked engine
• For anemometer pumps it is the index of an anemometer
No
AutoCondition

List

(String, Float)

If this key is included, then you will be able to set the pump to "AUTO" mode, in which case it will only be enabled when the pressure of the fuel reaching the chosen engine goes below a specific threshold. The key requires two values, separated by a comma: the name of the engine to link with the pump, and the threshold value (in psi). No
PressureDecreaseRate Float This key is only required when the "Type" is set to "Manual", and controls how much the pump pressure will decrease per second after the user stops interacting with it. Default value is 0.5 Percent Over 100 (so, a decrease of 50% per second). No

The following SimVars are available for this component:

• FUELSYSTEM_PUMP_ACTIVE
• FUELSYSTEM_PUMP_SWITCH

The following key Events are also available:

• FUELSYSTEM_PUMP_OFF
• FUELSYSTEM_PUMP_ON
• FUELSYSTEM_PUMP_SET
• FUELSYSTEM_PUMP_TOGGLE

#### Trigger.N

This parameter is used to define one or more triggers to be used in the fuel system. Triggers are used to listen for - and react to - specific conditions and events that will affect the way the fuel system operates. Triggers are defined as a hash map comprised of multiple key:value pairs - separated by the # symbol - and have the following structure:

Trigger.N = Name:<trigger_name>#Title:<trigger_title>#Target:<target_name>#Threshold:<value>#:Index:<target_index>#DelayTrue:<seconds_value>:#DelayFalse:<seconds_value>#Condition:<string>#EffectTrue:<effect_list>#EffectFalse:<effect_list>

Note that you may have more than one trigger, in which case you would increment the N index, starting from 1. A basic example of a single trigger definition would be like this:

Trigger.1 = Condition:Autostart_Enabled
#EffectTrue:OpenValve.LeftEngValve,
OpenValve.RightEngValve,
OpenValve.CrossFeedValve,
StartPump.LeftTankPump,
StartPump.RightTankPump


Key Value Description Required
Name String The internal name of the trigger, which is used to reference elsewhere. Yes
Title

String

(Localisable)

The title of the trigger to be displayed in the UI, if applicable. No
Target String The name of a component to target as part of the trigger condition. This key is only necessary when the given Condition requires it. No
Threshold Float The threshold above/below which the trigger is activated. This key is only necessary when the given Condition requires it. No
Index Integer A component Index to target as part of the trigger condition. This key is only necessary when the given Condition requires it. No
DelayTrue Float This is the time - in seconds - that the condition state must remain TRUE before the EffectsTrue key gets triggered. Default value is 0. No
DelayFalse Float This is the time - in seconds - that the condition state must remain FALSE before the EffectsFalse key gets triggered. Default value is 0. No
Condition String The condition that the trigger is checking. See the table in the section on Trigger Conditions And Events below. Yes
EffectTrue

List

(event.name strings)

The effect if the given condition resolves as TRUE. This is a comma separated list of possible condition events combined with the name of the fuel system component that they target. See the section on Trigger Conditions And Events for more information. No
EffectFalse

List

(event.name strings)

The effect if the given condition resolves as FALSE. This is a comma separated list of possible condition events combined with the name of the fuel system component that they target. See the section on Trigger Conditions And Events for more information. No

The following SimVar is available for this component:

• FUELSYSTEM_TRIGGER_STATUS

The following key Events are also available:

• FUELSYSTEM_TRIGGER_OFF
• FUELSYSTEM_TRIGGER_ON
• FUELSYSTEM_TRIGGER_SET
• FUELSYSTEM_TRIGGER_TOGGLE

##### Trigger Conditions And Events

When creating triggers for the fuel system, the hash map has an entry for "Condition". This can be any one of the following strings:

Condition Description
TankQuantityBelow Checks if the tank has a fuel quantity below the given Threshold (threshold in Gallons). Requires the Target key to be a tank name.
TankQuantityAbove Checks if the tank has a fuel quantity above the given Threshold (threshold in Gallons). Requires the Target key to be a tank name.
CGAboveLimit This condition can be used to watch the value of the SimVar CG_PERCENT and then trigger once it goes above the limit set in the Threshold field (as a percentage).
CGBelowLimit This condition can be used to watch the value of the SimVar CG_PERCENT and then trigger once it goes below the limit set in the Threshold field (as a percentage).
Autostart_Enabled Checks if autostart is enabled.
Autoshutdown_Enabled Checks if autoshutdown is enabled.
Manual This is a manual trigger event that can only be triggered by using a Key Event.
TankImbalanceAbove

Checks if there is a relative fuel imbalance between two tanks above the given Threshold (threshold in Gallons). Requires the Target key to hold two tank names, eg:

#Target=TankLeft,TankRight

TankImbalanceBelow

Checks if there is a relative fuel imbalance between two tanks below the given Threshold (threshold in Gallons). Requires the Target key to hold two tank names, eg:

#Target=TankLeft,TankRight

TankAbsImbalanceAbove

Checks if there is an absolute fuel imbalance between two tanks above the given Threshold (threshold in Gallons). Requires the Target key to hold two tank names, eg:

#Target=TankLeft,TankRight

TankAbsImbalanceBelow

Checks if there is an absolute fuel imbalance between two tanks below the given Threshold (threshold in Gallons). Requires the Target key to hold two tank names, eg:

#Target=TankLeft,TankRight

JunctionOptionChanged Requires the Target key to be a junction name, and the Index key to be the Option in the junction to set.

The result of the condition can be checked as either TRUE or FALSE, triggering an "event". These events are defined as a comma separated list in the EffectTrue and EffectFalse keys of the trigger hash map, where each entry in the list is comprised of an event and a target component, for example:

#EffectTrue:<event>.<target_name>, <event>.<target_name>, etc...

The available event types are:

Condition Description
OpenValve Open the named valve.
CloseValve Close the named valve.
StartPump Start the named pump.
StopPump Stop the named pump.
SetJunction Set the named junction to a specific option. When using this event, it requires both a name and an option index, eg: SetJunction.FuelSelector.1
StartTrigger Flag the named trigger to start.
StopTrigger Flag the named trigger to stop.

#### Curve.N

The curve parameter is defined as a 1D table of paired values, and the parameter is appended with a number that corresponds to its unique id (starting at 1). The exact number of paired values that are in the curve will depend on the use the curve is going to get, since curves are used by other parameters to store information. For example, you may have defined a fuel pump like this:

Pump.2 = Name:EngineDrivenPump#Pressure:6#PressureCurve:1#DestinationLine:EngineDrivenPumpToEngineJunction#Type:EngineDriven#Index:1

In this case, PressureCurve:1 references a fuel pressure curve table that would have been defined like this:

Curve.1 = 0:0, 0.2:0.5, 0.62:0.62, 0.88:0.63, 0.98:0.66, 1.0:1.0

### [AIRPLANE_GEOMETRY]

This section is for defining the geometry of an aircraft. The available parameters are:

Parameter Description Type Required
wing_area

Total area of the top surface of the wing from tip-to-tip, in sqft. The wing area impacts the target lift and drag forces. For example it directly impacts lift proportionally to the area:

$L = 0.5 \times p \times v \times v \times WingArea \times C_L$

Float Yes
wing_span

The horizontal distance between the two wing tips, in ft. The wing span impacts the distribution of the forces over the aircraft, and the larger the wing span the greater the increase in the roll and yaw moment of ailerons and also the resistance to the roll movement of the aircraft.

Float Yes
wing_root_chord

Length of the wing Chord at the intersection of the wing and the fuselage, in ft. The chord over the wing will be automatically computed based on the area, the span and the chord at the root. To get a rectangle shaped wing, enter the average chord into the root chord. To get a triangle shaped wing enter a root chord larger than the average chord.

Float Yes
wing_camber The wing Camber, in degrees. Wing camber here means the difference in virtual incidence or slope between the back region of the wing and the front region of the wing. A wing with a lot of camber has a big curve while a wing with less camber is more streamlined. Wing camber mostly has an impact on the pitch moment generated at various wing incidences as well as on the position of the aerodynamic center. Float Yes
wing_thickness_ratio

The wing local thickness, calculated as:

local_chord(x)*wing_thickness_ratio

where:

x = lateral coord

Value is in ft.

Float Yes
wing_dihedral

This is the angle between the wing leading edge and a horizontal line parallel to the ground, as seen when looking at the front of an aircraft. Technically defined as the dihedral angle Lambda, in degrees. The wing dihedral impacts secondary effects such as induced roll and adverse yaw.

Float Yes
wing_incidence

This is the angle (in degrees) the mean wing Chord makes with a horizontal line parallel to the ground, as seen when looking at the side of an aircraft from the wing tip.

This base wing incidence is calculated when the aircraft surfaces are initially "built" in the simulation and before the normalization to the lift table. The base incidence impacts the zero AoA lift and should be set as closely as possible to the real wing incidence so that the normalization has as little work to do in order to reach the target lift polar. The normalization will readjust this incidence in order to match the target lift coefficient.

Float Yes
wing_twist

This is the difference in wing incidence from the root Chord and the tip Chord of the wing (in degrees). Technically defined as the wing twist epsilon.

Most aircraft have twisted wings in order to increase aileron authority close to and during a stall. This also causes higher incidences towards the root of the wing and will cause these regions to stall earlier, which will cause more symmetrical stalls.

Float Yes
oswald_efficiency_factor

The wing Oswald Efficiency Factor (non dimensional) measures the aerodynamic efficiency of the wing, where a theoretically perfect wing will have a factor of 1.0.

This is the "e" in:

$C_{Di} = \frac {(C_L)^2} {pi \times AR \times e}$

While the aspect ratio is defined by the geometry, this factor impacts the induced drag, and most planes have an oswald factor in the order of 0.7.

Float Yes
wing_winglets_flag

Sets whether the aircraft has winglets (TRUE, 1) or not (FALSE, 0).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. Use drag_coef_zero_liftlift_coef_at_drag_zero and induced_drag_scalar to control the target drag polar.

Bool Yes
wing_sweep

The angle of the wing with the lateral axis. This is the angle the leading edge of the wing makes with a horizontal line perpendicular to the fuselage, as seen when looking down on top of an aircraft (expressed in degrees).

Wing sweep has an important impact on secondary effects but also on the location of the wing on the longitudinal axis. The wing will be positioned to align the default 25% aerodynamic centre with the aero_center_lift value and a swept wing will have the root in front of the aerodynamic centre while the tip will be in the back. The wing will be automatically skewed to align with the target aerodynamic centre position.

Float Yes
wing_pos_apex_lon

Longitudinal (z) distance of the wing apex - as measured at the centerline of the aircraft - from the Datum Reference Point point in ft. This distance is measured positive in the forward (aircraft nose) direction. Note that this value will have no effect if the compute_aero_center value is 0 (which is generally how it should be).

Currently not used in Microsoft Flight Simulator.

Float Yes
wing_pos_apex_vert

Vertical (y) distance of the wing apex - as measured at the centerline of the aircraft - from the Datum Reference Point in ft. This distance is measured positive in the "up" direction.

Float Yes
htail_area

Area of the static part of the horizontal stabilizer (not counting the elevator area), in sqft. The horizontal stabilizer and elevator will be simulated as a single wing with surfaces positioned in a way that the overall incidence matches the current control surface deflection. This single surface will have the area of htail_area and elevator_area combined. However, we recommend entering the exact area of each surface. This area will impact the pitch moment caused by the elevator deflection as well as the pitch moment caused by the horizontal stabilizer.

Float Yes
htail_span

The horizontal span of the htail and elevator surface, in ft. A large htail span will impact the roll moment of the propeller wash but also resist the aircraft roll movement.

Float Yes
htail_pos_lon

Longitudinal (z) distance of the horizontal tail apex and elevator surface - as measured at the centerline of the aircraft - from the Datum Reference Point in ft. This distance is measured positive in the forward (aircraft nose) direction.

The longitudinal position of the htail impacts the pitch moment of the htail and elevator surfaces. The htail force vectors should be aligned with the real surface.

Float Yes
htail_pos_vert

Vertical (y) distance of the horizontal tail apex and elevator surface - as measured at the centerline of the aircraft - from the Datum Reference Point in ft. This distance is measured positive in the "up" direction.

Depending on the vertical position of the htail, it can get into turbulences created by the wing located in front of it. In extreme situations this can create a deep and unrecoverable stall.

Float Yes
htail_incidence

The default incidence of the htail and elevator surface combination. This is the angle the mean horizontal tail Chord makes with a horizontal line parallel to the ground, as seen when looking at the side of an aircraft from the horizontal tail tip (in degrees).

The aircraft surfaces will be build with this default incidence setting and all performance normalization will be calculated with this incidence. This means that the target lift and drag coefficients will match the aircraft with this htail_incidence default elevator angle. Any other elevator angle will generate different drag and lift coefficients.

We recommend setting the htail_incidence so that the aircraft flies level at cruise speed without any required elevator input and zero elevator trim. This means that the htail_incidence will be the neutral trim for cruise speed. By doing this the lift and drag coefficients of the aircraft will perfectly match the target values during cruise and the drag force will be the most accurate and match the target performance during cruise. This also means that during any other phase, the drag performance of the aircraft won't perfectly match the target formula because of the added drag caused by the added elevator deflection required to maintain a level flight at any other speed.  This target formula is expressed as:

${C_D} = {C_{D0}} + K(C_L - C_{L0})^{2}$

However, it is possible to chose a different speed than cruise and set the htail_incidence for that speed.

Yes
htail_sweep This is the angle the horizontal tail leading edge makes with a horizontal line perpendicular to the fuselage, as seen when looking down on top of an aircraft (in degrees). Float Yes
htail_thickness_ratio

The horizontal tail local thickness, calculated as:

local_chord(x) * htail_thickness_ratio

where x = lateral coord

Value is in ft

Float Yes
vtail_area

The fuselage-to-tip area of the static part of the vertical stabilizer (not counting the rudder area), in sqft. The vertical stabilizer and rudder will be simulated as a single wing with surfaces positioned in a way such that the overall incidence matches the current control surface deflection. This single surface will have the area of vtail_area and rudder_area combined. However, we recommend entering the exact area of each surface. This area will impact the yaw moment caused by the rudder deflection as well as the yaw moment caused by the vertical stabilizer.

Float Yes
vtail_span

The vertical tail span is the vertical distance from the vertical tail-fuselage intersection to the tip of the vertical tail, in ft.

A large vtail span will impact the roll moment of the propeller wash but also resist the aircraft roll movement. It will also counter adverse yaw and counter induced roll during rudder inputs.

Float Yes
vtail_sweep This is the angle the vertical tail leading edge makes with a vertical line perpendicular to the fuselage, as seen when looking at the side of the vertical tail (in degrees).       Yes
vtail_pos_lon

Longitudinal (z) position of the vtail and rudder surface - as measured at the centerline of the aircraft - from the Datum Reference Point in ft. This distance is measured positive in the forward (aircraft nose) direction.

The longitudinal position of the vtail impacts the yaw moment of the vtail and rudder surfaces. The vtail force vectors should be aligned with the real surface.

Float Yes
vtail_pos_vert

Vertical position of the vtail and rudder surface - as measured at the centerline of the aircraft - from the Datum Reference Point in ft. This distance is measured positive in the "up" direction.

Depending on the vertical position of the vtail, it can get into turbulences created by the wing located in front of it. The vertical position of the vtail will impact the roll moment created by the surface.

Float Yes
vtail_thickness_ratio

The vertical tail local thickness, calculated as:

local_chord(x) * vtail_thickness_ratio

where x = lateral coord

Value is in ft.

Float Yes
fuselage_length The fuselage length from nose to tail, in ft. Float Yes
fuselage_diameter The fuselage diameter, in ft. Float Yes
fuselage_center_pos The fuselage center from the Datum Reference Point, in ft.

1D Table of 3 Floats

Yes
elevator_area

Area of the moving part of the horizontal stabilizer (not counting the htail area), in sqft.

The horizontal stabilizer and elevator will be simulated as a single wing with surfaces positioned in a way that the overall incidence matches the current control surface deflection. This single surface will have the area of htail_area and elevator_area combined. However, we recommend entering the exact area of each surface. This area will impact the pitch moment caused by the elevator deflection aswell as the pitch moment caused by the horizontal stabilizer.

Float Yes
aileron_area The top surface aileron area, in sqft. Float Yes
rudder_area

Area of the moving part of the vertical stabilizer (not counting the vtail area),in sqft.

The vertical stabilizer and rudder will be simulated as a single wing with surfaces positioned in a way that the overall incidence matches the current control surface deflection. This single surface will have the area of vtail_area and rudder_area combined. However, we recommend entering the exact area of each surface. This area will impact the yaw moment caused by the rudder deflection aswell as the yaw moment caused by the vertical stabilizer.

Float Yes
elevator_up_limit

Upper angular limit of the elevator and htail combined control surface, in degrees.

This should be the maximum elevator deflection angle possible and will be scaled down by the elasticity table and the elevator_maxangle_scalar.

Float Yes
elevator_down_limit

Lower angular limit of the elevator and htail combined control surface, in degrees (absolute values only).

This should be the maximum elevator deflection angle possible and will be scaled down by the elasticity table and the elevator_maxangle_scalar.

Float Yes
aileron_up_limit

Upper angular limit of the aileron and wing combined control surface, in degrees.

This should be the maximum aileron deflection angle possible and will be scaled down by the elasticity table and the aileron_effectiveness.

Float Yes
aileron_down_limit

Lower angular limit of the aileron and wing combined control surface, in degrees (absolute values only).

This should be the maximum aileron deflection angle possible and will be scaled down by the elasticity table and the aileron_effectiveness. An excessive aileron down limit may increase the chance of the related wing surface stalling.

Float Yes
aileron_to_rudder_scale

The aileron to rudder ratio, used to link the two.

If set to a value other than 0, the rudder will be controlled by the aileron controller axis instead of the rudder controller axis. The scale defines the ratio between the aileron input applied to the rudder and the original aileron input.

Float Yes
aileron_span_outboard

The outboard aileron span, expressed as a Percent Over 100.

This is the ratio of wing length from the tip to the end of the aileron surface. A larger aileron will increase the roll moment of aileron deflection, but it will also increase the local drag generated by aileron deflection.

Float

Yes
rudder_limit

Angular limit in degrees (absolute values only) of the rudder and vtail combined control surface.

This should be the maximum rudder deflection angle possible and will be scaled down by the elasticity table and the rudder_maxangle_scalar.

Float Yes
rudder_trim_limit

Angular limit in degrees (absolute values only) of the rudder trim.

This deflection adds to the rudder deflection. This should be the maximum rudder trim deflection angle possible and will be scaled down by the elasticity table and the rudder_trim_effectiveness.

Float Yes
elevator_trim_limit Angular limit in degrees of the elevator trim. This deflection adds to the elevator deflection. This should be the maximum elevator trim deflection angle possible and will be scaled down by the elasticity table and the elevator_trim_effectiveness. Float Yes
elevator_trim_neutral

For many aircraft this will be the take off trim setting. The aircraft will start with this trim setting when starting on ground. This trim setting is not used for performance normalizations nor to achieve the target lift and drag values, and is used for indicators only. The htail_incidence will be used for performance normalization.

Float Yes
spoiler_limit

This sets the angular limit of the wing spoilers on an aircraft, in degrees (absolute values only), when on the ground. If this limit is 0, no spoilers exist for the aircraft.

Float Yes
air_spoiler_limit

Angular limit in degrees of the spoiler and wing combined control surface, in degrees (absolute values only) when in the air.

If set then this limit allows you to define a different limit when in air, than when on the ground. If this value is not set, then it will default to the spoiler_limit value.

Float Yes
spoilerons_available

Indicates whether the spoilers also behave as spoilerons for roll control (if spoilers are available): 0 = FALSE (no spoilerons) or 1 = TRUE.

Spoilerons will add spoiler deflection to aileron deflection based on aileron_to_spoileron_gain and min_ailerons_for_spoilerons.

Bool Yes
aileron_to_spoileron_gain Scales the spoileron deflection angle in relation to the aileron deflection angle set with min_ailerons_for_spoilerons (if spoilerons_available is TRUE).   Yes
min_ailerons_for_spoilerons

This value is used to indicate at what minimum aileron deflection  angle the spoilers become active for roll control, in degrees (absolute values only). Based on aileron_to_spoileron_gain.

Float Yes
min_flaps_for_spoilerons This value is used to indicate the minimum flap handle position where the spoilerons become active, in degrees (absolute values only). Float Yes
spoiler_extension_time Time, in seconds, necessary to fully extend the spoilers. Float Yes
spoiler_handle_available

This is used to configure the airplane with manual controls fort the spoiler deflections (TRUE, 1) or not (FALSE, 0).

Bool Yes
spoiler_disabled_by_flaps If TRUE (1), the spoilers will automatically retract when the flaps are extended. Default is FALSE (0). Bool Yes
auto_spoiler_auto_retracts If TRUE (1), the spoilers will automatically retract when the plane speed goes below auto_spoiler_min_speed. Default is TRUE (1). Bool Yes
auto_spoiler_available Sets whether auto spoilers are available (TRUE, 1) or not (FALSE, 0). Bool Yes
auto_spoiler_min_speed The minimum speed (in Knots) at which auto spoiler can activate. Defaults to 0. Float Yes
positive_g_limit_flaps_up

Flap positive load limit when up. Same dimension as gravity vector, in ft per second².

The aircraft will crash if the load factor reaches the G limit scaled by the load_safety_factor. An aircraft with a load factor hold fly by wire system, will respect these limits as load factor limits.

Float Yes
positive_g_limit_flaps_down

Flap positive load limit when down. Same dimension as gravity vector, in ft. per second².

The aircraft will crash if the load factor reaches the G limit scaled by the load_safety_factor. An aircraft with a load factor hold fly by wire system, will respect these limits as load factor limits.

Float Yes
negative_g_limit_flaps_up

Flap negative load limit when up. Same dimension as gravity vector, in ft. per second².

The aircraft will crash if the load factor reaches the G limit scaled by the load_safety_factor. An aircraft with a load factor hold fly by wire system, will respect these limits as load factor limits.

Float Yes
negative_g_limit_flaps_down

Flap negative load limit when down. Same dimension as gravity vector, in ft. per second².

The aircraft will crash if the load factor reaches the G limit scaled by the load_safety_factor. An aircraft with a load factor hold fly by wire system, will respect these limits as load factor limits.

Float Yes
load_safety_factor The load safety factor value. Float Yes
flap_to_aileron_scale The scale defines the ratio of aileron deflection based on flap deflection. Will deflect ailerons when flaps are extended. Float Yes
fly_by_wire

Sets whether fly-by-wire is available (TRUE, 1) or not (FALSE, 0).

A fly by wire control system disconnects the direct connection between yoke and rudder inputs and the control surfaces and adds a computer in between. This allows to activate control modes such as load factor hold.

Bool Yes
elevator_elasticity_table

A table that allows you to scale down the elevator control surface deflection angle depending on the current dynamic pressure. The table has a maximum of 5 values and has the following format:

dynamic_pressure:correction_factor,
dynamic_pressure:correction_factor,
etc...


Pressure is expressed as psf and the yoke correction factor is a Percent Over 100.

The dynamic pressure being airspeed dependent, this allows to reduce deflection based on speed. Dev Mode aircraft debugging tools allow you to get the current dynamic pressure. The dynamic pressure can also be obtained with the following formula:

dynamicpressure = 0,5 * airdensity * airspeed * airspeed

Default value is: 0.0:1.0

2D Table of Floats

No
aileron_elasticity_table

A table that allows you to scale down the aileron control surface deflection angle depending on the current dynamic pressure.

The table has a maximum of 5 values and has the following format:

dynamic_pressure:correction_factor,
dynamic_pressure:correction_factor,
etc...

Pressure is expressed as psf and the yoke correction factor is a Percent Over 100.

The dynamic pressure being airspeed dependent, this allows you to reduce deflection based on speed. Dev Mode aircraft debugging tools allow you to get the current dynamic pressure. The dynamic pressure can also be obtained with the following formula:

dynamicpressure = 0,5 * airdensity * airspeed * airspeed

Default value is: 0.0:1.0

2D Table of Floats

No
rudder_elasticity_table

A table that allows you to scale down the rudder control surface deflection angle depending on the current dynamic pressure. The table has a maximum of 5 values and has the following format:

dynamic_pressure:correction_factor,
dynamic_pressure:correction_factor,
etc...

Pressure is expressed as psf and the yoke correction factor is a Percent Over 100.

The dynamic pressure being airspeed dependent, this allows to reduce deflection based on speed. Dev Mode aircraft debugging tools allow you to get the current dynamic pressure. The dynamic pressure can also be obtained with the following formula:

dynamicpressure = 0,5 * airdensity * airspeed * airspeed

Default value is: 0.0:1.0

2D Table of Floats

No
elevator_trim_elasticity_table

A table that allows you to scale down the elevator control surface deflection angle depending on the current dynamic pressure. The table has a maximum of 5 values and has the following format:

dynamic_pressure:correction_factor,
dynamic_pressure:correction_factor,
etc...

Pressure is expressed as psf and the yoke correction factor is a Percent Over 100.

The dynamic pressure being airspeed dependent, this allows to reduce deflection based on speed. Dev Mode aircraft debugging tools allow you to get the current dynamic pressure. The dynamic pressure can also be obtained with the following formula:

dynamicpressure = 0,5 * airdensity * airspeed * airspeed

Default value is: 0.0:1.0

2D Table of Floats

No
controls_reactivity_scalar

The reactivity scalar for all controls.

Float Yes

### [AERODYNAMICS]

This section is for defining the aerodynamics of an aircraft. The available parameters are:

Parameter Description Type Required
lift_coef_pitch_rate

Defines how much lift will be added to the overall lift formula based on the current pitch rotation speed.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section.

Float Yes if using legacy flight model, No otherwise.
lift_coef_daoa

Defines how much lift will be added to the overall lift formula based on the current angle of attack variation rate.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section.

Float Yes if using legacy flight model, No otherwise.
lift_coef_delta_elevator

Defines how much lift will be added to the overall lift formula based on the current elevator deflection angle.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section.

Float Yes if using legacy flight model, No otherwise.
lift_coef_horizontal_incidence

Defines how much lift will be added to the overall lift formula based on the current yaw angle of the aircraft.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section.

Float Yes if using legacy flight model, No otherwise.
lift_coef_flaps Defines the lift coefficient that will be added to the target lift coefficient obtained with the lift_coef_aoa_table of the airplane when at maximum flap expansion. Float Yes
lift_coef_spoilers Defines the lift coefficient that will be added to the target lift coefficient obtained with the lift_coef_aoa_table of the airplane when at maximum spoiler expansion. Float Yes
drag_coef_zero_lift

Defines the target drag of the airplane in clean configuration (ie: no propeller, no turbulence, no engine wash, no gears, no flaps, no spoilers, no deflections...), when there is zero lift. This is usually also called the $C_{D0}$ or $C_{DZeroLift}$. Zero lift may occur at an angle of attack of zero - reason for which $C_{D0}$ is sometimes the drag at an AoA of 0 - but most of the time, zero lift occurs at an angle of attack that is negative and the $C_{D0}$ does not correspond to the drag at AoA 0.

In the legacy FSX flight model, this defines the actual $C_{D0}$. In the modern flight model, this defines the target $C_{D0}$ that will be distributed over all the surfaces of the aircraft when building the airplane used in the aerodynamic surface simulation. Once the aircraft is built, it will then be normalized to match exactly the target $C_{D0}$.

Float Yes
drag_coef_flaps Defines the target drag added when flaps are fully extended. In the legacy FSX flight model, this defines the actual flap drag. In the modern flight model, this defines the target flap drag that will be distributed over all the flap surfaces of the aircraft when building the airplane used in the aerodynamic surface simulation. Once the aircraft is built, it will then be normalized to match exactly the target flap drag. Float Yes
drag_coef_gear

Defines the drag of the gears that will be applied at the location of the gear contact points and create the appropriate angular moment.

If the aircraft features retractable gears, this coefficient will be zero once the gears are retracted. For non retractable gears this will always be present. All aircraft which feature gears, retractable or not, should define a drag coefficient for gears. This drag coefficient should not be baked into the drag_coef_zero_lift otherwise the gear angular moment calculations will be wrong.

Float Yes
drag_coef_spoilers

Defines the target drag added when spoilers are fully extended.

In the legacy FSX flight model, this defines the actual flap drag. In the modern flight model, this defines the target spoiler drag that will be distributed over all the spoiler surfaces of the aircraft when building the airplane used in the aerodynamic surface simulation. Once the aircraft is built, it will then be normalized to match exactly the target spoiler drag.

Float Yes
presspt_fwd_Alpha0_pMAC Defines an additional forward offset applied to the overall pressure center of the wing when the wing surface is at an AoA of 0. The offset is defined as a ratio of the local Mean Aerodynamic Chord and negative values indicate a backwards offset. Float No
presspt_fwd_AlphaStall_pMAC Defines an additional forward offset applied to the overall pressure center of the wing when the wing surface is at an the stall AoA. The offset is defined as a ratio of the local Mean Aerodynamic Chord and negative values indicate a backwards offset. Float No
presspt_fwd_AlphaHiStall_pMAC Defines an additional forward offset applied to the overall pressure center of the wing when the wing surface is at high above the stall AoA (during a stall). The offset is defined as a ratio of the local Mean Aerodynamic Chord, and negative values indicate a backwards offset. Float No
side_force_slip_angle

Defines how much side force will be generated when the yaw angle is non zero (during a side slip).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use fuselage_lateral_cx to modify the side drag coefficient of the fuselage and rudder_lift_coef to modify the forces generated by the rudder.

Float Yes
side_force_roll_rate

Defines how much side force will be generated when the aircraft has some roll speed (during a roll).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the side force resulting from a roll is a complex combination of the effect of all the aircraft surfaces that cannot be directly controlled. Making sure the aircraft surfaces are correctly aligned and feature correct areas and coefficients will result in a realistic side force when rolling.

Float Yes if using legacy flight model, No otherwise.
side_force_yaw_rate

Defines how much side force will be generated when the yaw angle is changing.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use fuselage_lateral_cx to modify the side drag coefficient of the fuselage and rudder_lift_coef to modify the forces generated by the rudder.

Float Yes if using legacy flight model, No otherwise.
side_force_delta_rudder

Defines how much side force will be generated when the rudder is deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use rudder_lift_coef to modify the forces generated by the rudder deflection.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_horizontal_incidence

Defines how much pitch moment will be generated when the aircraft is yawing.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the rudder trim and, rudder area and rudder vertical position to modify the pitch moment generated generated by the rudder at zero deflection.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_delta_elevator

Defines how much pitch moment will be generated when the elevator is deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the elevator_lift_coef, elevator longitudinal position and elevator area to adjust this effect.

NOTE: Even in the modern flight model, the autopilot system may still use this variable to calculate the elevator deflection necessary to find a required pitch moment. The PID will usually compensate for wrong values, but this variable cannot be set to zero or very far off and must be relatively close to reality. You can use the legacy flight model tool to calculate the correct value that will then usually work with the autopilot. A value between -1 and -5 will usually work.

Float Yes
pitch_moment_delta_trim

Defines how much pitch moment will be generated when the elevator trim is deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the elevator_lift_coef, elevator longitudinal position and elevator area and scale the trim effect to adjust this effect.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_pitch_damping

Defines how much the pitch velocity will be dampened when the plane is pitching.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the elevator_lift_coef, elevator longitudinal position, fuselage_lateral_cx and elevator area to adjust this effect. The wings and even the rudder may also contribute to this effect.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_aoa_0

Defines how much the pitch moment will be generated at AoA 0.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the htail_incidence as the primary variable to impact the 0 AoA pitch moment.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_daoa

Defines how much the alpha velocity will be dampened when the plane is changing incidence.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the elevator_lift_coef, elevator longitudinal position, fuselage_lateral_cx and elevator area to adjust this effect. The wings and even the rudder may also contribute to this effect.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_flaps

Defines how much pitch moment will be generated when the flaps will be deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, refer to the flaps documentation to see how to move the flap lift on the longitudinal axis in order to control the pitch moment at each flap level.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_gear

Defines how much the pitch moment will be generated because of the gears.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the drag_coef_gear and the position of the gear contact points to change the angular moments generated by gears.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_spoilers

Defines how much pitch moment will be generated when the spoilers will be deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, this will be automatically simulated and there is no way yet to change the pitch moment generated by spoilers. It will be an automatic effect of the spoiler deflection and mostly dependent on the drag generated by the spoilers and the vertical position of the wings.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_delta_elevator_propwash

Defines how much pitch moment will be generated when the elevator is deflected and there is a propeller spinning (prop wash).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model this is automatically simulated based on how air is accelerated by the propeller and blown onto the control surfaces. However one can use the elevator_lift_coef, elevator longitudinal position and elevator area to adjust this effect. In the modern flight model, this effect only works if the propeller is blowing air onto the control surfaces. If the propeller is under a wing, far from any surface, this effect will not occur.

Float Yes if using legacy flight model, No otherwise.
pitch_moment_pitch_propwash

Defines how much pitch moment will be generated when the plane is pitching and there is a propeller spinning (prop wash).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model this is automatically simulated based on how air is accelerated by the propeller and blown onto the control surfaces. However one can use the elevator_lift_coef, elevator longitudinal position and elevator area to adjust this effect. In the modern flight model, this effect only works if the propeller is blowing air onto the control surfaces. If the propeller is under a wing, far from any surface, this effect will not occur.

Float Yes if using legacy flight model, No otherwise.
roll_moment_slip_angle

Defines how much roll moment will be generated when the aircraft is yawing or side slipping.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, most of the roll will be induced by the difference in lift between one wing and the other, and the rudder will work against this effect. Adjust the shape of the wing via wing_sweepwing_dihedralwing_twistwing_camber, the position of the wing, and the vertical position of the rudder, the rudder area and rudder lift coefficient to adjust this effect. Some of these parameters will work against each other. Induced roll is a very complex effect to balance which will depend on many factors.

Float Yes if using legacy flight model, No otherwise.
roll_moment_roll_damping

Defines how much the roll speed will be dampened based on the current roll speed.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, most of the roll damping will be the result of the wings, the elevator and the rudder resisting roll. You can also use roll_stability and roll_gyro_stability to add more roll damping.

Float Yes if using legacy flight model, No otherwise.
roll_moment_yaw_rate

Defines how much roll moment will be generated when the aircraft is rotating around the yaw axis.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, most of the roll will be induced by the difference in lift between one wing and the other, and the rudder will work against this effect. Adjust the shape of the wing via wing_sweepwing_dihedralwing_twistwing_camber, the position of the wing, and the vertical position of the rudder, the rudder area and rudder lift coefficient to adjust this effect. Some of these parameters will work against each others. Induced roll is a very complex effect to balance which will depend on many factors.

Yes if using legacy flight model, No otherwise.
roll_moment_spoilers

Defines how much roll moment will be generated when the spoilers will be deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, this will be automatically simulated and there is no way yet to change the roll moment generated by spoilers.

Float Yes if using legacy flight model, No otherwise.
roll_moment_delta_aileron

Defines how much roll moment will be generated when the ailerons are deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the aileron_span_outboard, aileron_effectiveness and the aileron up and down angles to control this effect.

Float Yes if using legacy flight model, No otherwise.
roll_moment_delta_rudder

Defines how much roll moment will be generated when the rudder is deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, most of the roll will be induced by the difference in lift between one wing and the other, and the rudder will work against this effect. Adjust the shape of the wing via wing_sweepwing_dihedralwing_twistwing_camber, the position of the wing, and the vertical position of the rudder, the rudder area, and rudder lift coefficient, to adjust this effect. Some of these parameters will work against each others. Induced roll is a very complex effect to balance which will depend on many factors.

Float Yes if using legacy flight model, No otherwise.
roll_moment_delta_aileron_trim_scalar

Defines how much roll moment will be generated when the aileron trim is are deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the aileron_span_outboard, aileron_trim_effectiveness and aileron up and down angles to control this effect.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_slip_angle

Defines how much yaw moment will be generated when the aircraft is yawing or side slipping.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use fuselage_lateral_cx to modify the side drag coefficient of the fuselage and rudder_lift_coef to modify the forces generated by the rudder. The longitudinal position of the fuselage and rudder will have a big impact on the yaw moment. If most of the fuselage is behind the CG, the fuselage will have a stabilizing effect.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_roll

Defines how much yaw moment will be generated when the aircraft has some roll speed (during a roll).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the yaw moment resulting from a roll is a complex combination of the effect of all the aircraft surfaces that cannot be directly controlled. Adjusting the rudder surface parameters will have the largest effect here but the wing will have an effect too. Making sure the aircraft surfaces are correctly aligned and feature correct areas and coefficients will result in a realistic yaw moment when rolling.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_yaw_damping

Defines how much the yaw speed will be dampened based on the current yaw speed.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, most of the yaw damping will be the result of the rudder and fuselage, but the wings contribute as well. You can also use yaw_stability and yaw_gyro_stability to add more yaw damping.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_yaw_propwash

Defines how much yaw moment will be generated when the plane is yawing and there is a propeller spinning (prop wash).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model this is automatically simulated based on how air is accelerated by the propeller and blown onto the control surfaces. However one can use the rudder_lift_coef, rudder longitudinal position and rudder area to adjust this effect. In the modern flight model, this effect only works if the propeller is blowing air onto the control surfaces. If the propeller is under a wing, far from any surface, this effect will automatically not occur.

Yes if using legacy flight model, No otherwise.
yaw_moment_delta_aileron

Defines how much yaw moment will be generated when the ailerons are deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, this will mostly be caused by a difference in drag between both wings because of the difference in airspeed between both wings and the difference in deflection of both ailerons. Use the aileron_up_drag_coef, aileron_down_drag_coef and aileron up & down angles to control this effect.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_delta_rudder

Defines how much yaw moment will be generated when the rudder is deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use rudder_lift_coef to modify the moment generated by the rudder deflection. The longitudinal position of the rudder also plays an important role.

Float Yes if using legacy flight model, No otherwise.
yaw_moment_delta_rudder_propwash

Defines how much yaw moment will be generated when the plane rudder is deflected and there is a propeller spinning (prop wash).

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model this is automatically simulated based on how air is accelerated by the propeller and blown onto the control surfaces. However one can use the rudder_lift_coef, rudder longitudinal position and rudder area to adjust this effect. In the modern flight model, this effect only works if the propeller is blowing air onto the control surfaces. If the propeller is under a wing, far from any surface, this effect will automatically not occur.

Yes if using legacy flight model, No otherwise.
yaw_moment_delta_rudder_trim_scalar

Defines how much yaw moment will be generated when the rudder trim is are deflected.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, use the rudder_trim_effectiveness, rudder area and rudder max deflection to control this.

Float Yes if using legacy flight model, No otherwise.
compute_aero_center

Defines if the aerodynamic center longitudinal position should be placed computationally or manually. In legacy FSX, the aerodynamic center was in a constant position and computed based on the pitch moment data and moment of inertia values. This would still work with the modern flight model, but we recommend disabling the computation of the aerodynamic center (setting it to 0) and positioning this manually with aero_center_lift.

Float Yes
aero_center_lift

When compute_aero_center is set to 0 and the aerodynamic center is positioned manually, this variable allows you to define the longitudinal position of the aerodynamic center. For the modern flight model, this does not force the position of the aerodynamic center during the simulation because the aerodynamic center is not static in the modern flight model as it is the result of complex pressure forces applied on the surfaces which cause a moving aerodynamic center. It is however usually very close to 25% and will move between 20% and 30%. So, we use this variable to longitudinally align the wing surfaces with the wing geometry, considering that the aerodynamic center is located at 25% MAC. Again, this does not mean that the aero center will then stay at 25% MAC during the simulation, it will just be used to initialize the surface position once at start.

Float Yes
aileron_up_drag_coef

Defines the drag added by upwards aileron deflection. This parameter has a significant impact on adverse yaw. Reduce upward deflection drag to get more adverse yaw. This parameter is multiplied by the aileron deflection angle and internal coefficients.

Default is 0.5. This can be scaled with the aileron_up_drag_scalar parameter in the [FLIGHT_TUNING] section and is further modified by internal coefficients.

Float No
aileron_down_drag_coef

Defines the drag added by upwards aileron deflection. This parameter has a significant impact on adverse yaw. Increase downward deflection drag to get more adverse yaw. This parameter is multiplied by the aileron deflection angle.

Default is 1. This can be scaled with the aileron_down_drag_scalar parameter in the [FLIGHT_TUNING] section and is further modified by internal coefficients.

Float No
elevator_lift_coef

Defines the lift coefficient slope of the elevator control surface. This will have a direct impact on elevator authority and pitch stability. The elevator lift coefficient slope is usually dependent on the elevator aspect ratio and should be between 1.0 and 𝝅.

Default is 5.0, and generally values will always fall between 1.0 and 5.0, with a theoretical maximum of 2𝝅 and a recommended value between 2.0 (for less authority and stability) and 5.0 (for more authority and stability). This can be scaled with the elevator_effectiveness parameter in the [FLIGHT_TUNING] section.

Float No
rudder_lift_coef

Defines the lift coefficient slope of the rudder control surface. This will have a direct impact on rudder authority, yaw stability, adverse yaw and induced roll. The rudder lift coefficient slope is usually dependent on the rudder aspect ratio and should be between 1.0 and 𝝅.

Default is 5.0, and generally values will always fall between 1.0 and 5.0, with a theoretical maximum of 2𝝅 and a recommended value between 2.0 (for less authority and stability) and 5.0 (for more authority and stability). This can be scaled with the rudder_effectiveness parameter in the [FLIGHT_TUNING] section.

Float No
lift_coef_aoa_table

This table allows to define the clean aircraft lift coefficient vs AoA polar (in radians). The lift vs AoA table defines how much lift the aircraft generates at various AoAs. Table has a maximum if 13 entries with the format:

lift_coef:AoA_alpha,
lift_coef:AoA_alpha,
lift_coef:AoA_alpha,
etc...

In the modern flight model, this is used during the aircraft surfaces construction as a lift target that the aircraft should achieve at various angles of attack. This will impact the wing surfaces only, but the total lift will consider all surfaces. It describes the lift in clean configuration (ie: zero slip, no propeller, no gears, no control surface deflection). Once the aircraft is created, if will be normalized so that the effective lift coefficients measured actually match the target lift coefficients.

NOTE: The lift coefficients are only matched between AoAs 0 and the stall AoA. For other AoAs all around the 360° of the polar, it will be a natural consequence of the setup of the aerodynamic surfaces and other parameters. The polar does not need to be accurately defined in detail for AoAs outside of the -10° to stall +10° range in this table.

2D Table of Floats Yes
lift_coef_ground_effect_mach_table

This table allows you to scale the ground effect intensity. This defines the maximum ground effect on the lift component but will impact the maximum effect on the induced drag component proportionally as well. Even though this table allows you to define the ground effect at various mach levels, it is the primary way to set the ground effect intensity. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...
2D Table of Floats Yes
lift_coef_mach_table

Scales the lift coefficient based on the mach level. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the lift coefficient at higher mach levels is automatically impacted by a progressive detaching of the laminar airflow over the surfaces.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
lift_coef_delta_elevator_mach_table

Scales the delta elevator lift coefficient based on the mach level. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
lift_coef_daoa_mach_table

Scales the lift coefficient impacted by the change in AoA based on the mach level. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the lift coefficient at higher mach levels is automatically impacted by a progressive detaching of the laminar airflow over the surfaces.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
lift_coef_pitch_rate_mach_table

Scales the lift coefficient impacted by the change in pitch based on the mach level. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the lift coefficient at higher mach levels is automatically impacted by a progressive detaching of the laminar airflow over the surfaces.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
lift_coef_horizontal_incidence_mach_table

Scales the lift coefficient impacted by the change in yaw based on the mach level. The table has the format:

lift_coef:mach,
lift_coef:mach,
lift_coef:mach,
etc...

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model this effect is natively obtained through aerodynamic simulation of the surfaces defined in the [AIRPLANE_GEOMETRY] section. In the modern flight model, the lift coefficient at higher mach levels is automatically impacted by a progressive detaching of the laminar airflow over the surfaces.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
drag_coef_zero_lift_mach_tab

Adds drag based on the mach level. In the modern flight model, the drag coefficient at higher mach levels is automatically impacted by a progressive detaching of the laminar airflow over the surfaces. However this table allows to add more drag at specific mach levels to simulate a mach wall or specific effects of drag due to turbulence at specific drag levels. Drag walls are not natively simulated yet and will need to be defined with this table. The table has the format:

drag_coef:mach,
drag_coef:mach,
drag_coef:mach,
etc...

2D Table of Floats

Yes
side_force_slip_angle_mach_table Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
side_force_delta_rudder_mach_table Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
side_force_yaw_rate_mach_table Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
side_force_roll_rate_mach_table Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_aoa_table

Influence CoL computation if not prescribed

Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_delta_elevator_aoa_table

AoA(alpha) is given in DEGREES

Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_horizontal_incidence_aoa_table

AoA(alpha) is given in DEGREES

Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_daoa_aoa_table

AoA(alpha) is given in DEGREES

Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_pitch_alpha_table

AoA(alpha) is given in DEGREES

Legacy FSX table, not used in the modern flight model.

2D Table of Floats

Yes if using legacy flight model, No otherwise.
pitch_moment_delta_elevator_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
pitch_moment_daoa_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
pitch_moment_pitch_rate_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
pitch_moment_horizontal_incidence_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
pitch_moment_aoa_0_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_aoa_table

${C_L}$ (roll moment coefficient) versus AoA-

Legacy FSX table, not used in the modern flight model.

2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_slip_angle_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_roll_rate_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_delta_aileron_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_slip_angle_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_delta_rudder_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_delta_aileron_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_yaw_rate_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
roll_moment_roll_rate_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_aoa_table

${C_n}$ (yaw moment coef) versus AoA.

Legacy FSX table, not used in the modern flight model.

2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_slip_angle_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_yaw_rate_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_delta_rudder_aoa_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_slip_angle_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_delta_rudder_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_delta_aileron_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_yaw_rate_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
yaw_moment_roll_rate_mach_table Legacy FSX table, not used in the modern flight model. 2D Table of Floats Yes if using legacy flight model, No otherwise.
elevator_scaling_table

Allows you to define a non linear elevator deflection curve on top of the input curve settings possible in the simulator. The table defines how the input value is scaled for each range of input values. The table has the following format (maximum 16 value pairs):

input_value:scale,
input_value:scale,
input_value:scale,
etc...

Default is to scale all input values by 1.

2D Table of Floats Yes
aileron_scaling_table

Allows to define a non linear aileron deflection curve on top of the input curve settings possible in the simulator. The table defines how the input value is scaled for each range of input values. The table has the following format (maximum 16 value pairs):

input_value:scale,
input_value:scale,
input_value:scale,
etc...

Default is to scale all input values by 1.

2D Table of Floats Yes
rudder_scaling_table

Allows to define a non linear rudder deflection curve on top of the input curve settings possible in the simulator. The table defines how the input value is scaled for each range of input values. The table has the following format (maximum 16 value pairs):

input_value:scale,
input_value:scale,
input_value:scale,
etc...

Default is to scale all input values by 1.

2D Table of Floats Yes
aileron_load_factor_effectiveness_table

Scaling of roll_moment_delta_aileron versus gravity forces.

Legacy FSX table, not used in the modern flight model.

2D Table of Floats Yes if using legacy flight model, No otherwise.
lift_coef_at_drag_zero

When building the surfaces of the aircraft, the modern flight model allows us to use the following drag formula:

${C_D} = {C_{D0}} + K(C_L - C_{L0})^{2}$

This parameter represents the ${C_{L0}}$ parameter of this formula in the clean configuration. The aircraft is built trying to match this drag polar and then a normalization pass is done on all surfaces to perfectly match the target polar. This parameter has also been added to the legacy FSX flight model that now also allows ${C_{D0}}$ to not be always zero.

Float Yes
lift_coef_at_drag_zero_flaps

When building the surfaces of the aircraft, the modern flight model allows us to use the following drag formula:

${C_D} = {C_{D0}} + K(C_L - C_{L0})^{2}$

This parameter represents the ${C_{L0}}$ parameter of this formula in the landing configuration with flaps fully deployed. The aircraft is built trying to match this drag polar and then a normalization pass is done on all surfaces to perfectly match the target polar. This parameter has also been added to the legacy FSX flight model that now also allows ${C_{D0}}$ to not be always zero.

Float Yes
fuselage_lateral_cx

Defines the perpendicular drag coefficient of the fuselage, which occurs when the airflow is going perpendicular to the front axis (ie: sideways - left to right or right to left) but also going up and down. This coefficient has an impact on drag when side slipping, as well as a general impact on yaw stability and pitch stability.

Default is 0.4 - which is about the perpendicular drag of a cylinder - and the value should usually fall between 0.2 and 0.8 for most aircraft.

Float No

### [FLIGHT_TUNING]

This section is for tuning various aspects of the flight model for an aircraft. The available parameters are:

Parameter Description Type Required
modern_fm_only

This can be set to 1 (true) to force the aircraft to use the modern flight model, regardless of what the user may have selected in the Microsoft Flight Simulator options.

Default value is 0 (false).

Boolean No
empty_CG_deviation_limit

This value allows you to define - in ft - a limit to the maximum deviation that will be allowed in the weight & balance UI menu (where users can change the empty CG position).

Default value is infinite, and it can also can accept 0.

Float No
icing_scalar

With this value you can scale up or down the effects of icing on the plane. This will affects the effect of icing on lift and on the weight.

The default value is 1.0 (100% of the effect). Can accept 0.0 to remove all effects of icing.

Float No
cruise_lift_scalar

Scales the target lift coefficient as looked up from lift_coef_aoa_table over the entire range of AoAs.

Default value is 1.

Float No
parasite_drag_scalar

Scales the target drag coefficient as defined in drag_coef_zero_lift.

Default value is 1.

Float No
induced_drag_scalar

Scales the induced drag target as defined by the target induced drag formula:

${C}_{Di} = \frac {{C_l} ^{2}} {pi \times AR \times e}$

This scalar applies to the FLAP 0 configuration (in clean configuration, ie: no propeller, no turbulence, no engine wash, no gears, no flaps, no spoilers, no deflections...).

Default value is 1.

Float No
flap_induced_drag_scalar

Scales the induced drag target as defined by the target induced drag formula:

${Cd}_{i} = \frac {Cl ^{2}} {pi \times AR \times e}$

This scalar applies to the FULL FLAP configuration (ldg).

Default value is 1.

Float No
elevator_effectiveness

This scalar scales the elevator_lift_coef parameter in the [AERODYNAMICS] section.

Default value is 1.

Float No
elevator_maxangle_scalar

Scales the deflection angle of the elevator control surface up to the max deflection indicated in elevator_xxx_limit and already scaled by the elevator_elasticity_table.

The default value is 1.0, yet if the limit angles are matching the real aircraft, this scalar should be smaller than one as the effective deflection will be aligned with the overall htail and elevator chord. A value between 0.5 and 0.75 will work with most airplanes.

Float No
aileron_effectiveness

Scales the elevator lift coefficient slope as defined in elevator_lift_coef in the [AERODYNAMICS] section. Increases or decreases elevator authority or "twitchyness" without affecting the deflection angle.

Default value is 1.

Float No
rudder_effectiveness

This scalar scales the rudder_lift_coef parameter in the [AERODYNAMICS] section. Values will increase or decrease lift authority or "twitchyness" without affecting the deflection angle.

Default value is 1.

Float No
rudder_maxangle_scalar

Scales the deflection angle of the rudder control surface up to the max deflection indicated in rudder_limit and already scaled by the elevator_elasticity_table.

The default value is 1, and if the limit angles are matching the real aircraft, this scalar should be less than 1 as the effective deflection will be aligned with the overall vtail and rudder chord. A value between 0.5 and 0.75 will work with most airplanes.

Float No
pitch_stability

Sets a target value for aerodynamic resistance to pitch rotation for the plane. In the legacy flight model, this will scale the pitch_moment_pitch_damping variable. In the modern flight model, this will set a target aerodynamic resistance value that the flight model will try to reach by adding more rotation resistance to each surface. As this system can only add more resistance, there will be a minimum native aerodynamic resistance below which the system can't go. By setting a low target, such as 0.1, the target is usually below the native aerodynamic rotation resistance which means that this parameter will have no effect. To add more aerodynamic resistance, use larger values.

NOTE: Aerodynamic resistance to rotation is relative to the local air mass. If the local airmass is turbulent, increasing rotation resistance will make turbulence impact more on the aircraft.Default value is 1.

Float No
roll_stability

Sets a target value for aerodynamic resistance to roll rotation for the plane. In the legacy flight model, this will scale the roll_moment_roll_damping variable. In the modern flight model, this will set a target aerodynamic resistance value that the modern flight model will try to reach by adding more rotation resistance to each surface. As this system can only add more resistance, there will be a minimum native aerodynamic resistance below which the system can't go. By setting a low target, such as 0.1, the target is usually below the native aerodynamic rotation resistance which means that this parameter will have no effect. To add more aerodynamic resistance, use larger values.

NOTE: Aerodynamic resistance to rotation is relative to the local air mass. If the local airmass is turbulent, increasing rotation resistance will make turbulence impact more on the aircraft.Default value is 1.

Float No
yaw_stability

Sets a target value for aerodynamic resistance to yaw rotation for the plane. In the legacy flight model, this will scale the yaw_moment_yaw_damping variable. In the modern flight model, this will set a target aerodynamic resistance value that the modern flight model will try to reach by adding more rotation resistance to each surface. As this system can only add more resistance, there will be a minimum native aerodynamic resistance below which the system can't go. By setting a low target, such as 0.1, the target is usually below the native aerodynamic rotation resistance which means that this parameter will have no effect. To add more aerodynamic resistance, use larger values.

NOTE: Aerodynamic resistance to rotation is relative to the local air mass. If the local airmass is turbulent, increasing rotation resistance will make turbulence more impacting on the aircraft.Default value is 1.

Float No
pitch_gyro_stability

This variable controls pitch gyroscopic stability. Unlike aerodynamic stability - which is relative to the local airmass - gyroscopic stability is world relative and will not make the aircraft more sensitive to turbulence. It will have the opposite effect in reality: making the aircraft more stable relative to the world, it will become less sensitive to turbulent air. Gyroscopic stability in an aircraft is caused by turning parts such as the propellers or engine axis or turbines.

Default value is 0.

Float No
roll_gyro_stability

This variable controls roll gyroscopic stability. Unlike aerodynamic stability - which is relative to the local airmass - gyroscopic stability is world relative and will not make the aircraft more sensitive to turbulence. It will have the opposite effect in reality: making the aircraft more stable relative to the world, it will become less sensitive to turbulent air. Gyroscopic stability in an aircraft is caused by turning parts such as the propellers or engine axis or turbines.

Default value is 0.

Float No
yaw_gyro_stability

This variable controls yaw gyroscopic stability. Unlike aerodynamic stability - which is relative to the local airmass - gyroscopic stability is world relative and will not make the aircraft more sensitive to turbulence. It will have the opposite effect in reality: making the aircraft more stable relative to the world, it will become less sensitive to turbulent air. Gyroscopic stability in an aircraft is caused by turning parts such as the propellers or engine axis or turbines.

Default value is 0.

Float No
elevator_trim_effectiveness

Scales the elevator trim deflection angle and maximum trim deflection angle as defined in elevator_trim_limit.

Default value is 1.

Float No
aileron_trim_effectiveness

Scales the aileron trim deflection angle and maximum trim deflection angle.

Default value is 1.

Float No
rudder_trim_effectiveness

Scales the rudder trim deflection angle and maximum trim deflection angle as defined in rudder_trim_limit.

Default value is 1.

Float No
aileron_up_drag_scalar

Scales the drag added by upwards aileron deflection as defined in aileron_up_drag_coef parameter in the [AERODYNAMICS] section. This parameter has a significant impact on adverse yaw. Reduce upward deflection drag to get more adverse yaw.

Default value is 1.

Float No
aileron_down_drag_scalar

Scales the drag added by downwards aileron deflection as defined in aileron_down_drag_coef parameter in the [AERODYNAMICS] section. This parameter has a significant impact on adverse yaw. Increase downward deflection drag to get more adverse yaw.

Default value is 1.

Float No
hi_alpha_on_roll

Multiplier on the effects on roll at high angles of attack. This parameter is used in the legacy FSX flight model only to define the stall characteristics of the aircraft. It is not used anymore in the modern flight model.

The default value is 1.

Float No
hi_alpha_on_yaw

Multiplier on the effects on yaw at high angles of attack. This parameter is used in the legacy FSX flight model only to define the stall characteristics of the aircraft. It is not used anymore in the modern flight model.

The default value is 1.

Float No
p_factor_on_yaw

Scales the amount of p-factor induced yaw. P-factor is the result of the propeller providing asymmetric thrust when the propeller is not aligned with the trajectory.

The default value is 1.

Float No
torque_on_roll

Scales the amount of torque that is transmitted from the engine onto the aircraft. When the engine starts to roll into one direction, it will cause the aircraft to roll into the other direction.

The default value is 1.

Float No
gyro_precession_on_pitch

Scales the amount of gyroscopic precession the engine causes on the aircraft's pitch.

The default value is 1.

Float No
gyro_precession_on_yaw

Scales the amount of gyroscopic precession the engine causes on the aircraft's yaw.

The default value is 1.

Float No
engine_wash_on_roll

Scales the amount of impact the engine wash will have on the surfaces of the aircraft causing the aircraft to roll.

The default value is 0.

Float No
rudder_engine_wash_on_roll

Scales the amount of added rudder trim compensating engine wash impact on roll. This parameter is separated from the actual rudder trim because it will be disabled with the engine wash on roll depending on piloting assistance's.

The default value is 1.

Float No
wingflex_scalar

Wingflex is based on realistic lift force and gravity computations and default elasticity parameters for a standard wing. This scalar allows to scale the amount of wingflex written to the WING_FLEX_PCT SimVar.

Default value is 1.

Float No
wingflex_offset Wingflex is based on realistic lift force and gravity computations and default elasticity parameters for a standard wing. This offset allows to offset the amount of wingflex

written to the WING_FLEX_PCT SimVar.

Default value is 0.

Float No

### [REFERENCE SPEEDS]

This section contains various reference speed values used to tune the flight model. The available parameters are:

Parameter Description Type Required
full_flaps_stall_speed

Speed at which the aircraft will stall when flaps are at full, in ktas.

Default value is 0.

Float No
flaps_up_stall_speed

Speed at which the aircraft will stall when flaps are up, in ktas.

Default value is 0.

Float No
cruise_speed

The aircraft cruise speed, in ktas.

Default value is 0.

Float No
cruise_mach

The aircraft cruise speed, in Mach.

Default value is 0.

Float No
crossover_speed

The aircraft crossover speed, in kias.

Default value is 0.

Float No
max_mach

The maximum speed for the aircraft, in Mach.

NOTE: Only valid for Jet and Turboprop engines.

Default value is 0.9.

Float No
max_indicated_speed

The maximum speed indicated in the aircraft UI, in kias.

Default value is 0.

Float No
max_flaps_extended

The maximum aircraft speed with flaps extended, in kias.

Default value is 0.

Float No
normal_operating_speed

The normal operating speed of the aircraft, in kias.

Default value is 0.

Float No
airspeed_indicator_max

The maximum airspeed indicator value in the UI, in kias.

Default value is 0.

Float No
rotation_speed_min

The minimum rotation speed required, in Knots.

Default value is -1.

Float No
climb_speed

The aircraft climb speed, in Knots.

Default value is 0.

Float No
cruise_alt

The aircraft cruise altitude, in ft.

Default value is 1500.

Float No
takeoff_speed

The aircraft takeoff speed, in Knots.

Default value is 55.

Float No
spawn_altitude

The spawn altitude, in ft.

Default value is 1500.

Float No
spawn_cruise_altitude

The spawn cruise altitude, in ft.

Default value is 1500.

Float No
spawn_descent_altitude

The spawn descent altitude, in ft.

Default value is 500.

Float No
best_angle_climb_speed

The best angle climb speed, in Knots.

Default value is 0.

Float No
approach_speed

The required approach speed, in Knots.

Default value is 0.

Float No
best_glide

The best glide speed, in Knots.

Default value is 0.

Float No
max_gear_extended

The maximum speed with landing gear extended, in Knots.

Default value is 0.

Float No
best_single_engine_rate_of_climb_speed

This is the best single-engine rate of climb speed (the Blue line speed, $V_{yse}$ ), in Knots.

Default value is 0.

Float No
minimum_control_speed

This is the speed below which aircraft control cannot be maintained if the critical engine fails under a specific set of circumstances (generally known as the $V_{mc}$ ). Value is in Knots.

Default value is 0.

Float No

### [ALPHA PROTECTION]

Alpha protection is a system which prevents the AoA from getting too high. This is done by software monitoring the plane's angle of attack sensor, and when a high alpha situation is detected, the software lowers the nose of the plane to maintain a high - but still safe - AoA. This system is designed to prevent pilots from stalling the aircraft and to allow them to get the best possible performance in emergency e.g. in a wind-shear. The following parameters can be used to control this system:

Parameter Description Type Required
off_limit The alpha (in degrees) below which the alpha protection can be disabled (if it is also also below the off_yoke_limit). Float No
off_yoke_limit The yoke position (as a percentage) below which the alpha protection can be disabled (if also below the off_limit). Float No
on_limit The alpha (in degrees) above which the alpha protection timer starts. Float No
on_goal The alpha (in degrees) that the alpha protection will attempt to reach when triggered. Float No
timer_trigger The duration (in seconds) the alpha must be above on_limit before the alpha protection is triggered. Float No

### [STALL PROTECTION]

This section deals with the aircraft stall protection systems. The available parameters are:

Parameter Description Type Required
stall_protection Whether Stall Protection is enabled (TRUE, 1) or not (FALSE, 0). Bool No
off_limit Alpha below which the Stall Protection can be disabled, in degrees (if also below off_yoke_limit). Float
off_yoke_limit Yoke position percentage below which the Stall Protection can be disabled (if also below off_limit). Float
on_limit Alpha - in degrees - above which the Stall Protection timer starts. Float
on_goal The alpha - in degrees - that the Stall Protection will attempt to reach when triggered. Float
timer_trigger Duration, in seconds, that the alpha must be above on_limit before the Alpha Protection is triggered. Float

### [FLAPS.N]

This section is for tuning the different flaps for the aircraft. You can have multiple [FLAPS.N] sections where N relates to the flap being defined from 0 up to the number of flaps - 1. For example, if you have two flaps you would have two sections, [FLAPS.0] and [FLAPS.1].

The available parameters are:

Parameter Description Type Required
type

Defines the flaps type.

Integer:

1. 0 = none
2. 1 = trailing edge
3. 2 = leading edge
Yes
system_type Defines the type of electrical system that drives the flaps to deflect.

Integer:

1. 0 = electrical
2. 1 = hydraulic
3. 2 = pneumatic
4. 3 = manual
5. 4 = none
Yes
system_type_index If using electrical flaps, this parameter specifies the index of the flaps motor circuit. Default is 0. Integer No
span-outboard Outboard span area, as a Percent Over 100 This ishow far out from the middle the flaps stretch. On most planes this will be 1.0 - aileron_span_outboard. This value needs to be matching the lift and drag added by flaps. Small flap systems should add small amounts of lift. Float No
extending-time Time it takes for the flap set to extend to the fullest deflection angle specified (in seconds). Float No
flaps-sequence-increasing If set, this specifies that these flaps should only start moving towards the down position when the flaps with the corresponding index have finished moving. Defaults is -1, which means no such restriction should be applied. Integer No
flaps-sequence-decreasing If set, this specifies that these flaps should only start moving towards the up position when the flaps with the corresponding index have finished moving. Defaults is -1, which means no such restriction should be applied. Integer No
damaging-speed Speed above which the flaps begins to get damaged, if extended, in Knots. Float No
blowout-speed Speed above which the flaps are blown out, in Knots. Float No
maneuvering_flaps Sets whether maneuvering flaps are available (TRUE, 1) or not (FALSE, 0). Bool No
delay_between_flap_index
lift_scalar

Scalar that allows you to scale the lift contribution of a specific flap system. This is necessary to compensate for the scale by the deflection angle in radians, in order to reach 100%. The flap lift formula is the following:

total_flap_lift = lift_coef_flaps * (system1.lift_scalar * system1.deflectionangleradians + system2.lift_scalar * system 2.deflectionangleradians...)

Default value is 1.

Float Yes
drag_scalar

Scalar that allows you to scale the drag contribution of a specific flap system. It is necessary to compensate for the scale by the deflection angle in radians, in order to reach 100%. The flap drag formula is the following:

total_flap_drag = drag_coef_flaps * (system1.drag_scalar * system1.deflectionangleradians + system2.drag_scalar * system 2.deflectionangleradians...)

Default value is 1.

Float Yes
pitch_scalar

The percentage of total pitch due to flap deflection that this flap set is responsible for at full deflection.

This is a legacy FSX parameter not used in the modern flight model. In the modern flight model, the pitch generated by flaps will depend on the lift added and the longitudinal position of the wings. The parameters of each flap level allow to move the wing longitudinally for each flap level to adjust the amount of pitch.

Default value is 1.

Float Yes
max_on_ground_position The maximal flap extension stage available when an aircraft is on the ground. This must be a value between 0 and the maximal stage described (see flaps-position.N). Integer No
altitude-limit Specifies an altitude (in ft) above which the flaps cannot be extended. Default is -1, which disables the feature. Float yes
flaps-position.i

This is a flap stage description, and you can have multiple definitions (starting at flaps-position.0) for each [FLAPS.N] section. The table of values takes the following 7 values in the given order:

• flap position - sets the flaps angular position for the stage, in degrees.
• airspeed limit - sets the airspeed limit for the stage, in Knots.
• drag scalar - sets a scalar to add or remove drag for the stage.
• lift scalar - sets a scalar to add or remove lift for the stage.
• area scalar - sets a scalar to add or remove area to the flap for the stage.
• add camber - sets an increase in the flap camber, raising the maximum lift coefficient or the upper limit to the lift a wing can generate.
• add aft feet - sets the center of lift for the flaps stage, where a positive value will move the center of lift forward (generating more pitch up) and a negative value will move it back (generating more pitch down).
• add incidence - sets an increase in the angle of incidence - which is the difference between the longitudinal axis of the aircraft and the chord line of the wing - in degrees.

1D Table of Floats

Yes
flaps-position-inhibit.i

This is a comma separated table of conditions which - if all valid - will inhibit the flaps settings from affecting the flaps at position i. There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1. Can be any of the following:

• "air" - plane is in the air
• "ground" - plane is on the ground
• "increasing" - inhibit only if rising flaps level
• "decreasing" - inhibit only if decreasing flaps level

1D Table of Strings

Yes
flaps-position-autoretract.i

This parameter sets the autoratract rules for flaps. There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1. The parameter requires a comma separated table of values in the following order:

• the flaps angle in degrees
• the airspeed in Knots at which the auto-retract triggers
• the new airspeed limit, in Knots

1D Table of Floats

Yes
flaps-position-maneuvering.i

When set to 1 (TRUE) flaps position i will have a dynamic maneuvering flaps behavior rather than a static degree value. Set to 0 (FALSE) to disable this feature for the flaps. There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1.

Boolean No
flaps-position-speed-factor.i

This parameter requires a table of values that set the correspondence between the speed (in Knots) of the plane and a factor (from 0 - 1) on the max angle of the flaps position i. For example:

flaps-position-speed-factor.0 = 0:1, 150:1, 240:0 ;

Here, between 0 and 150 you get the full flaps position, but above 150 it starts getting reduced linearly until 240 at which point it's 0.

There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1.

2D Table of Floats

No
flaps-position-speed-override-above.i

This parameter sets the override rules for flaps at the given position when above a certain speed. There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1. The parameter requires the following two values, separated by a comma:

• the flaps position to use as the override
• the speed (in Knots) above which the given flaps position is used instead of the current one.

1D Table of Floats

No
flaps-position-speed-override-below.i

This parameter sets the override rules for flaps at the given position when below a certain speed. There can be multiple entries for this parameter, one for each flaps position, with i starting at 0 and up to number of flaps - 1. The parameter requires the following two values, separated by a comma:

• the flaps position to use as the override
• the speed (in Knots) below which the given flaps position is used instead of the current one.

1D Table of Floats

No

### [INTERACTIVE POINTS]

Interactive Points are used to define the position of various doors of the aircraft as well as some other points to interact with Airport Services, such as the end of a fuel hose to interact with a FuelTruck.

The available parameters are:

Parameter Description Type Required
number_of_interactive_points

The number of interactive points being defined. Ïf greater than 0, each one needs to have a corresponding interactive_point.N parameter, counting from 0 up to number_of_interactive_points - 1.

Integer Yes
interactive_point.N

A table of values defining the interactive point. This table has the following format:

interactive_point.0 = Open Close Rate, Pos Z, Pos X, Pos Y, Type, Pitch, Bank, Heading, Jetway Left Bend, Jetway Left Deployment, Jetway Right Bend, Jetway Right Deployment, Jetway Top Horizontal, Jetway Top Vertical

1D Table of Floats

• [INTERACTIVE POINTS]