AIRCRAFT FLIGHT MODEL VARIABLES

The tables below indicate the properties for the Simulation Variables that can be used to get and set properties related to the physical properties and flight model of an aircraft. For information on the units listed for each variable, please see here: Simulation Variable Units

NOTE: When Microsoft Flight Simulator 2024 is running in multiplayer mode, only a small number of variables are communicated between aircraft. Those variables that are available will say so in the description as being either for "All Aircraft" or for "Shared Cockpit".

You can find a complete index of all available SimVars here: SimVar Index

 

 

General

Simulation Variable Description Units Settable
BETA DOT Beta dot Radians per second
DECISION ALTITUDE MSL Design decision altitude above mean sea level Feet (ft)
DECISION HEIGHT Design decision height Feet (ft)
DESIGN CRUISE ALT This design constant represents the optimal altitude the aircraft should maintain when in cruise. It is derived from the cruise_alt setting in the section of the flightmodel.cfg. Default is 1500ft. Feet (ft)
DESIGN SPAWN ALTITUDE CRUISE This design constant represents the spawn altitude for the aircraft when spawning in cruise. It is derived from the spawn_cruise_altitude setting in the section of the flightmodel.cfg. Default is 1500ft. Feet (ft)
DESIGN SPAWN ALTITUDE DESCENT This design constant represents the spawn altitude for the aircraft when spawning in descent. It is derived from the spawn_descent_altitude setting in the section of the flightmodel.cfg. Default is 500ft. Feet (ft)
DESIGN SPEED CLIMB This design constant represents the optimal climb speed for the aircraft. It is derived from the climb_speed setting in the section of the flightmodel.cfg. Default value is -1. Feet (ft) per second
DESIGN SPEED MIN ROTATION This design constant represents the minimum speed required for aircraft rotation. It is derived from the rotation_speed_min setting in the section of the flightmodel.cfg. Default value is -1. Feet (ft) per second
DESIGN SPEED VC This design constant represents the aircraft ideal cruising speed. It is derived from the cruise_speed setting in the section of the flightmodel.cfg. The default value is computed an internal function that uses the estimated cruise altitude and estimated cruise percent power, according of the engine type, the number of engines, the density, the wing area and some drag parameters. Normally this value is set in the CFG file and the default value is never used. Feet (ft) per second
DESIGN SPEED VS0 This design constant represents the the stall speed when flaps are fully extended. It is derived from the full_flaps_stall_speed setting in the section of the flightmodel.cfg. Default value is 0.8 x VS. kias
DESIGN SPEED VS1 This design constant represents the stall speed when flaps are fully retracted. It is derived from the flaps_up_stall_speed setting in the section of the flightmodel.cfg. Default value is 0. kias
DESIGN TAKEOFF SPEED This design constant represents the aircraft ideal takoff speed. It is derived from the takeoff_speed setting in the section of the flightmodel.cfg. Knots
DYNAMIC PRESSURE Dynamic pressure Pounds per square foot (psf)
ESTIMATED CRUISE SPEED Estimated cruise speed Feet (ft) per second
G FORCE Current g force GForce
G LIMITER SETTING This returns the setting of the G-limiter, as set using the GLimiterSetting parameter.

Enum:

  1. 0 = Off
  2. 1 = On
  3. 2 = Override
INCIDENCE ALPHA Angle of attack Radians
INCIDENCE BETA Sideslip angle Radians
IS TAIL DRAGGER True if the aircraft is a taildragger Bool
LINEAR CL ALPHA Linear CL alpha Per radian
MACH MAX OPERATE Maximum design mach Mach
MAX G FORCE Maximum G force attained Gforce
MIN DRAG VELOCITY Minimum drag velocity, in clean, with no input and no gears, when at 10000ft. Feet (ft) per second
MIN G FORCE Minimum G force attained Gforce
REFERENCE SPEED MAX IAS The maximum IAS that the aircraft can fly at. Knots
REFERENCE SPEED MAX IAS GEAR DOWN The maximum IAS that the aircraft can fly at with the landing gear extended. Knots
SEMIBODY LOADFACTOR X Deprecated, do not use! Number
SEMIBODY LOADFACTOR Y Acceleration along the axis Y divided by the gravity constant g (usually around 9.81m.s²) Number
SEMIBODY LOADFACTOR YDOT Derivative of SEMIBODY LOADFACTOR Y in relation to time. Per second
SEMIBODY LOADFACTOR Z Deprecated, do not use! Number
SIGMA SQRT Sigma sqrt Number
SIMULATED RADIUS Simulated radius Feet (ft)
STALL ALPHA The angle of attack which produces the maximum lift coefficient before entering into stall conditions. Radians
STATIC PITCH The angle at which static pitch stability is achieved. Radians
TYPICAL DESCENT RATE the typical (normal) descent rate for the aircraft. Feet (ft) per minute
WING AREA Total wing area Square feet (ft)
WING FLEX PCT The current wing flex. Different values can be set for each wing (for example, during banking). Set an index of 1 for the left wing, and 2 for the right wing. Percent Over 100
WING SPAN Total wing span Feet (ft)
YAW STRING ANGLE The yaw string angle. Yaw strings are attached to gliders as visible indicators of the yaw angle. Will only work when the yaw_string_available parameter is set to 1 (True). Radians
YAW STRING PCT EXTENDED Yaw string angle as a percentage. Will only work when the yaw_string_available parameter is set to 1 (True). Percent Over 100
ZERO LIFT ALPHA The angle of attack at which the wing has zero lift. Radians

 

 

Center Of Gravity

Simulation Variable Description Units Settable
CG AFT LIMIT

Most backward authorized position of the CG according to the POH.

NOTE: This is only valid for airplanes.

 Percent Over 100
CG FEET

The longitudinal CG position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FEET AFT LIMIT

The aft CG limit position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FEET LATERAL

The lateral CG position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FEET LATERAL LEFT LIMIT

The left hand lateral CG position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FEET LATERAL RIGHT LIMIT

The right hand lateral CG position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FEET FWD LIMIT

The forward CG limit position relative to the Datum Reference Point.

NOTE: This is only valid for helicopters.

 Feet (ft)
CG FWD LIMIT

Most forward authorized position of the CG according to the POH.

NOTE: This is only valid for airplanes.

 Percent Over 100
CG MAX MACH Deprecated, do not use! Mach
CG MIN MACH Deprecated, do not use! Mach
CG PERCENT

Longitudinal CG position as a percent of reference Chord.

NOTE: This is only valid for airplanes.

 Percent Over 100
CG PERCENT LATERAL

Lateral CG position as a percent of reference Chord.

NOTE: This is only valid for airplanes.

 Percent Over 100
STATIC CG TO GROUND

Static CG position with reference to the ground.

NOTE: This is only valid for airplanes.

 Feet (ft)

 

 

Interactive Points

These SimVars are used in relation to the values of the Interactive Points that have been defined for the aircraft. Each of these SimVars requires a name (or an index value) to be supplied, and this is the name (or index) of the corresponding interactive_point.N defined in the appropriate CFG file. This name can be given using the following format:

[SimVar]:'[COMPONENT_NAME]'_n

For example:

(A:INTERACTIVE POINT BANK:'Door_1'_n, Volts)

 

 

Simulation Variable Parameters Description Units Settable
INTERACTIVE POINT BANK

[0] Point Name (or index)

 Interactive Point orientation: Bank. Degrees
INTERACTIVE POINT HEADING [0] Point Name (or index) Interactive Point orientation: Heading. Degrees
INTERACTIVE POINT JETWAY LEFT BEND [0] Point Name (or index) Interactive Point Jetway constant, determining the desired left bend ratio of jetway hood. Percent
INTERACTIVE POINT JETWAY LEFT DEPLOYMENT [0] Point Name (or index) Interactive Point Jetway constant, determining the desired left deployment angle of jetway hood. Degrees
INTERACTIVE POINT JETWAY RIGHT BEND [0] Point Name (or index) Interactive Point Jetway constant, determining the desired right bend ratio of jetway hood. Percent
INTERACTIVE POINT JETWAY RIGHT DEPLOYMENT [0] Point Name (or index) Interactive Point Jetway constant, determining the desired right deployment angle of jetway hood. Degrees
INTERACTIVE POINT JETWAY TOP HORIZONTAL [0] Point Name (or index) Interactive Point Jetway constant, determining the desired top horizontal ratio of displacement of jetway hood. Percent
INTERACTIVE POINT JETWAY TOP VERTICAL [0] Point Name (or index) Interactive Point Jetway constant, determining the desired top vertical ratio of displacement of jetway hood. Percent
INTERACTIVE POINT GOAL

[0] Point Name (or index)

[1] Value

 The Interactive Point goal percentage of opening (if it's for a door) or percentage of deployment (if it's for a hose or cable). Percent Over 100
INTERACTIVE POINT OPEN

[0] Point Name (or index)

[1] Value

 Interactive Point current percentage of opening (if door) or deployment (if hose/cable). Percent Over 100
INTERACTIVE POINT PITCH [0] Point Name (or index) Interactive Point orientation: Pitch. Degrees
INTERACTIVE POINT POSX [0] Point Name (or index) Interactive Point X position relative to the Datum Reference Point. Feet (ft)
INTERACTIVE POINT POSY [0] Point Name (or index) Interactive Point Y position relative to the Datum Reference Point. Feet (ft)
INTERACTIVE POINT POSZ [0] Point Name (or index) Interactive Point Z position relative to the Datum Reference Point. Feet (ft)
INTERACTIVE POINT TYPE [0] Point Name (or index) The type of interactive point.

Enum:

  1. 0: Main exit
  2. 1: Cargo exit
  3. 2: Emergency exit
  4. 3: Fuel hose
  5. 4: Ground Power cable
  6. 99: Unknown (for error handling)

 

 

Weight

Simulation Variable Description Units Settable
EMPTY WEIGHT Empty weight of the aircraft Pounds (lbs)
EMPTY WEIGHT CROSS COUPLED MOI Empty weight cross coupled moment of inertia Slugs per feet squared (Slug sqft)
EMPTY WEIGHT PITCH MOI Empty weight pitch moment of inertia Slugs per feet squared (Slug sqft)
EMPTY WEIGHT ROLL MOI Empty weight roll moment of inertia Slugs per feet squared (Slug sqft)
EMPTY WEIGHT YAW MOI Empty weight yaw moment of inertia Slugs per feet squared (Slug sqft)
MAX GROSS WEIGHT Maximum gross weight of the aircraft as defined by the max_gross_weight parameter. Pounds (lbs)
MAX LANDING WEIGHT

The maximum weight at which the aircraft is certified to land safely.

Default value will be equal to the MAX TAKEOFF WEIGHT if available, otherwise it will be the MAX GROSS WEIGHT.

 Pounds (lbs)
MAX TAKEOFF WEIGHT

The maximum weight at which the aircraft is certified to comply with all airworthiness requirements.

Default value is the MAX GROSS WEIGHT.

 Pounds (lbs)
MAX ZERO FUEL WEIGHT The maximum weight of the aircraft when fully loaded but with empty fuel tanks as defined by the max_zero_fuel_weight parameter. Pounds (lbs)
TOTAL WEIGHT Total weight of the aircraft Pounds (lbs)
TOTAL WEIGHT CROSS COUPLED MOI Total weight cross coupled moment of inertia Slugs per feet squared
TOTAL WEIGHT PITCH MOI Total weight pitch moment of inertia Slugs per feet squared
TOTAL WEIGHT ROLL MOI Total weight roll moment of inertia Slugs per feet squared
TOTAL WEIGHT YAW MOI Total weight yaw moment of inertia Slugs per feet squared

 

Related Topics

  1. Simulation Variables
  2. Simulation Variable Units
  3. SimvarWatcher