flight_model.cfg - [HELICOPTER]

If you are modelling a helicopter then this section is essential, and is used - along with the [FUSELAGE_AERODYNAMICS], [MAINROTOR] and [SECONDARYROTOR] sections - to define the flight model, and including these sections usually means there is no need to include data for the [FLIGHT_TUNING], [AERODYNAMICS] and [AIRPLANE_GEOMETRY] sections. It is worth noting, however, that you will need to set up the [TURBOPROP_ENGINE] and [TURBINEENGINEDATA] sections (those that are not flagged as "jet only") of the engines.cfg file as well.

 

[HELICOPTER]

This section is for setting up the various helicopter-specific components of the flight model.

 

The available parameters are:

 

Parameter Description Type Required
low_realism_stability_scale

This table can be used to scale the pitch, roll and yaw stability of the helicopter. This is a legacy parameter, and should only be used when use_modern_surfaces is set to 0 (FALSE).

Default values are: 1, 1, 1

1D table of 3 Floats

(see Data Types for more information)

The table requires the following 3 inputs:

Pitch scale, Roll Scale, Yaw Scale
No
enable_custom_throttles_control

When this parameter is set to 1 (TRUE) you may control the engine throttles directly using the appropriate SimVars, therefor bypassing (essentially disabling) the default internal simulation functionality.

Default value is 0 (FALSE).

Bool No
reference_length The overall length of the helicopter fuselage (excluding rotors), in ft. Float Yes
reference_frontal_area The front facing area of the helicopter fuselage (excluding rotors), in sqft. Float Yes
reference_side_area The lateral facing area of the helicopter fuselage (excluding rotors), in sqft. Float Yes
side_aero_center

The longitudinal position, in feet, from the Datum Reference Point of the helicopter that represents the lateral aerodynamic center.

Default value is 0.

This is a legacy FSX parameter not used in the modern flight model.

Float No
lift_aero_center

The longitudinal position, in feet, from the Datum Reference Point of the helicopter that represents the vertical aerodynamic center.

Default value is 0.

This is a legacy FSX parameter not used in the modern flight model.

Float No
right_trim_scalar

This value scales the lateral cyclic trim position.

Default value is 1.

Float No
front_trim_scalar

This value scales the longitudinal cyclic trim position.

Default value is 1.

Float No
right_trim_step

The right trim increment value.

Default value is 0.005.

Float No
front_trim_step

The front trim increment value.

Default value is 0.005.

Float No
correlator_available

This defines whether the helicopter has a correlator that maps the throttle onto the collective (1, TRUE), or not (0, FALSE).

NOTE: This parameter will no longer work and should not be used. It has been deprecated in favour of collective_to_throttle_correlator parameters.

Default value is 1 (TRUE).

Bool No
governed_pct_rpm_ref

This is the ratio of the rated RPM that the rotor RPM governor will try to achieve, expressed as a Percent Over 100.

Default value is 1.

Float No
governed_pct_rpm_min

This is the ratio of the rated RPM above which the governor will be enabled, expressed as a Percent Over 100. Note that this value cannot be less than zero and negative values will be clamped to 0.

Default value is 0.

Float No
governor_speed_limit

This sets the limit on the maximum speed of throttle movement by the governor. The value given here ia a ratio between 0 and 1, where the limit is calculated as ratio / sec. If set to 0, then there is no limit imposed.

Default value is 1.

Float No
rotor_brake_scalar

With this parameter you can scale the rotor braking torque.

Default value is 1.

Float No
rotor_brake_torque

This value adjusts the rotor braking torque. The value is in ftlbs per ft.

Default value is 600.

Float No
rotor_friction_torque

This value adjusts the speed at which the rotors will slow down after shutting off the engine. The value is in ftlbs per ft.

Default value is 0.

Float No
torque_scalar

With this parameter you can scale the rotor torque effect. NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
tail_rotor_translating_scalar

This parameter scales the tail rotor thrust.NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
disk_roll_animation_scalar

This parameter scales the rotor disk roll animation angle.

Default value is 1.

Float No
disk_pitch_animation_scalar

This parameter scales the rotor disk pitch animation angle.

Default value is 1.

Float No
cyclic_roll_control_scalar

This parameter scales the roll cyclic controls.

Default value is 1.

Float No
cyclic_pitch_control_scalar

This parameter scales the pitch cyclic controls.

Default value is 1.

Float No
pedal_control_scalar

This parameter scales the pedal controls. This is a legacy parameter, and should only be used when use_modern_surfaces is set to 0 (FALSE).

Default value is 1.

Float No
pedal_yaw_control_scalar

This parameter scales the pedal controls. This should only be used when use_modern_surfaces is set to 1 (TRUE).

NOTE: This parameter can be used on legacy aircraft as well, but it will be cumulative with pedal_control_scalar, and so you should only use one or the other.

Default value is 1, which is the value to set to make this parameter not change anything.

Float No
collective_on_rotor_torque_scalar This parameter scales the collective impact on rotor torque.NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.

Default value is 1.

Float No
collective_to_throttle_correlator

Defines the ratio - from 0 to 1 - with which the collective lever control position is added to the twist grip throttle control position. This will then be applied to the engine(s). The actual equation looks like this:

throttle = throttle_control + collective_control * collective_to_throttle_correlator

Note that if the parameter is set to 0 or is omitted (and all other collective-to-throttle parameters are also omitted) then the engine throttle will work as a simple throttle twist grip control.

IMPORTANT: If you use this parameter, then you cannot use collective_to_throttle_correlator_1d or collective_to_throttle_correlator_2d.

Float No
collective_to_throttle_correlator_1d

This defines the relationship between the collective control position and the twist grip throttle. In this case the throttle applied to the engine(s) is calculated as the sum of the twist grip throttle control position and the result of linear interpolation from this table, depending on the collective control position:

throttle = throttle_control + f (collective_control)

There can be between 2 to 7 pairs of values in this table, and if the dimensions of the table are outside of these bounds, this parameter will be ignored. Values should be between 0 and 1.

Note that if the parameter has all values set to 0 or it is omitted (and all other collective-to-throttle parameters are also omitted) then the engine throttle will work as a simple throttle twist grip control.

IMPORTANT: If you use this parameter, then you cannot use collective_to_throttle_correlator or collective_to_throttle_correlator_2d.

1D Table of Floats

(see Data Types for more information)

No
collective_to_throttle_correlator_2d

This is a 2D table where

  • The top row corresponds to the twist grip throttle control position, from 0 to 1
  • The left column corresponds to the collective control position, from 0 to 1
  • All other values correspond to the ratio between these two controls, also from 0 to 1.

Together they define the throttle control for all helicopter engines using a 2D linear interpolation of the given values. This can be used to help maintain nominal rotor RPM when the pilot moves the collective lever. For example:

throttle_correlator_table =
0.0    :0.0    :0.5     :1,
0.0    :0.0    :0.18    :0.36,
0.25   :0.0    :0.26    :0.52,
0.5    :0.0    :0.34    :0.68,
0.75   :0.0    :0.42    :0.84,
1      :0.0    :0.5     :1 ;

This parameter has no default values, but if it is omitted from the CFG file (and all other collective-to-throttle parameters are also omitted), or the size of the table exceeds the maximum permitted size (see the note below) then the engine throttle will work as a simple throttle twist grip control.

NOTE:
- You can have from 3 to N rows (including the top row with the twist grip throttle values)
- You can have from 2 to N columns (including the left column with the collective values).
- The combined number of entries (rows * columns) cannot exceed 49. So you could have, for example, 3 rows and 16 columns (48 entries) but not 5 rows and 10 columns (50 entries).

2D Table of Floats

(see Data Types for more information)

No
collective_move_rate_limit

This sets the limit on the maximum speed of movement by the collective. The value given here is a ratio that must be 0 or greater, where the limit is calculated as ratio / sec. If set to 0, then there is no limit imposed.

Default value is 1.

Float No
stabilizer_cyclic_scale

If a stabilizer is present and enabled, this is the ratio of assistance it will provide the cyclic.

Default value is 0.

Float No
stabilizer_rudder_scale

If a stabilizer is present and enabled, this is the ratio of assistance it will provide the rudder.

Default value is 0.

Float No
engine_internal_moi

This is the internal moment of inertia of the moving parts of one engine for the clutch simulation and the unclutched simulation, in lbs per ft2.

Default value is 0.25.

Float No
clutch_maximum_torque_up

This is the clutch simulation maximum clutch torque when the engine RPM is pulled up, in lbs per ft.

Default value is 1000.

Float No
clutch_maximum_torque_down

This is the clutch simulation maximum clutch torque when the engine RPM is pulled up, in lbs per ft.

Default value is 1000.

Float No
clutch_unclutch_time

The time - in seconds - it takes for the clutch to go from 0% to 100% or from 100% to 0%.

Default value is 20.

Float No
engine_trim_min

Sets the minimum ratio of the engine rated RPM that can be set by the trimmer. Value is between 0 and 1. Note that this value will be used by the DECREASE_HELO_GOV_BEEP and INCREASE_HELO_GOV_BEEP key events.

As an example: if your rated rotor RPM is 1000RPM, setting the min to 0.9 and the max to 1.1 will allow you to set the trimmer to a value between 900RPM and 1100RPM.

Default value is 1.

Float No
engine_trim_max

Sets the maximum ratio of the engine rated RPM that can be set by the trimmer. Value must be 1 or greater (up to "infinity"). Note that this value will be used by the DECREASE_HELO_GOV_BEEP and INCREASE_HELO_GOV_BEEP key events.

As an example: if your rated rotor RPM is 1000RPM, setting the min to 0.9 and the max to 1.1 will allow you to set the trimmer to a value between 900RPM and 1100RPM.

Default value is 1.

Float No
engine_trim_rate

Sets the speed of change of the ratio of the engine rated RPM, calculated as RPM Ratio / sec. Note that this value will be used by the DECREASE_HELO_GOV_BEEP and INCREASE_HELO_GOV_BEEP key events.

Default value is 0.

Float No
assistance_cyclic_pitch_stability_centre

This is used to center the assistance neutral input for the pitch cyclic, in degrees.

NOTE: See the Note On Flight Assistance for additional information.

Default value is -1.15.

Float No
assistance_cyclic_bank_stability_centre

This is used to center the assistance neutral input for the bank cyclic, in degrees.

NOTE: See the Note On Flight Assistance for additional information.

Default value is -5.7.

Float No
assistance_pedal_yaw_stability_centre

This ratio is used to center the assistance neutral input for the pedal.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.15.

Float No
assistance_pedal_yaw_rotation

This is the ratio of the yaw rotation velocity countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 10.

Float No
assistance_pedal_yaw_maxinput

This is the maximum input ratio for all assistance rudder input.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.5.

Float No
assistance_pedal_yaw_integralmax

This is the maximum input ratio for the integral part of the assistance rudder input.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.2.

Float No
assistance_pedal_yaw_integralspeed

This is the ratio of the yaw rotational velocity countering the integral force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 1.

Float No
assistance_cyclic_drotation

This is the ratio of the pitch and bank rotational velocity countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.

Float No
assistance_cyclic_pitch_rotation

This is the ratio of the pitch and pitch angle countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 2.

Float No
assistance_cyclic_bank_rotation

This is the ratio of the pitch and bank angle countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 2.

Float No
assistance_cyclic_forwardspeed

This is the ratio of the forward speed countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.01.

Float No
assistance_cyclic_sidespeed

This is the ratio of the side speed countering the proportional force.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.01.

Float No
assistance_cyclic_integralmax

This parameter defines the maximum stabilization bank or pitch angle integral - in degrees - for horizontal motion, countering the bank angle integral.

NOTE: See the Note On Flight Assistance for additional information.Default value is 5.

Float No
assistance_cyclic_integralspeed

This is the ratio of the horizontal speed for horizontal motion countering the bank angle integral.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.2.

Float No
assistance_cyclic_maxinput

This is the maximum input ratio for all assistance cyclic input.

NOTE: See the Note On Flight Assistance for additional information.Default value is 0.15.

Float No
assistance_cyclic_maxspeed

This is the maximum speed - in ft per second - for the cyclic assistance. At a speed of 0 ft per second, the assistance works at 100%. At the specified maxspeed, or above, the assistance is disabled, and in between it gradually decreases.

NOTE: See the Note On Flight Assistance for additional information.Default value is 100.

Float No
assistance_pedal_maxspeed

This is the maximum speed - in ft per second - for the pedal assistance. At a speed of 0 ft per second, the assistance works at 100%. At the specified maxspeed, or above, the assistance is disabled, and in between it gradually decreases.

NOTE: See the Note On Flight Assistance for additional information.Default value is 133.

Float No
governor_pid

The PID to control the auto throttle governor.

Default values are: 0, 0, 0, 0, 0

1D table of 5 Floats

(see Data Types for more information).

The table requires the following 5 inputs:

Proportional factor,
Integral factor,     Derivative factor,
I boundary,
D boundary

For more information on these PID controller parameters, please see the section on PID Parameters.

No

 

Note On Flight Assistance

The different assistance_ parameters are provided to pre-initialise the PID that is used for assistance, and will only be used when flight assistance is enabled. The way the PID works is that it will converge towards a value which makes it possible to stabilize the helicopter in hover, and it's the assistance_xxxx_xxxx_stability_centre that you can use to pre-initialise the PID. This will make it start directly at the value that stabilizes the helicopter, so it doesn't "search" as much before stabilizing and is more quickly stable. Note too that there are limits to stabilisation, and if you are too off-center it sometimes does not stabilise at all.

 

 

[FUSELAGE_AERODYNAMICS]

This section is for setting up the aerodynamics of a helicopter fuselage.

 

The available parameters are:

 

Parameter Description Type Required
use_modern_surfaces

When this is set to 0, it will tell the simulation to use the "legacy" helicopter flight model. However setting this to 1 will select the modern flight model, based on surfaces and CFD calculations.

Default value is 0.

Float No
drag_force_cf

This is the drag coefficient of the front facing fuselage.

Default value is 0.

Float No
side_drag_force_cf

This is the drag coefficient of the side facing fuselage.

Default value is 0.

Float No
pitch_damp_cf

The pitch damping coefficient.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
pitch_stability_cf

The pitch stability coefficient.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
roll_damp_cf

The roll damping coefficient.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
yaw_damp_cf

The yaw damping coefficient.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
yaw_stability_cf

The yaw stability coefficient.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.Default value is 1.

Float No
hstab_pos_lon

This sets the relative longitudinal position of the horizontal stabiliser, in ft, relative to the Datum Reference Point.

Default value is -20.

Float No
hstab_pos_vert

This sets the relative vertical position of the horizontal stabilizer, in ft, relative to the Datum Reference Point.

Default value is 0.

Float No
hstab_span

This sets the span of the horizontal stabiliser, in ft.

Default value is 5.

Float No
hstab_area

The area of the horizontal stabiliser, in sqft.

Default value is 0.

Float No
hstab_incidence

The angle of incidence of the horizontal stabiliser, in degrees.

Default value is 0.

Float No
hstab_lift_coef

This is the coefficient of the slope of lift over the AoA for the horizontal stabiliser.

Default value is 3.

Float No
vstab_pos_lon

This sets the longitudinal position of the vertical stabiliser, in ft, relative to the Datum Reference Point.

Default value is -20.

Float No
vstab_pos_vert

This sets the relative vertical position of the vertical stabiliser, in ft, relative to the Datum Reference Point.

Default value is 0.

Float No
vstab_span

This sets the span of the vertical stabaliser, in ft.

Default value is 5.

Float No
vstab_area

The area of the vertical stabiliser, in sqft.

Default value is 0.

Float No
vstab_incidence

The angle of incidence of the vertical stabiliser, in degrees.

Default value is 0.

Float No
vstab_lift_coef

This is the coefficient of the slope of lift over the AoA for the vertical stabiliser.

Default value is 3.

Float No
fuselage_rear_diam_scale

This is the scale of the rear end of the fuselage in relation to the main section.

Default value is 0.25.

Float No
fuselage_rear_pos_vert

The vertical position of the rear end of the fuselage in relation to the main section.

Default value is 3.

Float No
fuselage_position

The position of the fuselage centre - in ft - relative to the Datum Reference Point.

Default values are: 0, 0, 0.

1D table of 3 Floats

(see Data Types for more information).

The table requires the following 3 inputs:

z, x, y
No

 

 

[MAINROTOR]

This section is for setting up the main rotor of a helicopter.

 

The available parameters are:

 

Parameter Description Type Required
TailRotor

Sets whether the rotor is a main rotor or a tail rotor. When set to 0, it's a horizontal lifting rotor, and when set to 1 this defines a secondary vertical stabilization rotor.

Default value is 0.

Float No
Position

The position of the rotor center - in ft - relative to the Datum Reference Point.

Default values are: 0, 0, 0.

1D table of 3 Floats

(see Data Types for more information).

The table requires the following 3 inputs:

z, x, y
No
max_disc_angle

This parameter will work in two different ways depending on the use_modern_surfaces setting:

  • 0 (legacy): this is the maximum angle of the disk when cyclic inputs are at 100%
  • 1 (modern): This is the blade beta when cyclic inputs are at 100%

Default value is 5.

Float No
Radius

The radius of the rotor, in ft.

Default value is 0.

Float No
RatedRpm

The rated rotation speed of the rotor, in RPM.

Default value is 0.

Float No
number_of_blades

The number of blades of the rotor.

Default value is 2.

Float No
weight_per_blade

This is the weight of a single blade of the rotor, in lbs.

Default value is 10.

Float No
weight_to_moi_factor

This defines the weight to MOI ratio for a single blade depending on the mass distribution of the blade.

Default value is 0.577.

Float No
inflow_vel_reference

This defines the reference speed of airflow through the rotor, in ft per second.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.

Default value is 20.

Float No
blade_ang_offset

This parameter permits you to align the simulated rotor to the model's visual mesh rotor.

Default value is 0.

Float No
blade_aspect_ratio

This is the aspect ratio of the rotor blade length over width. This is used to determine the width of the rotor within the simulation.

Default value is 20.

Float No
blade_AOA0_lift_slope

This is the slope of the lift coefficient over the AoA for each blade.

Default value is 6.

Float No
blade_AOAStall_lift_slope

This is the slope of the lift coefficient over the AoA for each blade when the blade is stalled.

Default value is 1.

Float No
blade_tip_to_root_lineartwist

This parameter sets the blade twist between tip and root, in degrees.

Default value is 7.

Float No
blade_AOAStall_scaler

This value inversely scales the AoA angle at which the blade will stall, in degrees.

Default value is 1.69.

Float No
blade_AOAStall_power

This value inversely exponentiates the AoA angle at which the blade will stall.

Default value is 2.

Float No
blade_AOA0_inddrag_efficiency

This value defines the lift induced drag coefficient.

Default value is 0.1.

Float No
blade_AOA0_parasiticdrag

This value defines the blade parasitic drag coefficient.

Default value is 0.005.

Float No
blade_thickness_ratio

This defines the rotor blade width over thickness aspect ratio, and permits the simulation to determine the blade thickness.

Default value is 0.05.

Float No
blade_beta_input_max

This value sets the rotor beta at maximum collective input.

Default value is 10.

Float No
blade_beta_input_min

This value sets the rotor beta at minimum collective input.

Default value is 0.

Float No
blade_flap_rigidity

This value defines the blade rigidity coefficient for flapping dynamics, and will be used to generate phase lag.

Default value is 50.

Float No
blade_flap_inertia

This value defines the blade inertia coefficient for flapping dynamics, and will be used to generate phase lag.

Default value is 0.1.

Float No
blade_lowAOADragAddAng

This value defines the angle of AoA below which there will be an increase of drag.

Default value is -100.

Float No
blade_lowAOADragAddForce

This value defines the intensity of the increase of drag at low AoA angles.

Default value is 0.

Float No
blade_hiAOADragAddAng

This value defines the angle of AoA above which there will be an increase of drag.

Default value is 100.

Float No
blade_hiAOADragAddForce

This value defines the intensity of the increase of drag at high AoA angles.

Default value is 0.

Float No
blade_tip_liftscale

This value defines the ratio of the remaining lift at blade tips because of lift lost for induced drag.

Default value is 1.

Float No
coning_ratio_load_factor_one

This value sets the rotor coning ratio when the load factor is one (a load factor of one represents conditions in straight and level flight, where the lift is equal to the weight).

Default value is 0.1.

Float No
coning_ratio_load_factor_two

This value sets the rotor coning ratio when the load factor is two (a load factor of two approximates the load factor during a maneuver like a turn with a 60º bank angle).

Default value is 0.25.

Float No
coning_angle_at_ratio_one

This value defines the rotor coning angle when the coning factor is 1 (in degrees).

Default value is 6.

Float No
input_to_disk_angle_scale

scale of the input on the disc angle to allow for dead zones and trim countering

Default value is 1.

Float No
gyro_precession_scalar

This value permits you to scale the gyroscopic precession of the rotor.

Default value is 1.

Float No
Reverse_rotation

A value of 0 (FALSE) here will maintain the default rotational direction of the helicopter blades, which is clockwise (when viewed from above). Setting this to 1 (TRUE) will reverse that rotation, so anti-clockwise.

Default value is 0.

Bool No
static_pitch_angle

This parameter defines the neutral cyclic input pitch angle, in degrees.

NOTE: This is only valid for "top" rotors, ie: rotors where the TailRotor parameter is set to 0 (FALSE).

Default value is 0.

Float No
static_bank_angle

This parameter defines the neutral cyclic input bank angle, in degrees.

NOTE: This is only valid for "top" rotors, ie: rotors where the TailRotor parameter is set to 0 (FALSE).Default value is 0.

Float No
cyclic_pitch_centre

This parameter describes the rotor axis default deflection, according to the helicopter design. This affects not only the tendency of the helicopter to pitch or roll when hands are free, but also the angular position of its body under the rotor in the flight. Values should be between -1 and 1.

Default value is 0.

Float No
cyclic_bank_centre

This parameter describes the neutral point the of cyclic control (like a default "trimmer"), which basically only affects the tendency of a helicopter to pitch or roll when hands are free. Values should be between -1 and 1.

Default value is 0.

Float No
cycl_y_on_cycl_y

This parameter allows you to reduce how much the cyclic input adjusts the pitch of the rotor blades. By reducing cycl_y_on_cycl_y and increasing cycl_y_on_collective, one can get a duel rotor helicopter (like the Chinook) to pitch forward and backward using a difference in lift between the front and rear rotor.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE).

Default value is 1.

Float No
cycl_y_on_collective

This parameter allows you to increase how much the cyclic input will adjust the collective setting of the rotor blades. By reducing cycl_y_on_cycl_y and increasing cycl_y_on_collective, one can get a duel rotor helicopter (like the Chinook) to pitch forward and backward using a difference in lift between the front and rear rotor.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE).

Default value is 0.

Float No
pedal_on_bank

When set to a value greater than 0, this parameter will allow the pilot to control the bank of the rotor, with the pedals in order to make the helicopter yaw.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE).

Default value is 0.

Float No
pedal_on_cycl_x

When set to a value greater than 0, this parameter will allow the pilot to control the pitch of the rotor, with the pedals in order to make the helicopter yaw (For helicopters that have 2 main rotors that are one over the other, creating more drag on one rotor while reducing drag on the rotor spinning in the opposite direction, will yaw the helicopter).

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE).

Default value is 0.

Float No
pedal_on_collective

When set to a value greater than 0, this parameter will allow the pilot to yaw the helicopter using rotor drag.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE).

Default value is 0.

Float No

 

 

[SECONDARYROTOR]

This section is for setting up the secondary rotor of a helicopter.

 

The available parameters are:

 

Parameter Description Type Required
TailRotor

Sets whether the rotor is a main rotor or a tail rotor. When set to 0, it's a horizontal lifting rotor, and when set to 1 this defines a secondary vertical stabilization rotor.

Default value is 0.

Float No
Position

The position of the rotor center - in ft - relative to the Datum Reference Point.

Default values are: 0, 0, 0.

1D table of 3 Floats

(see Data Types for more information).

The table requires the following 3 inputs:

z, x, y
No
max_disc_angle

This parameter will work in two different ways depending on the use_modern_surfaces setting:

  • 0 (legacy): this is the maximum angle of the disk when cyclic inputs are at 100%
  • 1 (modern): This is the blade beta when cyclic inputs are at 100%

Default value is 5.

Float No
Radius

The radius of the rotor, in ft.

Default value is 0.

Float No
RatedRpm

The rated rotation speed of the rotor, in RPM.

Default value is 0.

Float No
number_of_blades

The number of blades of the rotor.

Default value is 2.

Float No
weight_per_blade

This is the weight of a single blade of the rotor, in lbs.

Default value is 10.

Float No
weight_to_moi_factor

This defines the weight to MOI ratio for a single blade depending on the mass distribution of the blade.

Default value is 0.577.

Float No
inflow_vel_reference

This defines the reference speed of airflow through the rotor, in ft per second.

NOTE: This parameter will only be used when the use_modern_surfaces parameter is set to 0.

Default value is 20.

Float No
blade_ang_offset

This parameter permits you to align the simulated rotor to the model's visual mesh rotor.

Default value is 0.

Float No
blade_aspect_ratio

This is the aspect ratio of the rotor blade length over width. This is used to determine the width of the rotor within the simulation.

Default value is 20.

Float No
blade_AOA0_lift_slope

This is the slope of the lift coefficient over the AoA for each blade.

Default value is 6.

Float No
blade_AOAStall_lift_slope

This is the slope of the lift coefficient over the AoA for each blade when the blade is stalled.

Default value is 1.

Float No
blade_tip_to_root_lineartwist

This parameter sets the blade twist between tip and root, in degrees.

Default value is 7.

Float No
blade_AOAStall_scaler

This value inversely scales the AoA angle at which the blade will stall, in degrees.

Default value is 1.69.

Float No
blade_AOAStall_power

This value inversely exponentiates the AoA angle at which the blade will stall.

Default value is 2.

Float No
blade_AOA0_inddrag_efficiency

This value defines the lift induced drag coefficient.

Default value is 0.1.

Float No
blade_AOA0_parasiticdrag

This value defines the blade parasitic drag coefficient.

Default value is 0.005.

Float No
blade_thickness_ratio

This defines the rotor blade width over thickness aspect ratio, and permits the simulation to determine the blade thickness.

Default value is 0.05.

Float No
blade_beta_input_max

This value sets the rotor beta at maximum collective input.

Default value is 10.

Float No
blade_beta_input_min

This value sets the rotor beta at minimum collective input.

Default value is 0.

Float No
blade_flap_rigidity

This value defines the blade rigidity coefficient for flapping dynamics, and will be used to generate phase lag.

Default value is 50.

Float No
blade_flap_inertia

This value defines the blade inertia coefficient for flapping dynamics, and will be used to generate phase lag.

Default value is 0.1.

Float No
blade_lowAOADragAddAng

This value defines the angle of AoA below which there will be an increase of drag.

Default value is -100.

Float No
blade_lowAOADragAddForce

This value defines the intensity of the increase of drag at low AoA angles.

Default value is 0.

Float No
blade_hiAOADragAddAng

This value defines the angle of AoA above which there will be an increase of drag.

Default value is 100.

Float No
blade_hiAOADragAddForce

This value defines the intensity of the increase of drag at high AoA angles.

Default value is 0.

Float No
blade_tip_liftscale

This value defines the ratio of the remaining lift at blade tips because of lift lost for induced drag.

Default value is 1.

Float No
coning_ratio_load_factor_one

This value sets the rotor coning ratio when the load factor is one (a load factor of one represents conditions in straight and level flight, where the lift is equal to the weight).

Default value is 0.1.

Float No
coning_ratio_load_factor_two

This value sets the rotor coning ratio when the load factor is two (a load factor of two approximates the load factor during a maneuver like a turn with a 60º bank angle).

Default value is 0.25.

Float No
coning_angle_at_ratio_one

This value defines the rotor coning angle when the coning factor is 1 (in degrees).

Default value is 6.

Float No
input_to_disk_angle_scale

scale of the input on the disc angle to allow for dead zones and trim countering

Default value is 1.

Float No
gyro_precession_scalar

This value permits you to scale the gyroscopic precession of the rotor.

Default value is 1.

Float No
Reverse_rotation

A value of 0 (FALSE) here will maintain the default rotational direction of the helicopter blades, which is clockwise (when viewed from above). Setting this to 1 (TRUE) will reverse that rotation, so anti-clockwise.

Default value is 0.

Bool No
static_pitch_angle

This parameter defines the neutral cyclic input pitch angle, in degrees.

Default value is 0.

Float No
static_bank_angle

This parameter describes the neutral point the of cyclic control (like a default "trimmer"), which basically only affects the tendency of a helicopter to pitch or roll when hands are free.

Default value is 0.

Float No
cyclic_pitch_centre

This parameter describes the rotor axis default deflection, according to the helicopter design. This affects not only the tendency of the helicopter to pitch or roll when hands are free, but also the angular position of its body under the rotor in the flight.

Default value is 0.

Float No
cyclic_bank_centre

This parameter describes the neutral point the of cyclic control (like a default "trimmer"), which basically only affects the tendency of a helicopter to pitch or roll when hands are free.

Default value is 0.

Float No
cycl_y_on_cycl_y

This parameter allows you to reduce how much the cyclic input adjusts the pitch of the rotor blades. By reducing cycl_y_on_cycl_y and increasing cycl_y_on_collective, one can get a duel rotor helicopter (like the Chinook) to pitch forward and backward using a difference in lift between the front and rear rotor.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE) for both the Main and Secondary rotor, ie: it is a dual rotor helicopter.

Default value is 1.

Float No
cycl_y_on_collective

This parameter allows you to increase how much the cyclic input will adjust the collective setting of the rotor blades. By reducing cycl_y_on_cycl_y and increasing cycl_y_on_collective, one can get a duel rotor helicopter (like the Chinook) to pitch forward and backward using a difference in lift between the front and rear rotor.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE) for both the Main and Secondary rotor, ie: it is a dual rotor helicopter.

Default value is 0.

Float No
pedal_on_bank

When set to a value greater than 0, this parameter will allow the pilot to control the bank of the rotor, with the pedals in order to make the helicopter yaw.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE) for both the Main and Secondary rotor, ie: it is a dual rotor helicopter.

Default value is 0.

Float No
pedal_on_cycl_x

When set to a value greater than 0, this parameter will allow the pilot to control the pitch of the rotor, with the pedals in order to make the helicopter yaw (For helicopters that have 2 main rotors that are one over the other, creating more drag on one rotor while reducing drag on the rotor spinning in the opposite direction, will yaw the helicopter).

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE) for both the Main and Secondary rotor, ie: it is a dual rotor helicopter.

Default value is 0.

Float No
pedal_on_collective

When set to a value greater than 0, this parameter will allow the pilot to yaw the helicopter using rotor drag.

NOTE: This parameter is only used when your helicopter has the TailRotor parameter set to 0 (FALSE) for both the Main and Secondary rotor, ie: it is a dual rotor helicopter.

Default value is 0.

Float No