:orphan: .. **************************************************************************** .. CUI .. .. The Advanced Framework for Simulation, Integration, and Modeling (AFSIM) .. .. The use, dissemination or disclosure of data in this file is subject to .. limitation or restriction. See accompanying README and LICENSE for details. .. **************************************************************************** .. _P6DOF_Aerodynamics_Data_Label: P6DOF Aerodynamics Data ======================= Aerodynamics data is composed of two distinct categories -- aero_data_ and aero_component_ blocks. The aero_data_ block includes the aerodynamics produced by the object without any controls input or effects from any movable surfaces/components. There is only one aero_data_ block, although it may contain additional aero_data_ blocks within it that serve as aero sub-modes. An object usually contains multiple aero_component_ blocks, with one of more for each axis of control and/or for each control surface, depending on the level of detail for the model. Each of these command blocks are detailed below. Core Aerodynamics Data (Non-Controls Data) ========================================== This block defines the primary aerodynamics for the vehicle. The data includes one or more geometric parameters as well as multiple stability derivative tables. See :ref:`P6DOF Theory` for information on how this data is used. In addition, this block includes support for "aero modes", which allow a vehicle to have discrete aerodynamic modes, such as a retarded-fall bomb that has two aero modes -- clean and high-drag. .. command:: aero_data ... end_aero_data The geometric data offers two modes: wing-based or reference area. When using wing-based mode, the wing_chord_ft_, wing_span_ft_, and wing_area_sqft_ should be specified. When using reference area mode, the ref_area_sqft_ should be specified. The stability derivative tables are each a function of mach and alpha (angle-of-attack) or mach and beta (angle-of-sideslip), as appropriate. The tables focus on the base, non-controls aerodynamics of the vehicle. The secondary aerodynamics consist of control surface aerodynamics and are defined using aero_component_, which is completely separate from aero_data_. .. parsed-literal:: aero_data wing_chord_ft_ ... wing_span_ft_ ... wing_area_sqft_ ... ref_area_sqft_ ... use_legacy_derivatives_ ... use_reduced_frequency_ ... aero_center_x_ ... aero_center_y_ ... aero_center_z_ ... :command:`cL_alpha_mach_table` ... :command:`cL_alpha_beta_mach_table` ... :command:`cLq_alpha_mach_table` ... :command:`cL_alphadot_alpha_mach_table` ... cd_alpha_mach_table_ ... cd_beta_mach_table_ ... cd_alpha_beta_mach_table_ ... cy_beta_mach_table_ ... cy_alpha_beta_mach_table_ ... cyr_beta_mach_table_ ... cy_betadot_beta_mach_table_ ... cm_alpha_mach_table_ ... cm_alpha_beta_mach_table_ ... cmq_mach_table_ ... cmp_mach_table_ ... cm_alphadot_mach_table_ ... cn_beta_mach_table_ ... cn_alpha_beta_mach_table_ ... cn_betadot_mach_table_ ... cnr_mach_table_ ... cnp_mach_table_ ... cl_beta_mach_table_ ... cl_alpha_beta_mach_table_ ... clp_mach_table_ ... cl_alphadot_mach_table_ ... cl_betadot_mach_table_ ... clr_mach_table_ ... clq_mach_table_ ... aero_mode_ ... end_aero_mode end_aero_data .. command:: wing_chord_ft The mean chord of the wing measured in feet. This should be used along with wing_span_ft_ and wing_area_sqft_. .. command:: wing_span_ft The wing span of the wing measured in feet. This should be used along with wing_chord_ft_ and wing_area_sqft_. .. command:: wing_area_sqft The area of the wing measured in square feet. This should be used along with wing_chord_ft_ and wing_span_ft_. .. command:: ref_area_sqft The aerodynamic reference area of the vehicle measured in square feet. If this is used, wing_chord_ft_, wing_span_ft_ and wing_area_sqft_ should not be used. .. command:: use_legacy_derivatives This should be **true** when using the "legacy" stability derivatives (which are **DEPRECATED** and should not be used in any new development). **Default:** false .. command:: use_reduced_frequency This should be **true** when using the "reduced frequency" stability derivatives. If **false**, the rate derivatives (e.g. :command:`cLq_alpha_mach_table`, :command:`cnr_mach_table`) will be multiplied by their corresponding angular rates. If **true**, the rate derivatives will instead be multiplied by a non-dimensional reduced frequency. For pitching moment and lift coefficient derivatives, the reduced frequency is calculated as the angular rate times the :command:`wing_chord_ft` divided by twice the speed. All other coefficient derivatives use :command:`wing_span_ft` instead of chord. See :ref:`P6DOF Theory` for more information. **Default:** true /////////////////////////////////////////////////////////////////////////////// .. command:: aero_center_x The aerodynamic center (x-axis) of the vehicle relative to the reference point in object coordinates. This "aero-center" is the "aerodynamic reference point" at which aerodynamic forces and moments will be calculated. The typical definition of aerodynamic center (as it relates to longitudinal stability) is the location at which the moment does not change regardless of the angle of attack. Thus, the pitching moment remains constant at that particular point. Hence, the aerodynamic center, rather than the center of pressure, is used in the analysis of longitudinal stability. .. command:: aero_center_y The aerodynamic center (y-axis) of the vehicle relative to the reference point in object coordinates. .. command:: aero_center_z The aerodynamic center (z-axis) of the vehicle relative to the reference point in object coordinates. Lift Derivatives ---------------- .. command:: cL_alpha_mach_table This is a 2-dimensional **regular_table** that outputs the lift coefficient (cL) based on the Mach and angle of attack (alpha), with a table order of Mach-alpha-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. Sample 2-dimensional table:: sample_cL_alpha_mach_table regular_table independent_variable mach precision float 0.000 0.900 1.2 end_independent_variable independent_variable alpha units deg 0.0 18.0 20.0 end_independent_variable dependent_variable precision float 0.0 1.2 1.3 0.0 1.2 1.3 0.0 1.2 1.3 end_dependent_variable end_regular_table end_sample_cL_alpha_mach_table .. command:: cL_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the lift coefficient (cL) based on Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cLq_alpha_mach_table This is a 3-dimensional **regular_table** that outputs the lift coefficient (cL) based on Mach, angle of attack (alpha), and pitch rate (q), with a table order of Mach-alpha-q-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cL_alphadot_alpha_mach_table This is a 3-dimensional **regular_table** that outputs the lift coefficient (cL) based on Mach, angle of attack (alpha), and alpha-dot (the rate of change of alpha), with a table order of Mach-alpha-alphaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. Drag Derivatives ---------------- .. command:: cd_alpha_mach_table This is a 2-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach and angle of attack (alpha), with a table order of Mach-alpha-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cd_beta_mach_table This is a 2-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach and angle of sideslip (beta), with a table order of Mach-beta-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cd_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. Side-Force Derivatives ---------------------- .. command:: cy_beta_mach_table This is a 2-dimensional **regular_table** that outputs the side force coefficient (cy) based on the Mach and angle of sideslip (beta), with a table order of Mach-beta-value. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cy_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the side force coefficient (cy) based on the Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cyr_beta_mach_table This is a 3-dimensional **regular_table** that outputs the side force coefficient (cy) based on the Mach, angle of sideslip (beta), and yaw rate (q), with a table order of Mach-beta-q-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cy_betadot_beta_mach_table This is a 3-dimensional **regular_table** that outputs the side force coefficient (cy) based on the Mach, angle of sideslip (beta), and rate of change of sideslip (beta-dot), with a table order of Mach-beta-betaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. Pitching Moment Derivatives --------------------------- .. command:: cm_alpha_mach_table This is a 2-dimensional **regular_table** that outputs the pitch coefficient (cm) based on the Mach and angle of attack (alpha), with a table order of Mach-alpha-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cm_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the pitch coefficient (cm) based on the Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cmq_mach_table This is a simple table that outputs the pitch damping coefficient due to pitch rate (cmq) based on Mach. When use_legacy_derivatives_ is true, the value will be multiplied by the pitch rate in deg/sec, while when use_legacy_derivatives_ is false (new derivatives are being used), the value will be multiplied by the pitch rate in rad/sec. .. command:: cmp_mach_table This is a simple table that outputs the pitch damping coefficient due to roll rate (cmp) based on Mach. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cm_alphadot_mach_table This is a 2-dimensional **regular_table** that outputs the pitch (damping) coefficient (cm) based on the Mach and the rate of change of alpha (alpha-dot), with a table order of Mach-alphaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. Yawing Moment Derivatives ------------------------- .. command:: cn_beta_mach_table This is a 2-dimensional **regular_table** that outputs the yaw coefficient (cn) based on the Mach and angle of sideslip (beta), with a table order of Mach-beta-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cn_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the yaw coefficient (cn) based on the Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cn_betadot_mach_table This is a 2-dimensional **regular_table** that outputs the yaw coefficient (cn) based on the Mach and rate of change of sideslip angle (beta-dot), with a table order of Mach-betaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cnr_mach_table This is a simple table that outputs the yaw damping coefficient due to yaw rate (cnr) based on Mach. When use_legacy_derivatives_ is true, the value will be multiplied by the yaw rate in deg/sec, while when use_legacy_derivatives_ is false (new derivatives are being used), the value will be multiplied by the yaw rate in rad/sec. .. command:: cnp_mach_table This is a simple table that outputs the yaw damping coefficient due to roll rate (cnp) based on Mach. When use_legacy_derivatives_ is true, the value will be multiplied by the roll rate in deg/sec, while when use_legacy_derivatives_ is false (new derivatives are being used), the value will be multiplied by the roll rate in rad/sec. Rolling Moment Derivatives -------------------------- .. command:: cl_beta_mach_table This is a 2-dimensional **regular_table** that outputs the roll coefficient (cl) based on the Mach and angle of sideslip (beta), with a table order of Mach-beta-value. This derivative may only be used when use_legacy_derivatives_ is true. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cl_alpha_beta_mach_table This is a 3-dimensional **regular_table** that outputs the roll coefficient (cl) based on the Mach, angle of attack (alpha), and angle of sideslip (beta), with a table order of Mach-alpha-beta-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: clp_mach_table This is a simple table that outputs the roll damping coefficient due to roll rate (clp) based on Mach. When use_legacy_derivatives_ is true, the value will be multiplied by the roll rate in deg/sec, while when use_legacy_derivatives_ is false (new derivatives are being used), the value will be multiplied by the roll rate in rad/sec. .. command:: cl_alphadot_mach_table This is a 2-dimensional **regular_table** that outputs the roll coefficient (cl) based on the Mach and the rate of change of angle of attack (alpha), with a table order of Mach-alphaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: cl_betadot_mach_table This is a 2-dimensional **regular_table** that outputs the roll coefficient (cl) based on the Mach and the rate of change of angle of sideslip (beta), with a table order of Mach-betaDot-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: clr_mach_table This is a simple table that outputs the roll damping coefficient due to yaw rate (clr) based on Mach. When use_legacy_derivatives_ is true, the value will be multiplied by the yaw rate in deg/sec, while when use_legacy_derivatives_ is false (new derivatives are being used), the value will be multiplied by the yaw rate in rad/sec. .. command:: clq_mach_table This is a simple table that outputs the roll damping coefficient due to pitch rate (clq) based on Mach. This derivative may only be used when use_legacy_derivatives_ is false. Aero Modes ---------- .. command:: aero_mode ... end_aero_mode Aero modes may be defined to allow a vehicle to have discrete aerodynamic modes, such as a retarded-fall bomb that has two aero modes -- clean and high-drag. Aero modes support all commands that aero data support with the exception of an aero_mode (aero_modes can not be nested within each other). Each aero mode name must be unique for that object. Aero modes are typically changed using sequencers and the :command:`action_change_aero_mode`. If use_reduced_frequency_ or use_legacy_derivatives_ are not explicitly set within an aero_mode_ block, those undefined settings will be set from the settings defined (or left as defaults) by the parent aero_data_ block. .. parsed-literal:: aero_mode wing_chord_ft_ ... wing_span_ft_ ... wing_area_sqft_ ... ref_area_sqft_ ... use_legacy_derivatives_ ... use_reduced_frequency_ ... aero_center_x_ ... aero_center_y_ ... aero_center_z_ ... :command:`cL_alpha_mach_table` ... :command:`cL_alpha_beta_mach_table` ... :command:`cLq_alpha_mach_table` ... :command:`cL_alphadot_alpha_mach_table` ... cd_alpha_mach_table_ ... cd_beta_mach_table_ ... cd_alpha_beta_mach_table_ ... cy_beta_mach_table_ ... cy_alpha_beta_mach_table_ ... cyr_beta_mach_table_ ... cy_betadot_beta_mach_table_ ... cm_alpha_mach_table_ ... cm_alpha_beta_mach_table_ ... cmq_mach_table_ ... cmp_mach_table_ ... cm_alphadot_mach_table_ ... cn_beta_mach_table_ ... cn_alpha_beta_mach_table_ ... cn_betadot_mach_table_ ... cnr_mach_table_ ... cnp_mach_table_ ... cl_beta_mach_table_ ... cl_alpha_beta_mach_table_ ... clp_mach_table_ ... cl_alphadot_mach_table_ ... cl_betadot_mach_table_ ... clr_mach_table_ ... clq_mach_table_ ... end_aero_mode Movable Aerodynamics Data (Control Surface Aero) ================================================ Secondary aerodynamics include aerodynamic effects produced by control surfaces or other components, such as landing gear, that produce aero effects as a function of angle. For example, retractable landing gear produce significant drag when extended (angle of 90 deg) and no drag when retracted (angle of 0 deg). .. command:: aero_component ... end_aero_component The use of aero components can be simple, such as having three "generic" yaw, pitch and roll aero components, or can be more complex and realistic, such as having sixteen specific components: LeftAileron, RightAileron, LeftStabilator, RightStabilator, LeftRudder, RightRudder, LeftSpeedbrake, RightSpeedbrake, LeftFlap, RightFlap, LeftSpoiler, RightSpoiler, NoseLandingGear, LeftLandingGear, RightLandingGear, and ArrestingHook. During runtime, the position of aero components is controlled by the :ref:`P6DOF_Flight_Control_System_Label`. .. parsed-literal:: aero_component type_ ... ref_area_sqft_ ... use_legacy_derivatives_ ... use_reduced_frequency_ ... :command:`cL_angle_alpha_mach_table` ... cd_angle_alpha_mach_table_ ... cd_angle_beta_mach_table_ ... cd_angle_mach_table_ ... cy_angle_beta_mach_table_ ... cm_angle_alpha_mach_table_ ... cmq_angle_mach_table_ ... cn_angle_beta_mach_table_ ... cnr_angle_mach_table_ ... cl_angle_mach_table_ ... cl_angle_alpha_beta_table_ ... clp_angle_mach_table_ ... clq_angle_mach_table_ ... clr_angle_mach_table_ ... :command:`cLFactor_angle_mach_table` ... end_aero_component .. command:: type This sets the name/type of the aero component. The name must be unique within the set of aero components for the given :command:`p6dof_object_type`. .. warning:: In order for an **aero_component** to operate, it must be "connected" to :command:`flight_controls` via the **control_surface** command in :command:`flight_controls`. The **control_surface** name and the **aero_component** type must match exactly and are case-sensitive. .. command:: ref_area_sqft This is the reference aerodynamic area for the aero component. If this is not specified, the wing_area_sqft_ defined in aero_data_ is used. .. command:: cL_angle_alpha_mach_table This is a 3-dimensional **regular_table** that outputs the lift coefficient (cL) based on the Mach, angle of attack (alpha), and control surface angle, with a table order of Mach-alpha-angle-value. Sample 3-dimensional table:: sample_cL_angle_alpha_mach_table regular_table independent_variable mach precision float 0.000 0.900 1.2 end_independent_variable independent_variable alpha units deg 0.0 18.0 20.0 end_independent_variable independent_variable angle units deg -10.0 0.0 10.0 end_independent_variable dependent_variable precision float -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 -1.0 0.0 1.0 end_dependent_variable end_regular_table end_sample_cL_angle_alpha_mach_table .. command:: cd_angle_alpha_mach_table This is a 3-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach, angle of attack (alpha), and angle of the control surface, with a table order of Mach-alpha-angle-value. This derivative should be used when drag is only a function of alpha (not beta). When this derivative is used, **cd_angle_beta_mach_table** and **cd_angle_mach_table** should not be used. .. command:: cd_angle_beta_mach_table This is a 3-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach, angle of sideslip (beta), and angle of the control surface, with a table order of Mach-beta-angle-value. This derivative should be used when drag is only a function of beta (not alpha). When this derivative is used, **cd_angle_alpha_mach_table** and **cd_angle_mach_table** should not be used. .. command:: cd_angle_mach_table This is a 2-dimensional **regular_table** that outputs the drag coefficient (cd) based on the Mach and the angle of the control surface, with a table order of Mach-angle-value. This derivative should be used when drag is a function of both alpha and beta. (Although this function does not include either alpha or beta, it is more appropriate than either the pro-alpha or pro-beta derivatives.) When this derivative is used, **cd_angle_alpha_mach_table** and **cd_angle_beta_mach_table** should not be used. .. command:: cy_angle_beta_mach_table This is a 3-dimensional **regular_table** that outputs the side force coefficient (cy) based on the Mach, angle of sideslip (beta), and angle of the control surface, with a table order of Mach-beta-angle-value.. .. command:: cm_angle_alpha_mach_table This is a 3-dimensional **regular_table** that outputs the pitch coefficient (cm) based on the Mach, angle of attack (alpha), and angle of the control surface, with a table order of Mach-alpha-angle-value. .. command:: cmq_angle_mach_table This is a 2-dimensional **regular_table** that outputs the pitch damping coefficient due to pitch rate (cmq) based on Mach and the angle of the control surface. .. command:: cn_angle_beta_mach_table This is a 3-dimensional **regular_table** that outputs the yaw coefficient (cn) based on the Mach, angle of sideslip (beta), and angle of the control surface, with a table order of Mach-beta-angle-value. .. command:: cnr_angle_mach_table This is a 2-dimensional **regular_table** that outputs the yaw damping coefficient due to yaw rate (cnr) based on Mach and the angle of the control surface. .. command:: cl_angle_mach_table This is a 2-dimensional **regular_table** that outputs the roll coefficient (cl) based on the Mach and angle of the control surface, with a table order of Mach-angle-value. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. .. command:: cl_angle_alpha_beta_table This is a 3-dimensional **regular_table** that outputs the roll coefficient (cl) based on the angle of the attack (alpha), the angle of slideslip (beta) and the angle of the control surface, with a table order of alpha-beta-angle-value. This derivative may only be used when use_legacy_derivatives_ is false. .. command:: clp_angle_mach_table This is a 2-dimensional **regular_table** that outputs the roll damping coefficient due to roll rate (clp) based on Mach and the angle of the control surface. .. command:: clq_angle_mach_table This is a 2-dimensional **regular_table** that outputs the roll damping coefficient due to pitch rate (clq) based on Mach and the angle of the control surface. .. command:: clr_angle_mach_table This is a 2-dimensional **regular_table** that outputs the roll damping coefficient due to yaw rate (clr) based on Mach and the angle of the control surface. .. command:: cLFactor_angle_mach_table This is a 2-dimensional **regular_table** that outputs the lift factor based on the Mach and angle of the control surface, with a table order of Mach-angle-value. The lift factor is multiplied by the calculated lift. It is used for lift reducing components such as spoilers. This is **DEPRECATED** and should not be used in new developments. .. warning:: This derivative is **DEPRECATED** and should not be used for any new development. ///////////////////////////////////////////////////////////////////////////////////////////// Return to :doc:`p6dof_object_types` or :doc:`p6dof_object_type`