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JSBSim Aerodynamics: Difference between revisions
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→Effects: Added XML syntax for stall and aero-rp shift mentioned.
(→Metrics: Added xml syntax for metrics) |
(→Effects: Added XML syntax for stall and aero-rp shift mentioned.) |
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== Effects == | == Effects == | ||
* '''Stall''' - A 'stall' is generally regarded as a loss of lift due to flow separation over the top of a wing, however, examination of lift polar for an airfoil over a full 360 degrees shows that significant amounts of lift are NOT lost as the stall occurs. The biggest aerodynamic effect of a stall is a large and rapid increase in drag. | * '''Stall''' - A 'stall' is generally regarded as a loss of lift due to flow separation over the top of a wing, however, examination of lift polar for an airfoil over a full 360 degrees shows that significant amounts of lift are NOT lost as the stall occurs. The biggest aerodynamic effect of a stall is a large and rapid increase in drag. | ||
<syntaxhighlight lang="xml"> | |||
<hysteresis_limits unit="{RAD | DEG}"> | |||
<min> {number} </min> | |||
<max> {number} </max> | |||
</hysteresis_limits> | |||
</syntaxhighlight> | |||
* '''Spin''' - Spins are caused loss of stability in the Yaw Moment axis. A stock [[Aeromatic]] [[FDM]] yaw section does not take alpha into account when calculating the yaw moment. | * '''Spin''' - Spins are caused loss of stability in the Yaw Moment axis. A stock [[Aeromatic]] [[FDM]] yaw section does not take alpha into account when calculating the yaw moment. | ||
* '''Aerodynamic Reference Point''' - JSBSim provides a way to shift the aerodynamic reference point (AeroRP) forward (negative values) and aft (positive) in response to mach, pitch or other influences. Use the tag <aero_ref_pt_shift_x> in the <aerodynamics> section. The value this tag function returns is internally multiplied by the chord entered in the <metrics> section to get the final shift. You could use this by setting the AeroRP to the leading edge of the wing and use a 1D table indexed by mach starting at .25 chord and getting bigger as the mach number increases to simulate mach tuck. | * '''Aerodynamic Reference Point''' - JSBSim provides a way to shift the aerodynamic reference point (AeroRP) forward (negative values) and aft (positive) in response to mach, pitch or other influences. Use the tag <aero_ref_pt_shift_x> in the <aerodynamics> section. The value this tag function returns is internally multiplied by the chord entered in the <metrics> section to get the final shift. You could use this by setting the AeroRP to the leading edge of the wing and use a 1D table indexed by mach starting at .25 chord and getting bigger as the mach number increases to simulate mach tuck. | ||
<syntaxhighlight lang="xml"> | |||
<aero_ref_pt_shift_x> | |||
<function> | |||
{function contents} | |||
</function> | |||
</aero_ref_pt_shift_x> | |||
</syntaxhighlight> | |||
*'''Lift Due To Elevator''' - There are two interrelated effects from elevator deflection, the Force change and the Moment. These have two different coefficients in two different sections of the FDM but should be considered together. The formula is: | *'''Lift Due To Elevator''' - There are two interrelated effects from elevator deflection, the Force change and the Moment. These have two different coefficients in two different sections of the FDM but should be considered together. The formula is: | ||