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JSBSim Aerodynamics: Difference between revisions
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→Forces: Minor addition
(→Moments: minor corrections) Tags: Mobile edit Mobile web edit |
(→Forces: Minor addition) Tags: Mobile edit Mobile web edit |
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For purposes of the Aerodynamics section the entire aircraft creates a single, unified aerodynamic force. This force is split into three component vectors. The most common way of splitting this force into vectors is the Lift Drag Side method. Another, potential better way from the perspective of generating a full 360 degree capable [[FDM]], is the Normal, Axial, Side method. | For purposes of the Aerodynamics section the entire aircraft creates a single, unified aerodynamic force. This force is split into three component vectors. The most common way of splitting this force into vectors is the Lift Drag Side method. Another, potential better way from the perspective of generating a full 360 degree capable [[FDM]], is the Normal, Axial, Side method. | ||
* '''Lift: CL''' Lift is the portion of the aerodynamic force that is at a right angle to the relative wind '''and''' lies within the x-z-axis plane (usually the aircraft's symmetry plane) '''and''' is oriented towards the aircraft's upside. (During inverted flight, it points to the ground). | * '''Lift: CL''' Lift is the portion of the aerodynamic force that is at a right angle to the relative wind '''and''' lies within the x-z-axis plane (usually the aircraft's symmetry plane) '''and''' is oriented towards the aircraft's upside. (During inverted flight, it points to the ground). | ||
** Lift is a function of QBar * Wing Area * Cl<sub>lift</sub>. Cl<sub>lift</sub> is generally derived from a 2D table as a function of AoA. In the real world it is also a function of the Reynolds and Mach Numbers. | ** Lift is a function of QBar * Wing Area * Cl<sub>lift</sub>. Cl<sub>lift</sub> is generally derived from a 2D table as a function of AoA. In the real world it is also a function of the Reynolds and Mach Numbers. Using QBarUW is more appropriate for CL than the generic QBar. | ||
* '''Drag: CD''' Drag is the portion of the aerodynamic force that is parallel to the relative wind. | * '''Drag: CD''' Drag is the portion of the aerodynamic force that is parallel to the relative wind. | ||
** It is important to ensure all coefficient functions in the drag section remain positive. When drag coefficient functions are negative, drag is effectively acting as thrust opposite the relative wind. | ** It is important to ensure all coefficient functions in the drag section remain positive. When drag coefficient functions are negative, drag is effectively acting as thrust opposite the relative wind. | ||