Body geometry Coordinate systems The first entries in the geometry section define the coordinate systems for each of the components and assemblies in the model Each component or assembly has an &aseMi or &comPl line defining the origin of its local coordinate system If the coordinate system of the item is to be rotated about an axis other than the y axis of the assembl coordinate system, an &AsEm2 or &Comp2 line is required as wel
Body Geometry • Coordinate systems – The first entries in the geometry section define the coordinate systems for each of the components and assemblies in the model. – Each component or assembly has an &ASEM1 or &COMP1 line defining the origin of its local coordinate system. – If the coordinate system of the item is to be rotated about an axis other than the Y axis of the assembly coordinate system, an &ASEM2 or &COMP2 line is required as well
&ASEMI ASEMX143.0000. ASEMY=250000. ASEMz=-110000 ASCAL=-1 0000 athet=35 0. NoDEa=0. &END &ASEM2APXX=145.25,APYY=250000.APZZ=-10.1300 AHXX=137.7700, AHYY=140.0. AHZz--8563 &END &ASEM1 ASEMX=1350000, ASEMY=140.0000, ASEMZ=8.0000 ASCAL=1.0000, atHET=0.0. NODEA=5 &END &COMP1 COMPX0 0000 COMPY=0. 0000. COMPz=0.0000. CSCal=. 0000 CtHET=0.0. NODEC=5. &END The meanings of the variables are as follows: ASEMX, ASEMY, ASEMZ Origin of the assembly coordinate system in global coordinates (R) ASCAL Scale. If ASCAL is negative a rotation axis other than the y axis must be defined in ASEM2.(R) athet Rotation angle of the assembly in degrees, using the right hand rule, eg downward deflection of a flap on a right wing is positive. The rotation axis is the assembly Y axis unless asCaL is negative. (R) nodea If NODEA is 0, another assembly is defined after this one If NOdEa is 5, this is the last assembly to be defined. D) APXX, APYY, APzz Starting point of the rotation axis in unscaled assembly coordinates(R) AHXX. AHYYAHZZ Ending point of the rotation axis. (R) Corresponding variables in a component block begin with C or COMP rather than A or asem, but have the same meanings
&ASEM1 ASEMX=143.0000, ASEMY=25.0000, ASEMZ=-11.0000, ASCAL=-1.0000, ATHET=35.0, NODEA=0, &END &ASEM2 APXX=145.25, APYY=25.0000, APZZ=-10.1300, AHXX=137.7700, AHYY=140.0, AHZZ=-8.563, &END &ASEM1 ASEMX=135.0000, ASEMY=140.0000, ASEMZ=-8.0000, ASCAL=1.0000, ATHET=0.0, NODEA=5 &END &COMP1 COMPX=0.0000, COMPY=0.0000, COMPZ=0.0000, CSCAL=1.0000, CTHET=0.0, NODEC=5, &END • The meanings of the variables are as follows: ASEMX, ASEMY, ASEMZ Origin of the assembly coordinate system in global coordinates. (R) ASCAL Scale. If ASCAL is negative, a rotation axis other than the Y axis must be defined in ASEM2. (R) ATHET Rotation angle of the assembly in degrees, using the right hand rule, eg downward deflection of a flap on a right wing is positive. The rotation axis is the assembly Y axis unless ASCAL is negative. (R) NODEA If NODEA is 0, another assembly is defined after this one. If NODEA is 5, this is the last assembly to be defined. (I) APXX, APYY, APZZ Starting point of the rotation axis in unscaled assembly coordinates. (R) AHXX, AHYY, AHZZ Ending point of the rotation axis. (R) Corresponding variables in a component block begin with C or COMP rather than A or ASEM, but have the same meanings
Body geometry Panels The basic surface element is called a panel Panels are defined as rectangles a panel that is triangular in shape is actually a rectangle with two corners that coincide Panels may not have zero area Good neighbor relations Poor neighbor relations No gaps between panel Small in areas of small curvature Larger in flatter aeras 1000 panels for wing 1, 500-5000 panels per side for full models warped panel Warped panel
Body Geometry • Panels – The basic surface element is called a panel. – Panels are defined as rectangles. • A panel that is triangular in shape is actually a rectangle with two corners that coincide. – Panels may not have zero area. – No gaps between panel – Small in areas of small curvature – Larger in flatter aeras – 1000 panels for wing – 1,500-5000 panels per side for full models
Body geometry Patch definition The numbers of panels in the rows and columns of the rectangular array forming a patch is constant across the width and height of the patch While patches are considered for convenience to be rectangular in shape they can be distorted in various ways The row and column counts would be constant throughout the patch Columns of panels in a patch are defined y sections
Body Geometry • Patch definition – The numbers of panels in the rows and columns of the rectangular array forming a patch is constant across the width and height of the patch. – While patches are considered for convenience to be rectangular in shape, they can be distorted in various ways. – The row and column counts would be constant throughout the patch. – Columns of panels in a patch are defined by "sections
Body Geometry Patch orientation and point, section and panel numbering Patches have two surfaces. an outside and an inside They are distinguished by the order in which section and basic point data are entered · right hand method patches are generally arranged from nose to tail, and, from bottom to top FwD Panel numbering lower right corner panel of a patch is number 1: number 2 is above it and so on to the to edge of the patch Point and section numbering Numbering then returns to the bottom of the second column and continues
Body Geometry – Patches have two surfaces, an outside and an inside. They are distinguished by the order in which section and basic point data are entered. • right hand method • patches are generally arranged from nose to tail, and, from bottom to top. – Panel numbering • lower right corner panel of a patch is number 1; number 2 is above it; and so on to the to edge of the patch. • Numbering then returns to the bottom of the second column and continues. • Patch orientation and point, section and panel numbering