Spanwise defined components

Ain raft wings

Aerodynamic performance of aircraft mainly depends on (he quality of its wing, design focuses therefore on optimizing this component Using the present shape design method, we illustrate the amount of needed "key curves*’ along wing span which is inevitably needed to describe and vary the wing shape. Figure 59. The key numbers arc just identification names: span of the wing yQ in the w ing coordinate system is a function of a first independent variable 0 < p < 1. the curve y0(p) is key 20. All following parameters arc functions of this wing span, planform and twist axis (keys 21-23), dihedral (24) and actual 3D space span coordinate (25). section twist (26) and a spanwise section thickness distribution factor (27). Finally we select a suitably small number of support airfoils to form sections of this wing. Key 28 defines a blend­ing function 0 < r < 1 which is used to define a mix between the given airfoils, say. at the root, along some main wing portions and at the tip The graphics in Figure 59 shows how the basic airfoils, designed with subsonic or with supersonic leading edges, may be dominating across this wing. Practical designs may require a larger number of input airfoils and a careful tailoring of the section twist to arrive at optimum lift distribution, for a given planform.

Recent updates to the wing generation include a spanwise definition of the previously mentioned 10-25 airfoil parameters as additional key functions, replacing given support air­foils and the blending key 28. Because of an explicit description of each w ing surface point without any interpolation and iteration, other than sectional data arrays describing the exact sur­face may easily be obtained very rapidly with analytical accuracy.

Wings with high lift systems are created using multicomponent airfoils cither for unswept wings with simply their varied deflected 2D configurations as illustrated in Figure 57. or in the more practical case of swept components (Figure 58) rotation axes and flap tracks need to be described as lines and curves in 3D space The clean airfoil configuration of the sy stem is then changed observing the given 3D kinematics.

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