1) PLANFORM

The plantform of the wing can be freely chosen by the designer. There are endless possible plantforms, rectangular, elliptical, arrow, or combinations thereof.  The plantform would decisively influence the distribution of lift over the span and the general behaviour of the wing.

The most common forms now, are formed by ellipticals leading edge and a trailing edge, leaving the tips of the wing a little backwards.

area
span
A/R = span x span / area
max chord
min chord
median chord
taper ratio = min chord / max chord
G (location of center of gravity)

2) AIRFOILS

3) LOBULE

4) RELATIVE WASHIN

The relative increase in AoA of airfoils towards the tips is called "washin". Most paragliders will have a degree of washin, which together with arc, increases span-wise tension and helps to prevent asymmetric collapses.

Washin is however quite a rare feature for the majority of aircraft wings, since it increases the possibility of a tip stall - so washout is more common. Hang gliders have "washout" ( a decrease in Angle of Attack (AoA) towards the tips), which helps to avoid tip stalls, and also increases their pitch stability.

The amount of washin and its variation along the span is a difficult parameter to determine, obtainable by theoretical arguments or using standard values from other paraglider models.

5) TRIDIMENSIONAL COMPOSITION

5) PLAN DEVELOPMENT OF SURFACES (MISE A PLAT)

6) PINCES

7) V-RIBS AND INTERNAL STRAPS

9) TRIM (CALAGE)

10) LINE DESIGN

11) RISERS AND SPEEDSYSTEM

One of the projects of Laboratori d'envol is the creation of an own software for the design of paragliders. This task has already started, with a first module (1) for the generation in plant of paraglides with near attack and near escape in elliptics ways. The idea is to carry out a serie of modules programmed in FORTRAN language, with reading of datum from files of text and obtaining of results in the form of files of text and files of drawing .dxf to visualize and to treat with programs conventional of CAD.

Modules in estude:

1- basic generation of planforms
2- optimization of planforms
3- generation of frontal geometry (lobule)
4- generation of aerodynamic profiles
5- study of the longitudinal equilibrium
6- calculation of the geometry 3D
7- geometry and equilibrium of suspension lines
8- fabric patterns
9- ...

Recently I have modified the code with possibility to generate cells of any measure, with variable thicknesses,
and the generation of the frontal lobule of the wing (modules 2 and 3).

The next improvements will be to generate completely the profiles, to describe the relative torsion, and to calculate the global incidence.

One of the interesting points is to draw the exact form of each panel, taking into account its development in
flat surface, the ovalization, the form of the profiles and their relative incidence.

See a sample of the results from the program at present (V 0.2 1-9-2006):


 
Fig 1. Entry data for file para.dat


Fig 2.  Resulting drawing from the wing in plant and elevation. The suspension for the time being shows in
simplified form, without optimizing the ramifications.



Fig 3. Summary parameters of model 002, a paraglide of 43 cells, 29 m2 of surface and 5,22 of aspect ratio. 

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