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LEPARAGLIDING 3.15

USER MANUAL

1. INTRODUCTION

2. GENERAL CONCEPTS

3. FILES ASSOCIATED WITH THE PROGRAM

4. HOW TO WORK WITH THE PROGRAM

5. COMPOSITION OF THE AIRFOIL FILE

6. COMPOSITION OF THE INPUT DATA FILE leparagliding.txt

    SECTION 1: GEOMETRY
    SECTION 2: AIRFOILS
    SECTION 3 : ANCHOR POINTS
    SECTION 4: LIGHTENING IN THE RIBS (RIB HOLES)
    SECTION 5: SKIN TENSION
    SECTION 6: SEWING ALLOWANCE
    SECTION 7: SEWING MARCAGE
    SECTION 8: ESTIMATING THE GENERAL ANGLE OF ATTACK
    SECTION 9: DESCRIPTION OF LINES
    SECTION 10: BRAKES
    SECTION 11: RAMIFICATIONS LENGTH
    SECTION 12: H V and VH RIBS
    SECTION 15: EXTRADOS COLORS
    SECTION 16: INTRADOS COLORS
    SECTION 17: ADITIONAL RIB POINTS
    SECTION 18: ELASTIC LINES CORRECTION
   
SECTION 19: DXF LAYERS NAMES
    SECTION 20: MARKS TYPES
    SECTION 21: JONCS DEFINITION (NYLON RODS)
    SECTION 22: NOSE MYLARS DEFINITION
    SECTION 23: TAB REINFORCEMENTS
    SECTION 24: GENERAL 2D DXF OPTIONS
    SECTION 25: GENERAL 3D DXF OPTIONS
    SECTION 26: GLUE VENTS
    SECTION 27: SPECIAL WINGTIP
    SECTION 28: PARAMETERS FOR CALAGE SPEED AND TRIMER STUDY
    SECTION 29: 3D SHAPING
   
SECTION 30: AIRFOIL THICKNESS MODIFICATION
    SECTION 31: NEW SKIN TENSION

7. RESULTS


Interpretacions of lines labels in lines.txt

8. NEXT DEVELOPMENTS

FIGURE INDEX

Figure 1: How to work with the program
Figure 2: Airfoils definition
Figure 3: Washin
Figure 4: Axes and coordinates
Figure 5. Miribs definition
Figure 6. Parameter of rotation in "ss" paragliders
Figure 7. Parameter delta of rib forced vertical displacement
Figure 8. Hole type 1, ellipse
Figure 9. Hole type 2, ellipse or circle with central strip
Figure 10. Hole type 3 triangle
Figure 11. Skin tension
Figure 12. Ripstop elasticity
Figure 13. Sewing corrections
Figure 14: General AoA estimation
Figure 15: Suspension lines matrix
Figure 16. Brake distribution
Figure 17: Ramifications length
Figure 18. Mini-rib 1 (horizontal strap)
Figure 19. Mini-rib 2 (V-rib)
Figure 20. Mini-rib 3 (full V-rib)
Figure 21. Mini-rib 4 (VH-rib)
Figure 22. Full continous V-ribs type 5 using parabolic holes
Figure 23. Full continous V-ribs type 5 using elliptical holes
Figure 24. V-rib type 6 general diagonal
Figure 25. Extrados colors
Figure 26. Mark types
Figure 27. Joncs definition
Figure 28. Mylar definition
Figure 29. Tabs definition
Figure 30. Glue vents
Figure 31. Vents types
Figure 32. Special wingtips
Figure 33. Calage variation principe
Figure 34. Calage variation cases
Figure 35. Calage graphic
Figure 36. 3D shaping

1. INTRODUCTION


This manual describes the use of LEparagliding created by Laboratori d'envol for the design of paragliders. The author of the program provides no other information as described in the web. There is no warranty for the correct operation of the program. You assume the full consequences of use of the program.

LEparagliding is very "cryptic" to use, "FORTRAN style", but very powerfull. FORTRAN is a programming language aimed at numerical calculation, which means FORmula TRANslation. It is a language that allows us to accurately translate the ideas of geometry and mathematics to a code that produces amazing graphical and numerical results.

The program implements the theoretical developed in the book "Paraglider Design Handbook", which is advisable to study, because many of the contents are complementary.

I apologize, because this manual provides explanations in a style slightly rough. It is possible that some subjects are poorly explained. I will be happy to provide further clarification by pm. The program is not perfect, but it works.

Please, forgive my writings in English, not good enough, beacuse is not my usual language!


2. GENERAL CONCEPTS


LEparagliding is a calculation engine written in GNU FORTRAN language, that performs the reading the data of the input files, and writes the results to the output files.
 

    Input files:

        leparagliding.txt

Contains detailed geometric definition of the entire paraglider. The designer must edit this text file to achieve the desired results.

        airfoil1.txt
        airfoil2.txt
        ...

They contains coordinate files of the profiles, taking a unit chord. Can be assigned a specific profile name of each rib. However the most common is a general airfoil aplied to tthe entire wing and a zero thickness airfoil for the last profile of the wingtip,

Output files:

        leparagliding.dxf

Contains drawings in DXF format to be visualized. analyzed and edited with a CAD program (LibreCAD, Autocad, Microstation...)

        lep-3d.dxf


Dxf file created automatically by the program and contains 3D model (use 3D CAD program to view)

        lep-out.txt

Text output file with the main parameters calculated on the wing (span, area, aspect ratio, finenesse, ...) and the ordered list of the lengths of all lines in the wing (main line plans and brakes).

        lines.txt

Text output file including the list of all lines labeled in a human readable format
.


3. FILES ASSOCIATED WITH THE PROGRAM

    leparagliding.f

File program source code, written in language "GNU Fortran 77". This file is not necessary for the end user. Is included for developers who want to make modifications, improvements and extensions to the code, or for students. These changes are completely free under the principles and conditions of the GNU General Public License 3.0 (http://www.gnu.org) which is distributed the program.

The author of the file leparagliding.f program keeps it evolving and improving, as are several important aspects to implement and enlarge the use and possibilities of the program. Adjustments are also made to particular designs.

    leparagliding.txt

Text file that contains the main geometric definition of the glider model, whose detailed description is made below.

    gnua.txt, gnuat.txt

Text files containing the coordinates of the profile used. There may be many files you want to use many different profiles (possible apply a different profile in each rib, although that is not common)

    lep-X.XX.out (Linux) or lep-X-XX.exe (Windows)

Executable program that must be activated to read the data and obtain graphical and numerical results. Where X.XX is the numericat index of the version. The name can have a suffix specifying the version of the operating system for which it has been compiled.

    leparagliding.dxf

Dxf file created automatically by the program and contains all drawings of the wing panels with patterns ready to print or further postprocess in a CAD program.

    lep-3d.dxf

Dxf file created automatically by the program and contains 3d model.

    lep-out.txt

Text file with the numerical results of the program.

     lines.txt

Text output file including the list of all lines labeled in a human readable format.
Note that some paragliders require experimental adjustments of the lengths of the lines compared the theoretically calculated (BHL1 is the case).

    lep-3d-surface.dxf

Dxf file created automatically by the program and contains 3d model of the wing surface including ballonement. Still not active.

    lep-3d-surface.stl

STL file created automatically by the program and contains 3d model of the wing surface including ballonement. STL file format will be used to visualize in 3D modelling programs like OpenSCAD and FreeCAD. Still not active.
 

4. HOW TO WORK WITH THE PROGRAM

Working with LEparagliding consists of the following phases:

    1. Pre-process

It is the initial phase of design, whether using CAD or pencil and graph paper and calculator. It defines the shape in plan, the lobe or vault and the desired inclination of the ribs. Note that the pre-process work with paper, pencil, calculator and definition of discrete analytic functions, enables the same precision as with CAD.

An analytical pre-processor
is available (is optional, and
not strictly necessary), but very practical.

    2. Edit data file

    Descibed below in detail. Complete sections 1 to 31. It is the most important operation, and the overall design of the glider itself

    3. Program execution (seconds)

   GNU/Linux: run ./lep-X.XX.out in a terminal

    Windows: execute lep-X.XX.exe including one or more compatible cygwin .dll's in the same directory.

    Mac OSX: compile sorce code in a terminal: " f77 leparagliding.f" and run "./lep-X.XX.out" in terminal as in linux
   (compiler name will be f77, g77, gfortran, or equivalent). Not tested yet.

    4. Viewing the drawings (CAD)

  The program CAD displays the results dxf file. Please use 'zoom_extension' command.

    5. Iteration from stage 1. to achieve the desired layout.

    6. Post-process CAD

    Drawings can be edited by the CAD program to improve the presentation. They should position the panels and ribs on a reference template and print the templates in an array of A4/A3 size paper or plotter.

leparagliding
FIGURE 1: How to work with the program.
Since 2.23 version and additional file lines.txt is in the output.


5. COMPOSITION OF THE AIRFOIL FILES


The file of the profile data must have the following structure:

Line 1: name of the profile (do not use spaces in the name)
Line 2: total number of points defining the profile
Line 3: number of points that form the extrados (upper surface)
Line 4: number of points that form the opening (if any)
Line 5: number of points that form the intrados (lower surface)
Following lines:
X coordinate Y coordinate of each point of the airfoil
The coordinates are ordered starting at the trailing edge, covering the top surface, passed through the leading edge and coming through the lower surface and
again ending at the trailing edge.

Important: The endpoint of the extrados must exactly match the start in% of the opening (air inlet), and the starting point of the intrados must exactly match the end in% of the opening (air outlet). Therefore the airfoil must be processed prior in a CAD program to achieve this. Therefore if you want to vary the start and end points of the air openings  along span, you must detail specific profiles for this. Init and end points of openings declared in leparagliding.txt file must be consistent with the selected airfoils.

airfoil leparagliding
FIGURE 2: Airfoils definition


For gnulab2 two profiles have been defined eg for gnulab2.txt wing and airplan.txt  to the end profile.

It is essential that the number of points of extrados, openings, and intrados, and all are exactly the same for all profiles defined in a wing model.
The maximum number of points allowed per profile is 500.


Zero-thicknees wingtip airfoil:

Usually, you must define a profile of zero thickness for the final profile of the wingtip. It is advisable to move the end of the panel's top surface (upper panel) to 0% of the profile, and keep the same number of points for each item (upper panel "extrados", air intakes, bottom panel "intrados").

Closed cells:

The program apparently only works with open cells. But it also draws all caps cloth inlets that can be added manually (with a CAD program), the underside of the panels. Thus, any cell can be closed or converted to a special opening of any geometric shape. Recent versions have various cell types.


6. COMPOSITION OF THE INPUT DATA FILE leparagliding.txt

Designing the paraglider is simplified to editing the file leparagliding.txt either creating it from scratch or by editing an existing model.

All lines that begin with the symbol "*" are comments that are not used by the program, although you must maintain it to keep the sequence of reading.
It is not allowed to add blank lines.
The main units planned for the data file are centimeters (cm), except sewing allowances in section 6, and some values in section 20 and 21 will be expressed in mm. Optionally, you could use inches and tenths of inches, but this has not been tested ever.

Next, and by section, we define the parameters to enter in the data file. Only are explained the line to complete, because the lines that begin with the asterisk symbol * are comments that should be maintained as are, so that the reading order is right.

First, it indicates the type of data to enter (integer, real , text, or boolean (1 or 0)). Then, following the ":" , indicates the object's data to write. It is essential using the sample file leparagliding.txt to understand. The order, data type, and number of rows is essential for a correct reading of the data file.

SECTION 1: GEOMETRY

By lines, and regardless of the lines beginning with * which are comments or notes for help.

text  :   Brand name (between "  ")
text  :  Wing name (between "  ")
real  :  Drawing scale (1.0 usual value)
real  :   Wing scale (1.0 usual value)
integer :    Cells number
integer :   Ribs number
real, integer, real : Maximum torsion angle (washin) between central airfoil and tips, an integer parameter set to 0-1- 2, and a real number for the angle of attack in the center used only in case "2".

If the integer parameter is set to "0" the washin will be done manually.  (Figure 3).
If the integer parameter is set to "1" then washin will be done proportinal to the chord, being maximun and positive at the tip, using only the first real.
If the integer parameter is set to  "2", then automatic washin angles are set from center airfoil to wingtip. The first real is the washin in wingtip, then set "2", and the last real is the washin in the central airfoil.

Example about how to use: Below line 21 in leparagliding.txt data file:


* Alpha max and parameter
3.5   2  -1.0

- First number "3.5" is the angle of attack (degres) in wingtip airfoil
- Second number "2" is a control parameter that means case "2", ie, add new number indicating the angle of attack of the central airfoil
- Third number "-1.0" is the angle of attack (degres) of the central airfoil

The distribution angles of attack is made proportional to the wing chord (similar to case "1"). See "lep-out.txt" to view the result.

text, boolean : Paraglider type "ds", "ss", or "pc", and parameter set to 0 or 1. If 1 then leading edge triangles will be no rotated (only ss paragliders)
integer + 8 reals:

    For each of the ribs, and considering an orthonormal system of axes XYZ (Figure 4) .
    oriented in the following way:
    X axis along the wingspan
    Y axis along the central chord
    Z axis growing vertical from the wing to the pilot

They are shown in a horizontal line the following parameters:

integer : rib number
real : rib X coordinate
real : Y coordinate of the leading edge
real : Y coordinate of the trailing edge
real : X' coordinate of the rib in its final position in space
real : Z coordinate of the rib in its final position in space
real : the angle "beta" of the rib to the vertical (degres)
real : RP percentage of chord to be held on the relative torsion of the airfoils
real : washin in degrees defined manually (if parameter is set to "0")

These parameters can not be defined without a previous drawing, preferably in a file of computer aided design CAD, in which the desired plant is drawn to an appropriate scale, form lobe in elevation, and inclination of the ribs. This drawing is one of the most basic and important design (pre-process).

It would be possible to generate this drawing by a geometric preprocessor to read basic data from the wing desired number of cells, separation, size, shape, edge and trailing by a few parameters defined to create elliptical shapes. This pre-processor has been implemented (june 2013), but not inside the main program, because we prefer to keep this important part of design with a CAD program, to allow total freedom of the shape of the leading edge, trailing edge, and in the elevation, and inclination of the profiles. Any design is possible, normal wings, or bionic type, with peaks in leading edge or ...

There is a limitation of not being able to define airfoils in the center of symmetry. To remedy this situation can be defined a virtual central cell's with almost zero thickness.

washin
Figure 3. Washin

wing definition
Figure 4. Axis and main paraglider geometric design

Instructions for selecting the type of paraglider (parameters "ds" "ss" "pc" listed above):

"ds": means that the design and calculation parameters are adjusted to create paragliders and parachute of double surface airfoils (intrados and extrados)
"ss":  means that the design and calculation parameters are adjusted to create single skin paragliders and parachutes, Surfaces corresponding to the intrados are not draw. But it is not enough to indicate this parameter to create single skin paraglider. It is necessary to define an special intrados sawtooth profile (or parabolic shaped), so that the vertices of the triangles are located exactly at the point where% is defined the anchor points. As a general rule, we use covers of the air intakes, as part of the sigle skin profile.
"pc": means that the design and calculation parameters are adjusted to create parachutes using double surface airfoils (intrados and extrados).

Maximun alloved number of ribs is 100 per side (200 ribs or 199 cells).

rotated triangles
Figure 5. 
Only in "ss" paragliders, the parameter set to 0 or 1. If "1" then leading edge triangles will be no rotated. Control over specified ribs will be done using a real parameter 0.0 or 1.0 in last column of section 2, as explained below.

SECTION 2: AIRFOILS

In an orderly manner for each rib, are written in a horizontal line:

integer : Number of rib
text : Name the file containing the airfoil assigned to that rib
real : Percentage of chord start of the air inlet
real : Percentage of chord end of the air  inlet
boolean : Value 1 or 0 to create closed cells, at the left of rib ("0" indicates closed-cell, "1" open)
real : Displacement in cm of the rib perpendicular to the chord, and in the plane of the rib itself. Serves to improve the position of the ribs without suspension lines. Value is usually 0
real: Relative weight of the chord, in relation to the load. Value is usually 1.
real:
It has two meanings:

1) If values is "0" or "1", only used in single skin paragliders (useless in double skin). More control in rotation of triangles. Real value "1" (or "1.") means that the triangles are rotated automatically in the corresponding profile. "0" means that the triangles are not rotated, but they are set according to the angle "beta" specified in Section 1.

2)
If the numerical value greater than 1.0 is possible define and draw trailing edge "miniribs" ("minicabs") in non "ss" paragliders: The value, simply define the minirib length (in %).

miniribs minicabs
                Figure 6. Miribs definition in lep  <  2.50 (since lep-2.50 minirib "i" was defined at LEFT, between "i-1" an "i")


Note: init and end points of the air openings are not fully implemented yet in the program, and is in the profile itself obliged to include it means of the integer numbers that describe the end of the top surface and the beginning of the intrados (in each airfoil).

MIDDLE UNLOADED RIBS: Added the possibility of using "middle unloaded ribs". Very easy to use: In section "2. AIRFOILS" at the last column use the parameter "100", means to place a complete unloaded rib in the middle of the panel, and the left corresponding rib. Similarly, as defined in the mini-ribs. But the parameter "100" activates a new specific programation. New plan numbered "1-6" with the new middle ribs numbered and marked. These ribs have been reformatted to achieve a perfect match with high precision, with the corresponding panels. In the center of the panels, are marked equidistant points in correspondence with the middle unloaded ribs. In addition, in the 2D-planform (plan "1-1"), also drawn in gray new ribs. Planned to draw in 3D (for reference) but not yet done. Important: To define holes in the ribs (elliptical or circles), add in section "4. AIRFOIL HOLES" a new hole type "11" that is defined exactly as the type "1" (hole type "1" and type "11" are exactly the same but the type "11" used exclusively by the middle unloaded ribs). In this case the initial rib number and end rib number with holes type "11" should be the same, and greater than the maximum number of ribs on one side, for example, use "50" . See the attached example "leparagliding.txt". All new programation in section 9.9 of the source code.

- "Mini-ribs" are redefined, and now in section "2. AIRFOILS" at the last column, if you use the parameter "15", means to place a 15% mini-rib in the middle of the panel, and at the LEFT of the corresponding rib. Previously (lep < 2.50), mini-rib it was placed on the RIGHT. But it is better set at the left, so you can specify a minirib the center of the wing (Mini-rib specified in the left first rib). And this is consistent with the new middle unloaded ribs.

- Applied little optional displacement (to the center of the wing) in the points marking the position of the miniribs. Third parameter in the line of section "7. MARKS" of the datafile. Before, this displacement was set to default to zero.

Delta displacement
Figure 7.
Interpretacion of parameter in sixth column. Parameter "delta" = forced displacement in cm of the rib perpendicular to the chord, and in the plane of the rib itself.

SECTION 3: ANCHOR POINTS

In an orderly manner for each rib, are shown in a horizontal line:

integer : Number of rib
integer : Number of anchors in the rib
real : Anchor position A as% of rib
real : Anchor position B as% of rib
real : Anchor position C as% of the rib
real : Anchor position D as% of rib
real : Anchor position E as% of rib
real : Anchor position F as% of rib

Note: A, B, C, D, E anchorages. F brakes.


SECTION 4: LIGHTENING IN THE RIBS (RIB HOLES)

By Rows:

integer : Number of configurations of lightening
integer : Initial rib for first lightening configuration
integer : Final rib for first lightening configuration
integer : Number of holes for the first lightening configuration

Definition of each hole in a horizontal line. There are three possible types of holes. Type 1 = elliptical holes (including circulars), type 2 = elliptical holes central band, type 3 =  triangular holes with smooth corners.

If the hole is type 1, type in a horizontal line:

integer : 1
real : Distance from LE to hole center in% chord
real : Distance from the center of hole to the chord line in% of chord
real : Horizontal axis of the ellipse as% of chord
real : Ellipse vertical axis as% of chord
real : Rotation angle of the ellipse
real : 0. (not used)
real : 0. (not used)
real : 0. (not used)

hole 1
Figure 8. Hole type 1, ellipse

If the hole is type 2, type in a horizontal line:

integer : 2
real : Distance from LE to hole center in% chord
real : Distance from the center of hole to the chord line in% of chord
real : Horizontal axis of the ellipse as% of chord
real : Ellipse vertical axis as% of chord
real : Rotation angle of the ellipse
real : central strip width
real : 0. (not used)
real : 0. (not used)

Hole 2
Figure 9. Hole type 2, ellipse or circle with central strip

Not use holes type 2 beacuse yet no implemented !

If the hole is type 3, type in a horizontal line:

integer : 3
real : Distance from LE to triangle in% chord
real : Distance from the center of the triangle corner to the chord line in% of chord
real : Traingle base as% of chord
real : Triangle heigth as% of chord
real : Rotation angle of the base
real : Radius of the smoothed corners
real : 0. (not used)
real : 0. (not used)

hole 3
Figure 10. Hole type 3 triangle

Continue:

integer : Initial rib for second lightening configuration
integer : Final rib for second lightening configuration
integer : Number of holes for the second lightening configuration

Definition of each hole in a horizontal line, as before.

And so on... (repeat pattern for all types of lightening configurations)


SECTION 5: SKIN TENSION

The tension of the top surface and lower surface panels is achieved by creating tapers in the panels. The program allows you to define "over-wides" in 6 points along the edge of the panels. The transition between basis points of overwide is linear.

In each of the six lines are defined to indicate consecutively:

real : Distance in% of chord on the leading edge of extrados
real : Extrados over-wide corresponding in % of chord
real : Distance in% of chord on trailing edge
real : Intrados over-wide corresponding in% of chord

sk

                                                                A better explanation >
sk
FIGURE 11: Skin tension

Then add two more lines with the following parameterr (new in leparagliding 2.0):

 real : 0.0114 (strain in mini-ribs).

The justification for this value is obtained from the theory of elasticity. Leave the default value in case of doubt.

Ripstop elasticity
Figure 12. Ripstop elasticity

integer, real : Number of points np, k coeficient 0.0 to 1.0

The justification for this line is complex. There are two possibles interpretations:

First interpretation)

If first number in NOT set to "1000",
the values are used to make adjustments to the shape of the leading edge for easy sewing, using an "antiprecision" method. However is and old feature and actually is not recomended. Study conducted at the request of a manufacturer of paragliders.
The second number is used to adjust the intensity of the modification (1.0=maximal effect, 0.0= no effect).

Justification of the line in the figure below:

sa
Figure 13. Sewing corrections

And the explanation:

When three panels are sewn at the same time, with different curvatures to side... problems may arise:

The left panel (i="izquierda") has a concave curvature, while the right panel (d="derecha") has a convex curvature.

The lengths of seam lines (line dashed) should be exactly the same. However, the outer edge of the fabric, which is 15 mm from the seam line, is shorter in the left case (inner radius) than the right (outer radius). The program calculates the difference in length of the leading edge in the area of "np" points od airfoil of greatest curvature from air inlet (np defined by user).

With the calculated length difference (1d2d-1i2i), the program modifies the plan shape of the left panel, extending its inner side. Thus, when the seam is made, there are fewer problems ...

The second control parameter, "k" between 0. and 1. is the coefficient to be applied to the difference (1d2d-1i2i). Then 0.0 = no effect. 1.0 = total effect. Then sewing corrections:

integer, real : Number of points np, k coeficient 0.0 to 1.0

Another explanation for the same, but in French: Étude des courbures panneaux-nervures (PDF)
Many builders prefer not to take into account this effect, then select the parameter as k=0.0

Second interpretation) Recommended for all designs

Set the parameters of the line to the values:
1000     1.0

First number "1000" (integer) is only a convention than signifies force the program to use maximal precision, reformating panels to achieve accuraccy better than 0.1 mm (lengths differences beetween rib and panels located at left and right).
Second number is a coefficient (real) between 0.0 and 1.0 that sets the intensity of the correction. If coefficient is set to "0.0" then is no correction. If the coefficient is set to "1.0" the accuracy is maximal, aprox < 0.01 mm.

The description of the geometrical problem and the solution, is decribed here.

In file lep-out.txt is a report in section 6, indicating the final lenghts of the panel at left, rib, panel at right, and maximal difference and distorsions in mm.

SECTION 6: SEWING ALLOWANCES

3 reals : Edge seam (mm) in upper panels,  LE, TE
3 reals : Edge seam (mm) in lower panels, LE, TE
real : Edge seam (mm) in ribs
real : Edge seam (mm) in V-ribs

SECTION 7: SEWING MARCAGE

Indicate the spacing in centimeters and the radius of the point, to make marks on ribs and panels to match all items as accurately and thus able to control that there is no slippage during sewing.

real, real, real : marks spacing, point radius, point displacement

SECTION 8: ESTIMATING THE GENERAL ANGLE OF ATTACK

This section defines the basic length of the lines and provides the general draft of the wing, estimating the center of pressure and angle of glide.

Be entered on lines below:

real : Finesse goal, according to the general proportions of the wing.

real : Position of the wing center of pressure estimated as % of central cord

real : Calage in% (distance from the leading edge point to the perpendicular to the central chord from the pilot position)

real : Riser basic length

real : Basic length of lines (maillons - sail)

real : Separation between main carabiners

calage
FIGURE 14: General AoA estimation


SECTION 9: DESCRIPTION OF LINES


  We define the following concepts, per lines:

integer : Control parameter with the following meanings

0 = lower branches lined only by geometric mean of the anchor points
1 = lower branches lined by weighting type 1 (not fully implemented yet)
2 = lower branches lined by weighting type 2 (not fully implemented yet)

integer : Line plans number (2,3,4...)


Denotes the number of plans of lines that start from each of the risers of the glider. Will be considered as many plans as risers. The "plans" do not necessarily have lines in a plan, and may have different alignments anchors in various rows (pyramid lines)


integer : Paths number for first plan

11 integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i19, i11 Ramifications and levels

(i1) number of branches (ramifications) of the path

(i2) branching level 1
(i3) order at level 1

(i4) level of ramification 2
(i5) order at level 2

(i6) level of ramification 3
(i7) order at level 3

(i8) branching level 4
(i9) order at level 4

(i10) anchor line (1 = A, 2 = B, 3 = C, 4 = c 5 = D, 6 = brake)
(i11) anchor rib number

- These are considered the ramifications from to the bottom to up. The main riser are considered the branch level "1", the next line that starts from maillons "2", the one above is the "3" ... and so on.
- Within a branch level are numbered consecutively in the same lines from left to right 1,2,3,
- Path: Is any path through the ramifications, upward, started in the main carabiner and ended in a sail anchor.
- With these definitions, this section should be written the array of lines for each plan
- The first section number indicates the number of planes to be considered.
- The next number indicates the total number of different paths in the plane.
- Each line of the matrix is a "path"
- If there is no level 3 or 4 is denoted by "0"
- It is only allowed up to 4 levels of branching.

integer : Paths number for second plan

11 integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i19, i11 Ramifications and levels
...

Do likewise with the other plans of the paraglider line design. The example of clear matrix writing is exposed in gnuLAB2 data file.

lines

FIGURE 15: Suspension lines matrix


SECTION 10. BRAKES

real : brake lenght

integer : number of paths brake plane

The first number is the length in cm for the main brake cable, and second number indicates the number of paths brake plane.

11 integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i10, i11 Ramifications and levels

Matrix writes like for the rest of the lines, taking into account that now the level "1" corresponds to the main brake cable.

NOTE:  i11 indicates rib number "i", where anchor the top line of the brakes. This number, usually an integer. Nevertheless, some versions ago was added an interesting feature. Is possible define a decimal which means the displacement of the anchoring point between the rib "i" and the rib and "i+1". For example, 8.4 means anchor the line in the trailing edge, between rib 8 and 9, and 40% from the rib 8.

Brakes distribution:

4 real : s1, s2, s3, s4, s5 (lengths along vault and from center wing)

4 real : d1, d2, d3, d4, d5 (lengths increments in brake line)

brake distribution
Figure 16. Brake distribution


SECTION 11. RAMIFICATIONS LENGTH

Indicates the upper branch lengths to the anchors in sail, by rows:

integer, real :  3 , Distance branching from third ramification to sail (l2)

integer, real, real :  4, Distance branching third to sail (l3), Distance beginning of fourth branching to sail (l2)

integer, real :  3, Distance beginning of third brake branch to sail (l2)

integer, real, real : 4, Distance beginning of third brake branch to sail (l3), Distance brakes start fourth branching to sail (l2)

ram
FIGURE 17: Ramifications length

SECTION 12: H V and VH RIBS

integer : mini-ribs number

real, real : x-spacing, y-spacing (when drawing mini-ribs)

Then, for each mini-rib, and in a row:

integer, integer, integer, integer, integer, integer, real, real real, real, real :

with the following meanings,

If it is a mini-rib horizontal ribbon type:

Type 1: Horizontal strap between rib i1 and rib i2


1
Figure 18. Mini-rib 1 (horizontal strap)


Type 2: Diagonal partial V-rib cintered in rib i

2
Figure 19. Mini-rib 2 (V-rib)

Type 3: Diagonal full V-rib centered in rib i

3
Figure 20. Mini-rib 3 (full V-rib

Type 4: "VH-rib" between rib i-1 to i+2

4
Figure 21. Mini-rib 4 (VH-rib)

Type 5: full continous VH-rib centered in rib i

VRF
Figure 22. Full continous V-ribs type 5 using parabolic holes (if t<100%)

VRF
Figure 23. Full continous V-ribs type 5 using elliptical holes (if t>100%)

When using type 5 ribs keep in mind the following:
- The number of anchorages on the rib "i" must be equal to the number of anchors on the right and left, even if they are not used (they can be virtual, ie without lines)
- To define the Type 5 rib, use a number of lines equal to the number of anchors. Example:

1      5       5 1     1 1    60.0    60.0    80.     7.
2      5       5 2     1 1    60.0    60.0    80.     7.
3      5       5 3     1 1    60.0    60.0    80.     7.
4      5       5 4     1 1    60.0    60.0    80.     7.

Type 6: general diagonal "VH-rib" between rib i and rib i+1

Type 6 is a general diagonal. It's very simple. A trapezoidal diagonal ranging from rib number i to rib number i+1. But the rib is totally configurable in size and position. It has been designed to develop competition paragliders CCC types, which need to jump between 4 and 5 cells without lines. But it can also serve to design simplest paragliders, and replacing some of the types of diagonals described above. It is also very useful to define transverse horizontal strips located in all parts of the wing (the tapes have not necessarily coincide with the anchor points).

Type 6
Figure 24 V-rib type 6 general diagonal

Parameters:

n = number of V-rib (consecutive order)
6 = define V-rib "type 6"
i = number of initial rib
x1 = starting position as a percentage of the chord of the profile
h1 = initial height in percent of the local thickness profile
r1 = radius backwards (cm)
r1- = radius forward (cm)
i +1 = number of final rib
x2 = starting position as a percentage of the chord of the profile
h2 = initial height in percent of the local thickness profile
r2+ = radius backwards (cm)
r2- = radius forward (cm)

Type 6 uses 12 parameters, while the other V-ribs types, use only 10 parameters. This is no problem. The program can read the data file correctly. Simply, interpret the scheme. Try and see the results. Type-6 is now working and fully implemented.

Very important: The pieces "Type 6", must be defined consecutively, and line by line. With the following order: From the leading edge to the trailing edge, and from the center of the wing, to the wingtip. That is, first define all the pieces consecutively in rib number "i", before defining pieces in a rib greater than "i".

Ribs Types 11,12,13,14,15,16

Since version 3.14 of the program, six additional VH-rib types can be used, named Type
11,12,13,14,15, and 16. Type 11 is the same as type 1, but absolute definitions of lengths in cm, now are now set in % of the profile chord. The same for type 12 with respect to type 2, and so on until type 16, which is similar to type 6. Types 11 and 1, 12 and 2, 13 and 3, 14 and 4, cannot be combined in the same model. An auxiliary model can be made if necessary.

When you enter the settings to the types 1,2,3,4,5,6, the absolute lengths will be affected by the scaling factor of the wing (before this does not happen). This allows you to scale the wings more uniformly.

Since version 3.14 the graphical presentation of the VH-ribs in 2D has been greatly improved, and ensuring that the reference decimal numbers are not shifted with respect to the pieces, as happened before.  The roman numbers fit much better and its size may be defined in section 20.

Study examples, section 12 is very powerful and allows for almost any type of rib you can imagine. Example:

***************************************************
*    12. H V and VH ribs
***************************************************
24                                                                   > Use 24 VH-ribs
80    150                                                            > X Y spacing
1      11       0 1     1 1     3.5    0       0       0             > VH-rib 1, Type 11
2      11       1 1     2 1     3.5    0       0       0
3      11       2 1     3 1     3.5    0       0       0
4      11       3 1     4 1     3.5    0       0       0
5      11       8 4     9 4     6.0    0       0       0
6      12       3 3     1 1     3.0    7.0    80.     90.            > VH-rib 6, Type 12
7      12       5 3     1 1     3.0    7.0    80.     90.
8      12       7 3     1 1     3.0    7.0    80.     90.
9      12       9 3     1 1     3.0    7.0    80.     90.
10     13       2 4     1 1     3.0    10.0    0.      0.            > VH-rib 10, Type 13
11     13       4 4     1 1     3.0    10.0    0.      0.
12     13       6 4     1 1     3.0    10.0    0.      0.
13     14       2 2     1 1     3.0    7.0    80.     90.            > VH-rib 13, Type 14
14     14       5 2     1 1     3.0    7.0    80.     90.
15     14       8 2     1 1     3.0    7.0    80.     90.
16     14       11 2    1 1     3.0    7.0    80.     90.
17     15       3  1    1 1     60.    50.    81.     2.0            > VH-rib 17 to 20, Type 15
18     15       3  2    1 1     60.    50.    81.     2.0
19     15       3  3    1 1     60.    50.    81.     2.0
20     15       3  4    1 1     60.    50.    81.     2.0
21     16       10 80.  10.     3.  3. 11     75.     85. 8. 8.      > VH-rib 21, Type 16
22     16       11 75.  85.     8.  8. 12     75.     0.  3. 3.
23     16       6  18.  10.     3.  3. 7      18.   100.  5. 5.
24     16       7  18. 100.     5.  5. 8      18.     0.  3. 3.  


SECTION 15: EXTRADOS COLORS

integer : number of ribs with marks

integer, integer : first rib number, number of marks

integer, real, 0. : first mark, distance % from TE, 0.

integer, real, 0. : second mark, distance % from TE, 0.
                                ...

integer, integer : second rib number, number of marks

integer, real, 0. : first mark, distance % from TE, 0.

integer, real, 0. : second mark, distance % from TE, 0.
                                ...
and so on...

colors
Figure 25. Extrados colors

SECTION 16: INTRADOS COLORS

Like extrados colors, works from version >= 2.41. For example, you may write the minimal configuration:

1
1    1
1    0.    0.

SECTION 17: ADITIONAL RIB POINTS

With this option, auxiliary points can be drawn in the ribs.
Typically
to mark mylars, or start and end points of the nylon rods.

integer : number of points

real, real : x-coordinate % of chord, y coordinate % of chord (first point)
                  ....
real, real : x-coordinate % of chord, y coordinate % of chord (last point)


SECTION 18: ELASTIC LINES CORRECTION

Option to estimate the elastic elongation of the lines in normal flight configuration. These elongations are subtracted from strictly geometric length, so that in flight, are the exact lengths of project. Option fully functional but still under development. To calculate the elongation, we take into account the loads on each line, and the rigidly coefficient of each line, the elongation estimated by Hook's law: F = k·dx

real : load in flight (kg)

real, real : % load distribution in 2 lines rib

real, real, real : % load distribution in 3 lines rib

real, real, real, real : % load distribution in 4 lines rib

real, real, real, real, real :  % load distribution in 5 lines rib

integer, real, real, real, realp, d1, d2, d3 where

p = number of lines per rib (p 1 to 5)
d1 = deformation in lower level with 10 kg
d2 = deformation in medium level with 10 kg
d3 = deformation in higher level with 10 kg



If you are using version until 2.60 of leparagliding, you do not need to continue typing, as it will not be considered. If you are using version 2.70 or higher, continue typing more settings.


SECTION 19: DXF LAYER NAMES

This section allows the user to choose some layers names in the DXF files. To facilitate the edition and modification of DXF files. In version 2.75 only the layers "points" "circles" and "triangles" are functional.

By lines, and regardless of the lines beginning with * which are comments or notes for help:

Line 1: integer
integer :   max layers number, now is 10

Line 2: text1  text2
text1:
general layer name (do not change this text)
text2:
default layer name, to choose freely (with character and space restrictions)

Line 3: text1  text2
text1:
line-external (do not change this text)
text2:
layer name for external cuts, to choose freely (with character and space restrictions)

Line 4: text1  text2
text1:
line-sewing (do not change this text)
text2:
layer name for sewing lines, to choose freely (with character and space restrictions)

Line 4: text1  text2
text1:
line-sewing (do not change this text)
text2:
layer name for sewing lines, to choose freely (with character and space restrictions)

Line 5: text1  text2
text1:
points (do not change this text)
text2:
layer name for euclidean unidimensional points, to choose freely (with character and space restrictions)

Line 6: text1  text2
text1:
circles (do not change this text)
text2:
layer name for minicircle points, to choose freely (with character and space restrictions). Minicircles as alternative for points.

Line 7: text1  text2
text1:
triangles (do not change this text)
text2:
layer name for minitriangles, to choose freely (with character and space restrictions). Used is some special marks (tabs).

Line 8: text1  text2
text1:
square (do not change this text)
text2:
layer name for minisquares, to choose freely (with character and space restrictions). Used is some special marks.

Line 9: text1  text2
text1:
text (do not change this text)
text2:
text layer name, to choose freely (with character and space restrictions).

Line 10: text1  text2
text1:
reference (do not change this text)
text2:
reference layer name, to choose freely (with character and space restrictions).

Line 11: text1  text2
text1:
notes (do not change this text)
text2:
notes layer name, to choose freely (with character and space restrictions).

Example:
******************************************************
*       19. DXF layer names
******************************************************
10
general          default
line-external    cutexternal
line-sewing      cutinternal
points           points
circles          circles
triangles        triangle
square           square
text             text
reference        refer
notes            notes


SECTION 20: MARKS TYPES

This section allows the user to choose different types of marking elements in DXF files (one-dimensional points, minicircles, triangles, segments, ...). This is especially useful for laser cutting plotters, and the ability to adapt marking to manufacturer preferences. Remember that leparagliding generates two types of plans, some for use with conventional printer ("print" version), and others for professional use with computerized cutting plotters ("laser" version).

By lines, and regardless of the lines beginning with * which are comments or notes for help:

Line 1: integer
integer
:   max number of different marks, now is 10

Line 2: text integer real real integer real real   (OK)
text: 
typepoint  is the point for general use
integer:
1=constructed point, 2=minicircle - print
real: radius of minicircle in mm - print
real: offset in mm - print
integer: 1=unidimensional, 2=minicircle - laser
real: radius of minicircle in mm - laser
real: offset in mm - laser

Line 3: text integer real real integer real real   (still not used, set defaults)
text: 
typepoint2
integer:
1=unidimensional, 2=minicircle - print
real: radius of minicircle in mm - print
real: offset in mm - print
integer: 1=unidimensional, 2=minicircle - laser
real: radius of minicircle in mm - laser
real: offset in mm - laser

Line 4: text integer real real integer real real   (still not used, set defaults)
text: 
typepoint3
integer:
1=unidimensional, 2=minicircle - print
real: radius of minicircle in mm - print
real: offset in mm - print
integer: 1=unidimensional, 2=minicircle - laser
real: radius of minicircle in mm - laser
real: offset in mm - laser

Line 5: text integer real real integer real real  (OK)
text: 
typevent
integer:
1=two green points, 2=segment, 3=double segment - print
real: points separation or segment in mm - print
real: offset in mm - print
integer: 1=two green points, 2=segment, 3=double segment - laser
real:
points separation or segment in mm - laser
real: offset in mm - laser

Line 6: text integer real real integer real real  (OK)
text: 
typetab
integer:
1=tree orange points, 2=tree orange full control, 3=triangle - print
real: points separation or segment in mm - print
real: offset in mm - print
integer: 1=tree orange points, 2=tree orange full control, 3=triangle - laser
real:
points separation or triangle height in mm - laser
real: offset in mm - laser


Line 7: text integer real real integer real real (still not used, set defaults)
text: 
typejonc
integer:
1=single point, 2=segment, 3=double segment - print
real: points separation or segment in mm - print
real: offset in mm - print
integer: 1=single point, 2=segment, 3=double segment - laser
real:
points separation or segment in mm - laser
real: offset in mm - laser

Line 8: text integer real real integer real real  (still not used, set defaults)
text: 
typeref
integer:
1,2,3 - print
real: dimesion in mm - print
real: offset in mm - print
integer: 1,2,3 - laser
real:
dimension in mm - laser
real: offset in mm - laser

Line 9: text integer real real integer real real  (OK)
text: 
type8 - romano numbering in panels generated using section 29
integer:
1 not used
real:
0.2 spanning from 0.0 to 1.0 means the position of the roman number (0.0 totally to the left and 1.0 totally to the right, normal values 0.2 or 0.5 - print and laser
real:
4.0 means the vertical offset in mm with respect to the baseline. May be positive or negative number - print and laser
integer: 1 not used
real:
0.0 not used
real:
4.4 means the offset in mm between dots of the roman numeral (global size of the roman numerals) - print and laser

Line 10: text integer real real integer real real  (OK)
text: 
type9 -  general numbers size, and roman marks size in ribs,
integer:
1 not used
real: 0.0 not used
real: 7.0 decimal integer numbers size in cm, in leading edge, ribs, trailing edge panels
integer: 1 not used
real:
3.3 means the offset in mm between dots of the roman numeral (global size of the roman numerals) in rod pockets. If set to 0.0 then roman is not drawn
real: 4.5
means the offset in mm between dots of the roman numeral (global size of the roman numerals) in ribs - print and laser

Line 11: text integer real real integer real real  (OK)
text: 
type10 -  general numbers size in VH-ribs, and roman marks size in VH-ribs,
integer:
1 not used
real: 0.0 not used
real: 6.0 decimal integer numbers size in cm, in VH-ribs
integer: 1 not used
real:
0.0 not used
real: 4.5
means the offset in mm between dots of the roman numeral (global size of the roman numerals in VH-ribs) - laser

S20
Figure 26a. Section 20 reference marks. Types 1,2,3,4,5,8,9,10 now fully functional.

S20 typm8
Figure 26b. Type8 marks parameters interpretation

Check that the parameters you use are correct, otherwise the size of the Roman numerals or decimals will not be appropriate. Since version 3.14 is VERY recommended to use this (or similar) example invariant bloc:

******************************************************
*       20. Marks types
******************************************************
10
typepoint   1  0.25  1.2     2  0.3  1.2
typepoint2  1  0.25  1.2     2  0.2  1.2
typepoint3  1  0.25  1.2     2  0.2  1.2
typevent    1  10.   0.0     2  2.0  0.0
typetab     1  10.   0.0     3  2.0  0.0
typejonc    1  10.   0.0     2  2.0  0.0
typeref     1  5.0   1.      1  2.0  0.0
type8       1  0.2   5.0     1  0.0  5.0
type9       1  0.0   7.0     1  3.2  4.5
type10      1  0.0   6.0     1  0.0  3.33



SECTION 21: JONCS DEFINITION (NYLON RODS)

Section is fully functional. Now it is possible to define type 1 and type 2 rods, which are the most used. Type "1" is  rod on the nose with small deflections at both ends, which are completely controllable in position, transition, and depth of deflection, with 8 parameters. Type "2" is straight or arched rod defined to any position within the profile, which can be at any position within the profile, defined by coordinates. The structure of the section is a bit complex, but it has its own logic. The program calculates the rods and shapes of the pockets, which are also fully controllable in widths, with 4 parameters. It is possible to define different rods for each cell, individually or by groups. If you don't need rods, leave the value to "0". In this section we will use the following basic concepts: scheme, bloc (of data), type (of rod), group (of ribs).

The first number in the section is an integer, which we called the "scheme".

The scheme "0" means, not defining any rod. And here ends the section. Easy!

Line 1: integer
if integer = 0 rods are not considered

Example 1: Scheme "0" means do not use rods
*******************************************************
*       21. JONCS DEFINITION (NYLON RODS)
*******************************************************
0

The scheme "1" means use rods type "1" in the nose. At the bottom line write the number of groups. Then write each group consecutively using four lines. This is the detailed structure of the scheme 1:

Line 1: integer
if integer = 0 rods are not considered
if integer = 1 add some others parametes to define and draw rods

Only if first integer is 1 (use joncs "type 1") then add:

Line 2: integer
integer: number of groups to define


Line 3: integer1  integer2  integer3
integer1:
1 (group number 1)
integer2: number of first rib in group 1
integer3:
number of last rib in group 1

Line 4: real1  real2  real3  real4
real1:
extrados init point deflection in % of chord
real2: extrados final point deflection in % of chord
real3: value of max deflection in intrados % of chord
real4: value n of exponent in curve of deflection type y=k·x^n (normaly use n=2.0, parabolic)

Line 5: real1  real2  real3  real4
real1:
intrados init point deflection in % of chord
real2: intrados final point deflection in % of chord
real3: value of max deflection in intrados % of chord
real4: value n of exponent in curve of deflection type y=k·x^n (normaly use n=2.0, parabolic)

Line 6: real1  real2  real3  real4
real1:
line 1, offset (mm) defining the rod (see figure)
real2: line 2, external width of pocket (mm)
real3: line 3, width for rod between sewing lines (mm)
real4: line 4, internal width of pocket (mm)

Lines 7,8,9,10 repeat same definitions for the group 2, and so on until final group.

Note that it is possible to define as many groups as profiles have the wing, and thus define a different rod for each profile. But normally with a group or two it is sufficient for the whole wing.


Example 2: Scheme "1". Using two groups. Group 1 from rib 1 to 15, and group 2 from rib 16 to 19
*******************************************************
*       21. JONCS DEFINITION (NYLON RODS)
*******************************************************
1
2
1 1 15
5.5  10.    1.5   2.0
5.   11.    2.2   2.0
0.0  9.35  6.3  9.35
2   16 19
5.   9.    2.5  2.0
5.   12    3.   2.0
0.0  9.35  6.3 9.35

S21
Figure 27a. Section 21 joncs type 1 used in scheme "1"


The scheme "2":

Starting from version 3.12 of the program, the definition can be extended... :-) Now it is possible to define a more general model, called "scheme 2". In the scheme 2, we can add rods type "1" and many (not limited)  rods type "2 " within the profile. Type 2 are arc-shaped or straight-line rods. If deemed necessary, other types may be added later.

The structure is as follows:

Line 1: integer
integer: 2 means use scheme "2"

Line 2: integer
integer: number of data blocs to define

Line 3: integer1 integer2
integer1: number of data bloc, starting with 1 and increasing by 1 the subsequent bloc
integer2: rod type can be 1 or 2

Line 4: integer
integer: number of groups to define

If integer2 in line3 was 1, then write consecutively the four lines that define the geometry of the rods type 1 (lines 3,4,5,6 from scheme 1) and continue with more four lines for next group.

If integer2 in line3 was 2, then write
consecutively the tree lines that define the geometry of the rods type 2:

Rods type 2
Figure 27b. Rods type 2 (arch or straight line)

Line 5: integer1  integer2  integer3
integer1:
1 (group number 1)
integer2: number of first rib in group 1
integer3:
number of last rib in group 1

Line 6: real1  real2  real3  real4 real5
real1:
x-coordinate of rod starting at point 1 (x1,y1) in % of airfoil chord
real2: y-coordinate of rod starting at point 1 (x1,y1) in % of airfoil chord
real3: x-coordinate of rod ending at point 2 (x2,y2) in % of airfoil chord
real4: y-coordinate of rod ending at point 2 (x2,y2) in % of airfoil chord
real5: max deflection of the arc in % of airfoil chord. If 0.0 draws a straight line

Line 7: real1  real2  real3  real4
real1:
line 1, offset not used and put 0.0 value
real2: line 2, external width of pocket (mm)
real3: line 3, width for rod between sewing lines (mm)
real4: line 4, internal width of pocket (mm)

Continue with next group...

Continue with next bloc of data...

This definition may seem complicated (and it is!) but is understood better with examples and doing tests and seeing the results

Example 3: Comented scheme "2". Using only one data bloc type 2 and two group. Group 1 from rib 1 to 15, and group 2 from rib 16 to 19
*******************************************************
*       21. JONCS DEFINITION (NYLON RODS)
*******************************************************
2                     < scheme 2
1                     < only one bloc
1 2                   < bloc 1 uses rods type 2
2                     < bloc 1 uses two groups
1 1 15                < group 1 from rib 1 to 15
20. 2.  30. -2.0 3.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
0.0  9.35  6.3  9.35  < rod pocket sizes in mm
2 16 20               < group 2 from rib 16 to 20
40. 4.  30. -3.2 0.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
0.0  9.35  6.3  9.35  < rod pocket sizes in mm


Example 4: Comented scheme "2". Using two data blocs and two groups in each bloc.
*******************************************************
*       21. JONCS DEFINITION (NYLON RODS)
*******************************************************
2                     < scheme 2
2                     < use two blocs
1 1                   < first bloc uses rods type 1
2                     < first bloc uses two groups
1 1 15                < group 1 from rib 1 to 15
5.5  10.   1.5   2.0
5.   11.   2.2   2.0
0.0  9.35  6.3  9.35
2   16 19
             < group 2 from rib 16 to 20
5.   9.    2.5   2.0
5.   12    3.    2.0
0.0  9.35  6.3  9.35

2 2                   < second bloc uses rods type 2
2                     < second bloc uses two groups
1 1 15                < group 1 from rib 1 to 15
20. 2.  30. -2.0 3.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
0.0  9.35  6.3  9.35  < rod pocket sizes in mm
2 16 20               < group 2 from rib 16 to 20
40. 4.  30. -3.2 0.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
0.0  9.35  6.3  9.35  < rod pocket sizes in mm

Number of data blocs limited to 20, and number of groups to 100, then a lot of rods in each airfoil!
Test and see the results!

S21
Figure 27c. Rods type 1 (nose reinforcement) and type 2 (arch or straight line)


SECTION 22: NOSE MYLARS DEFINITION

This section allows the user to draw nose mylars.

Line 1: integer
if integer = 0 mylars are not considered
if integer = 1 add some others parametes to define and draw mylars

Example 1:
*******************************************************
*       22. NOSE MYLARS DEFINITION
*******************************************************
0

Example 2:
*******************************************************
*       22. NOSE MYLARS DEFINITION
*******************************************************
1
1
1    1    22
2.   3.0   1.0   13.5   3.   1.

S22
Figure 28. Section 22 nose mylars definition



SECTION 23: TAB REINFORCEMENTS

This section allows the user to draw tab reinforcements. Still not functional. Leave the value to "0".

Line 1: integer
if integer = 0 tab reinforcements are not considered
if integer = 1 add some others parametes to define and tab reinforcements

Example 1:
*******************************************************
*       23. TAB REINFORCEMENTS
*******************************************************
0

Example 2:
*******************************************************
*       23. TAB REINFORCEMENTS
*******************************************************
1
1
1   1   22
2   2   1   5   3
schemes
1   0    p1   p2   p3   p4   p5
2   0    p1   p2   p3   p4   p5
3   0    p1   p2   p3   p4   p5
4   1    p1   p2   p3   p4   p5
5   1    p1   p2   p3   p4   p5


In this data, one group of reinforcements applicable to ribs 1 to 22 is defined. On the tabs A B C D E, the "schemes" 2,2,1,5,3 respectively are applied. The schemes are defined below the word "schemes":
- Scheme 1 (circular sector), parameter "0" means use units in % of chord, and 5 parameters to define the tab. In this case only the radius r.
- Scheme 2 (trapezoidal sector), parameter "0" means use units in % of chord, and 5 parameters to define the tab. In this case r1-,r1+,r2-,r2+,h.
- Scheme 3 (circular sector), parameter "0" means use units in % of chord, and 5 parameters to define the tab. In this case only r-,r+,h,l. The shape of the triangle is calculated automatically taking into account the inclination of the line in space. The length "l" is discounted at the final length of the line.

- Scheme 4 (rectangular sector), parameter "1" means use absolute units in cm, and 5 parameters to define the tab. In this case only r-,r+,h.
- Scheme 5 (circular-triangular sector),
parameter "1" means use absolute units in cm, and 5 parameters to define the tab. In this case only r-,r+,h,l.

S23
Figure 29. Section 23 tab reinforcements

Another example, with two groups, group 1 from ribs 1 to 10, group 2 from 11 to 22. Group 2 uses scheme "1" for all tabs:

*******************************************************
*       23. TAB REINFORCEMENTS
*******************************************************
1
2
1   1   10
2   2   1   5   3
2   11  22
1   1   1   1   1
schemes
1   0    p1   p2   p3   p4   p5
2   0    p1   p2   p3   p4   p5
3   0    p1   p2   p3   p4   p5
4   0    p1   p2   p3   p4   p5
5   1    p1   p2   p3   p4   p5


SECTION 24: GENERAL 2D DXF OPTIONS

This section allows the user to define some colors in the 2D DXF plans.

Line 1: integer
if integer = 0 DXF options set by default
if integer = 1 add some others parameters for DXF

Only if first integer is 1 then add:

Line 2: text1  integer  text2
tex1:
A_lines_color (do not change this text)
integer: color number index for "A" lines
text2: color name (optional text not used)

Line 3: text1  integer  text2
tex1:
B_lines_color (do not change this text)
integer: color number index for "B" lines
text2: color name (optional text not used)

Line 4: text1  integer  text2
tex1:
C_lines_color (do not change this text)
integer: color number index for "C" lines
text2: color name (optional text not used)

Line 5: text1  integer  text2
tex1:
D_lines_color (do not change this text)
integer: color number index for "D" lines
text2: color name (optional text not used)

Line 6: text1  integer  text2
tex1:
E_lines_color (do not change this text)
integer: color number index for "E" lines
text2: color name (optional text not used)

Line 7: text1  integer  text2
tex1:
F_lines_color (do not change this text)
integer: color number index for "F" brake lines
text2: color name (optional text not used)

Example:
*******************************************************
*       24. GENERAL 2D DXF OPTIONS
*******************************************************
1
A_lines_color    1     red
B_lines_color    30    orange
C_lines_color    3     green
D_lines_color    4     cyan
E_lines_color    6     magenta
F_lines_color    5     blue

Note: Remember usual color index numbers for CAD systems:
1= red, 2=yellow, 3=green, 4=cyan, 5=blue, 6=magenta 7=white 8=dark grey 9= grey,... up to 255 depending on your color palette. It is preferable not to use colors with more than two digits.

SECTION 25: GENERAL 3D DXF OPTIONS

This section allows the user to define some colors in the 3D DXF plans. Allows to draw unifilar not ovalized  versions of the surfaces.

Line 1: integer
if integer = 0 DXF options set by default
if integer = 1 add some others parameters for the 3D DXF

Only if first integer is 1 then add:

Line 2: text1  integer  text2
tex1:
A_lines_color (do not change this text)
integer: color number index for "A" lines
text2: color name (optional text not used)

Line 3: text1  integer  text2
tex1:
B_lines_color (do not change this text)
integer: color number index for "B" lines
text2: color name (optional text not used)

Line 4: text1  integer  text2
tex1:
C_lines_color (do not change this text)
integer: color number index for "C" lines
text2: color name (optional text not used)

Line 5: text1  integer  text2
tex1:
D_lines_color (do not change this text)
integer: color number index for "D" lines
text2: color name (optional text not used)

Line 6: text1  integer  text2
tex1:
E_lines_color (do not change this text)
integer: color number index for "E" lines
text2: color name (optional text not used)

Line 7: text1  integer  text2
tex1:
F_lines_color (do not change this text)
integer: color number index for "F" brake lines
text2: color name (optional text not used)

Line 8: text1 integer integer text2
tex1: Extrados (do not change this text)
integer: if set to "0" unifiilar extrados is not drawn, if set to "1" is drawn
integer: color index for the extrados
text 2: optional text with the color name

Line 9: text1 integer integer text2
tex1: Vents (do not change this text)
integer: if set to "0" unifiilar vents is not drawn, if set to "1" is drawn
integer: color index for the vents
text 2: optional text with the color name

Line 10: text1 integer integer text2
tex1: Intrados (do not change this text)
integer: if set to "0" unifiilar intrados is not drawn, if set to "1" is drawn
integer: color index for the intrados
text 2: optional text with the color name

Example:
*******************************************************
*       25. GENERAL 3D DXF OPTIONS
*******************************************************
1
A_lines_color    1     red
B_lines_color    8     grey
C_lines_color    8     grey
D_lines_color    8     grey
E_lines_color    8     grey
F_lines_color    30    orange
Extrados    1    5     blue
Vents       0    1     red
Intrados    1    3     green

SECTION 26. GLUE VENTS

This section allows to automatically "glue" the air inlets (vents) into the panel of extrados, intrados, or to separate them. The vents include sewing edges. The skin tension i the vent is linear and automatically corresponds to that defined at the points correspondingin extrados and intrados.
The vent definition is very easy and intuitive. You have to make a list of two columns. In the first column, the profile number is indicated, and in the second column the corresponding parameter:
1 means glue the vent to the extrados (normally used in paragliders single skin type)
0 means do not glue anywhere (open air inlet). It is drawn apart to define with CAD special air intakes (circles, ellipses, ...)
-1 means glue the vent to the intrados (usually means, closed cell)
-2 means diagonal vent 100% open ant left, glued to intrados
-3 means diagonal vent 100% open alt right, glued to intrados

Line 1: integer
if integer = 0 then end the section and use old vents style (not recommended)
if integer = 1 add some others parameters for precise vents control

Only if first integer is 1 then add N lines,
one for each airfoil number i:

Line i: integer1 integer2
integer1:
airfoil number (cell between airfoil i and airfoil i-1)
integer2: vent parameter (available parameters 1, 0, -1,-2,-3 as explained above)

Examples 1 (use old style):

*******************************************************

*       26. GLUE VENTS
*******************************************************
0

Examples 2 (full vent control):

*******************************************************
*       26. GLUE VENTS
*******************************************************
1  
1    0
2    0
3    1
4   -2
5   -3
...
20  -2
21  -1
22  -1
23  -1

S26
Figure 30. Glue vents

Functional vents in version 3.02:
0 (=open, but print apart for design special vents)
1 (=closed and "glued" to upper surface)
-1 (=closed and "glued" to lower surface)
-2 (=diagonal vent open at left and "glued" to lower surface)
-3 (=diagonal vent open at right and "glued" to lower surface)

vents types
Figure 31: Vents types (version >= 3.02)

SECTION 27 SPECIAL WINGTIPS

It is used for defining wingtips with special shapes:
Section 27
Figure 32. Special wingtip

Line 1:
integer
if integer = 0 do not add wingtip modifications(set by default)
if integer = 1 add some wingtip modifications

Only if first integer is 1 then add:

Line 2: text  real
text:
AngleLE (do not change this text)
real: angle in degrees between
the horizontal and the leading edge in the last cell

Line 3: text  real
text:
AngleTE (do not change this text)
real: angle in degrees between
the horizontal and the trailing edge in the last cell

Example 1:

*******************************************************
*       27. SPECIAL WING TIP
*******************************************************
1
AngleLE 45
AngleTE -7.78

"1" refers to define "type 1" wing tip modifications. It is planned to define several modifications. Type 1 is the simplest.
"AngleLE" is a name not computed. It serves to remember that next we have to write the new angle in degrees between the horizontal and the leading edge in the last cell. It is usual to force the angle of the last cell, and this section allows it to be done without modifying the geometry matrix. Set 45º for example. "AngleTE" is a name not computed for the trailing edge. Set the angle as desired, -7.78º for example.

Example 2:

*******************************************************
*       27. SPECIAL WING TIP
*******************************************************
0


SECTION 28 PARAMETERS FOR CALAGE VARIATION

Study the variations in the riser lengths and calage when applying speed system or trim system. It is interesting to experiment with new calages in prototypes or to define the speed or trim systems.
s28a
Figure 33. Principles of the study of the calage variations.

We study the variations in the riser lengths when applying accelerator (speed system) pivoting in the last riser (most common case), which remains with constant length. For practical purposes we define a negative alpha  angle of pitch increased in N1 spaces gradually, and then we compute  the variations in the line  lengths and calage. We do the same study, assuming a trim system that increases the picth angle in N2 spaces gradually. In this case, the most usual is to consider the constant length A riser and the other variables in length.

The program analyzes a total of 4 cases, depending on the pivot point and if it is reduction or increase in angle:
s28b
Figure 34. Cases a,b,c,d reported in file lep-out.txt

In output file SECTION 7: lep-out.txt we see the tables that relate in detail the variations of angle, with the calage variations, and increments or decrements of length in each riser. It is interesting to experiment with new calages in prototypes or to define the speed or trim systems. Four cases:
a) Speed system pivot in last riser
b) Speed system pivot in first riser
c) Trimer system pivot in first riser
d) Trimer system pivot in last riser

 Example lep-out.txt:
a) Speed system pivot in last riser:
 -------------------------------------------
 i   alpha       A       B       C  Calage
 1     .00     .00     .00     .00   25.00
 2   -1.00   -2.18   -1.29     .00   21.19
 3   -2.00   -4.35   -2.59     .00   17.40
 4   -3.00   -6.52   -3.88     .00   13.66

Column 2 > angle alpha in degrees
Column 3 >
Decrease of length A riser (amount of accelerator) in cm
Column 4 > Decrease of length B riser in cm
Column 5 > Decrease of length C riser in cm = 0 (pivot in C riser)
Column 6 > New calage %

Write data in in SECTION 28 with one or four lines:

Line 1: integer
if integer = 0 do nothing
if integer = 1 do calage study "type 1"

Only if first integer is 1 then add:

Line 2: integer
integer: number of risers to be considered (2,3,4,5 or 6)

Line 3: real1 real2 real3 real4 real5 real6
real1:
% of central chord for riser A (
is not necessary to match anchor position)
...
real6: % of central chord for riser E (
is not necessary to match anchor position)

Line 4: real1 integer1 real2 integer2
real1:
max angle (negative) in degrees set by the speed system

integer1: number of steps in angle for study purpose
real2: max angle (positive) in degrees set by the trim system
integer2: number of steps in angle for study purpose

Example:
*******************************************************
*       28. PARAMETERS FOR CALAGE VARIATION
*******************************************************
1
3
10. 30.35  60  0  0  0
-4 4 5 10
*******************************************************


Explanation:
Set to calage type "1" (first line), only type "1" available
"3" risers to be considered
A=10.%  B=30.35%  C=60%  D=  E=  F=   (set % to be considered)
Speed angle set to -4º and compute in 4 steps
Trim angle set to 5º and compute in 10 steps

s28c
Figure 35. New graphic in plan 2-1 (.dxf output)


SECTION 29 3D SHAPING

The model of 3-Shaping proposed by the Laboratori, consists in making one or two transverse cuts in the upper surface, near the leading edge, and another optional cut on the bottom surface. We will call this model as "type 1". The edges of the transverse cuts will be modified from the straight line into an arc of a circle. In this way, we can "add fabric" lengthwise and we can control the ovalization and the tension in this direction. Ovalization in transverse direction is achieved via the module of skin tension (SECTIONS 5 or 31). In summary, we can control the amount of tissue and tension in transverse and in longitudinal direction near the nose, where the curvatures are greatest.

To set the parameters of the 3D-shaping in the model "type 1" is necessary to study the profile in detail, viewing and counting the individual points that form it, Laboratori style! :-) You need to view your profile in CAD (or in the .txt file), identify and count points. Remember that the points in a profile is counted starting in the trailing edge (point 1), continuing by the upper surface, nose, vents, lower surface, and ending again in the trailing edge. Exactly as described previously. We could define another model "type 2" where the position of the cut points are defined in % of the length of the panel, but in this model 1, is considered to specify exactly the points considered.

For each cut, it is necessary to define a "zone of influence". In the zones of influence is measured the length of a section of the profile and is compared with the corresponding length in the ovalized profile. This question is fundamental to understand the 3D-shaping type 1. It is necessary to view the figure below:

3d
Figure 36. Cuts and zones of influence. J1,j2,j3,j4,j5,j6,j7 indicate numeric values of the selected points in the profile, starting to count from the trailing edge. J4 and j5 are the vent points.

For the purposes of notation, we will call the different parts in which we divide the profile as:
zone 1 (between j1 and j2), extrados part 1
zone
2 (between j2 and j3), extrados part 2
zone
3 (between j3 and j4), extrados part 3 or nose
zone
4 (between j4 and j5), or vents
zone
5 (between j5 and j6), intrados part 1
zone
6 (between j6 and j7), intrados part 2

In each zone 1,2,3,4,5,6 the program computes the length ot the arch of airfoil (d1) and the arch of the ovalized airfoil (d2). The differences of longitude (d2-d1) are calculated automatically in each zone, and then applied consistently to each cut with a value (f) obtained using the values (d2-d1) of the adjacent zones. Is provided a setting parameter around 1.0, which serves the designer to regulate the depth of the 3D-shaping in each cut (positive or negative), in relation to the automatic calculation. Thus, using the coefficient of 1.0, the depth of 3D is according to the theory exposed. Using a coefficient of 0.0 does not apply the 3D effect, and using values higher or lower than 1.0 increases or decreases the effect. The control of the depth of 3D-shaping is continuous and individual for each cut. A more detailed description, and the formulas used in the calculation are described in this technical note about 3D-shaping. For each rib, a full report of the values d1, d2, d2-d1, computed in each zone, and the final values f aplied in each cut are printed in tabular form in section 9 of the file lep-out.txt.
Also, for verification purposes, a new section 10 is written to the lep-out.txt file with the counting of the points of each profile, to verify that they are all the same for all profiles, and that they are compatible with the defined cuts.

It should be noted, that the parameters applied in this section, will be usually "invariant values" applied to the majority of the designs. We just have to think about all this, a single time for each type of profile. And the Laboratory will provide soon the recommended values in next designs. Of course, finding the good parameters is a real art. The program LEparagliding now provides the tools to make numerical and graphical experiments (
lep-out.txt section 9 and leparagliding.dxf plan in box 1-8).

Negative 3D-shaping values are available since version 3.11

Explanation of the parameters in SECTION 29:

Line 1: integer
if integer = 0 then no not use 3D-shaping, and finish writing the section.
if integer = 1 then use 3D-shaping, and continue writing:

Line 2: integer
integer =
type of 3D-shaping theory used, now we use only model "type 1" using transverse cuts, set parameter to 1.

Line 3: character  integer
character = groups
integer1 = number of groups used

Line 4: character  integer1  integer2  integer3
character = group
integer1 = number of the group
integer2 = initial rib in group
integer3 = final rib in group

Line 5: character 
integer1  integer2
character = upper , word meaning upper surface (extrados)
integer1 = number of cuts in upper surface (possible values 1 or 2).
integer2 = subtype of cuts, set to 1, only value accepted

Line 6:
integer1  integer2  real
integer1 = initial point in the first zone of influence (j1)
integer2 = point where the first cut is set (j2)
real = "depth" of 3D-shaping in the cut, possible values -1.0,-0.4,0.0, 0.1,....,1.0,1.2,... (multiplier coefficient around +-1.0)

Line 7: integer1  integer2  real   (only if we use two extrados cuts)
integer1 = initial point in the second zone of influence (j2)
integer2 = point where the second cut is set (j3)
real = "depth" of 3D-shaping in the cut, possible values -1.0,-0.4,0.0, 0.1,....,1.0,1.2,... (multiplier coefficient around +-1.0)

Line 8: character  integer1  integer2
character = lower , word meaning lower surface (intrados)
integer1 = number of cuts in lower surface (possible values 0 or 1).
integer2 = subtype of cuts, set to 1, only value accepted

If the number of cuts in intrados is 0, stop writing, else

Line 9: integer1  integer2  real   (only if we use two extrados cuts)
integer1 = point where the intrados cut is set (j6)
integer2 = final point in the intrados zone of influence (j7)
real = "depth" of 3D-shaping in the cut, possible values -1.0,-0.4,0.0, 0.1,....,1.0,1.2,... (multiplier coefficient around +-1.0)

(...Repeat lines 5,6,7,8,9 for next groups...)

Line 10: character
character =  "
* print parameters:" (comment line, it is mandatory to write something)

Line 11: character  integer1  integer2 integer3  integer4
character = Inter3D, word to indicate representation of the intermediate airfoils in 3D lep-3d.dxf
integer1 = 0 indicates do not draw, and 1 draw
integer2 = index of first airfoil to draw
integer3 = index of last airfoil to draw
integer4 = 0 it indicates to draw with symmetry, 1 only one side

Line 12: character  integer1  integer2 integer3  integer4
character = Ovali3D, word to indicate representation of the intermediate ovalized airfoils in 3D lep-3d.dxf
integer1 = 0 indicates do not draw, and 1 draw
integer2 = index of first airfoil to draw
integer3 = index of last airfoil to draw
integer4 = 0 it indicates to draw with symmetry, 1 only one side

Line 13: character  integer1  integer2 integer3  integer4
character = tesse3D, word to indicate representation of panel tessellation in 3D lep-3d.dxf
integer1 = 0 indicates do not draw, and 1 draw
integer2 = index of first panel to draw
integer3 = index of last panel to draw
integer4 = 0 it indicates to draw with symmetry, 1 only one side

Line 14: character  integer1  integer2 integer3  integer4
character = exteDXF, word to indicate representation of panels tessellation in 3D in a new external DXF file (possible use in CFD analysis)
integer1 = 0 indicates do not draw, and 1 draw
integer2 = index of first panel to draw
integer3 = index of last panel to draw
integer4 = 0 it indicates to draw with symmetry, 1 only one side

Line 15: character  integer1  integer2 integer3  integer4
character = exteSTL, word to indicate representation of panels tessellation in 3D in a new external STL file (used with programs of 3D modelling as OpenSCAD or FreeCAD)
integer1 = 0 indicates do not draw, and 1 draw
integer2 = index of first panel to draw
integer3 = index of last panel to draw
integer4 = 0 it indicates to draw with symmetry, 1 only one side

Lines 12, 13, 14, 15 are mandatory to write, but  the actions are not yet functional. We are working on the programming. These parameters will generate independent dxf files  with the ovalized surfaces, and even a .stl model to view with FreeCAD or OpenSCAD, or even analyze with CFD programs.

All this may seem complicated, but it is much easier to understand section structure watching a few examples:

Example 1: Do not use 3D-shaping. Set one line with "0" parameter and stop writting. It is the simplest solution to avoid the complicated 3D-shaping module! :)

*******************************************************
*       29. 3D SHAPING
*******************************************************
0

Example 2: Active 3D-shaping module but without any cut. The utility of defining this, is that the representation of plan 1-8 is activated automatically, with the drawing of the intermediate and ovalized airfoils in 2D. You can also activate the 3D representations in 3D, changing the settings "0" to "1" in the "Print parameters" subsection. In general, preferable to use example 2, that use the example 1 (the two are invariant sections).

************************************************************
*       29. 3D SHAPING
*******************************************************

1
1
groups  1
group   1    1    1
upper   0    1
lower   0    1
* Print parameters
Inter3D 0    1    1    0
Ovali3D 0    1    1    0
tesse3D 0    1    1    0
exteDXF 0    1    1    0
exteSTL 0    1    1    0

Example 3. Easy case, only one group and one cut in extrados.
First group from rib 1 to 14 using one cuts type 1 in upper surface and zero in lower surface.
Zone of influence of first cut started in point 30 and cut located in point 40,
depth of the effect 0.8.
Zero cuts in lower surface, type 1.
Prints 3D intermediate (Inter3D) and ovalized (Ovali3D) airfoils at the left of ribs 1 to 14

*******************************************************
*       29. 3D SHAPING
*******************************************************
1
1
groups   1
group    1    1   14

upper    1    1
1       30   40   0.8
lower    0    1
* Print parameters
Inter3D 1    1    14    0
Ovali3D 1    1    14    0
tesse3D 0    1    1     0
exteDXF 0    1    1     0
exteSTL 0    1    1     0


Example 4:
General case, using two groups.

First group from rib 1 to 10 using two cuts in upper surface and one in lower surface.
Zone of influence of first cut started in point 25 and cut located in point 33,
depth of the effect 0.8.
Zone of influence of the second cut in point 33 and cut located in point 44, depth of the effect -0.3.
Cut in lower surface in point 79 and zone of influence up to point 84, depth of effect 1.0.

Second group from rib 11 to 14 using two cuts in upper surface and one in lower surface.
Zone of influence of first cut started in point 25 and cut located in point 33,
depth of the effect 0.9.
Zone of influence of the second cut in point 33 and cut located in point 44, depth of the effect 0.9.
Cut in lower surface in point 79 and zone of influence up to point 83, depth of effect 1.0.

*******************************************************
*       29. 3D SHAPING
*******************************************************
1
1
groups   2
group    1    1   10
upper    2    1
1       25   33   0.8
2       33   44  -0.3
lower    1    1
1       79   84   1.0
group    2   11   14
upper    2    1
1       25   33   0.9
2       33   44   0.9
lower    1    1
1       79   83   1.0
* Print parameters
Inter3D 1    1    14    0
Ovali3D 1    1    14    0
tesse3D 0    1    1     0
exteDXF 0    1    1     0
exteSTL 0    1    1     0


The location of the cut points depends mainly on the study of the shape of the profile. It is interesting to concentrate the cuts where the difference in lengths between segments located in the intermediate profile and the ovalized (balloned) profile are larger. As a first approximation, can be studied to place the cuts in the 5.5% and 13.5% of the profile chord, counting from the leading edge. It is also important to choose correctly the coefficient of depth. Theoretically 1.0 is the best, but to smooth out the surfaces, you can choose a smaller coefficient.

As Piet
suggests from the Netherlands, the 3D module can also be used as a simple alternative to separate colored panels in the noses area, or panels with more durable fabric. Remember that the 3D effect is adjustable in depth, and you can even use the parameter amplification 0.0 so that the cut between the parts of the panels is completely straight line. The subroutines developed in this section will be adapted to complete the separation in parts of colors.

The programming of this 3D-shaping module has been made possible thanks to the support of Scott Roberts from USA (Fluid Wings https://www.fluidwings.com/ ).


SECTION 30: AIRFOIL THICKNESS MODIFICATION

Coefficients of amplification or reduction of the thickness of the cells. Normally define as "1.0", or "0.0" in the wingtip.

Line 1:
integer
if integer = 0 then no airfoil amplification set
if integer = 1 then add:

Lines 1,2,3,...,maxrib: integer   real
I
nteger: set rib number (1,2,3...) in all ribs
real: set amplification coefficient, for example 1.0 as default

Example:
*******************************************************
*       30. AIRFOIL THICKNESS MODIFICATION
*******************************************************
1
1    1.2
2    1.1
3    1.0
4    1.0
5    1.0
6    1.0
7    1.0
8    1.0
9    1.0
(...)
23   0.0


SECTION 31: NEW SKIN TENSION

The correct definition of the skin tension is essential for the internal solidity and the flight quality of the apparatus. For this reason, it is recommended that the designer have total control over the skin tension, with a very precise form (law of increments of width), and allowing changes in different panels along the span. This is what allows the new module.

The module new skin tension, functional from version 3.00, defines the additional widths of panels, to achieve the desired ovalitzation. The values applied to the extrados and intrados, for compatibility are the same as those explained in
SECTION 5, but there is a greater control. The number of points to define the widths is not limited to 6, now can be up to 100 points (!) (to choose freely). And it is possible to choose different widths for each one of the ribs, if it is considered necessary, (defining different "groups" of widths). Of course, the number of groups can be equal to the number of ribs, and thereby define the widths of each panel individually (for example, different tension in the panels of the center panels and in the wingtip).

The basic idea is to calculate increments of width to the left and to the right of each rib. Thus, a panel can have a 2% increase maximum in the left border and a 3% maximum to the right border. Negative values of increase are also acceptable, although I recommend not to use to simplify.

It is very recommended to use always the same number of points among different groups, because the current programming can generate undesiderd distortions (to be corrected soon).

The system allows to define in detail the tension in the extrados and intrados surfaces, but in the air inlets (vents)? The program automatically adds a linear transition in the vents area between extrados and intrados.

The "mysterious" two correction parameters of the last two lines of section 5 continue to have application. Normally no need to modify ever. I recommend use always:
 1000   1.0

There are different ways of defining the skin tension. In the current version it is only active the version of "type 1", which consists of a linear interpolation and a width of reference for applying the law of increments of width, equal to the average width of each panel. Given the large amount of points available to interpolate (100) is not strictly necessary, a version with splines "type 2", to propose later. Usually with 10 or 15 points, linear interpolation is sufficient (old version uses only 6). Another proposal to consider is a version of linear interpolation "type 3" where the law of increments of width is not in reference to the mean width of the panel, but the width existing at each point between two adjacent profiles adjacent (possibly this is the solution that is most perfect).

To clarify and better explain all these fundamental issues, soon I'll be posting an article with diagrams.

Explanation of the parameters in section 31:

Line 1: integer
if integer = 0 then no not use new skin tension module, and finish writting the section.
if integer = 1 then use new skin tension module, and continue writting:

Line 2: integer
integer =
number of skin tension grups (max= number of ribs)

Line 3: character
character
= comment line explaining the group "i" from rib n1 to rib n2, using X points, and type "1".
(for now, only type "1" is possible, and means it uses linear interpolation between points. Add more points to smooth out, if necessary.)

Line 4: integer1 integer2 integer3
integer4 integer5
integer1 = group number
integer2
= initial rib
integer3
= final rib
integer4 =  points for interpolation
integer5
= 1 , type linear of interpolation

Lines 5 to 5-1+ npoints of interpolation: integer real1 real2 real3 real4
integer
= point of interpolation in consucutive order
real1 = Distance in % of length of the extrados panel starting in the leading edge
real2 = Additional width in % of the extrados panel
real3 =
Distance in % of length of the intrados panel starting in the trailing edge
real4 =
Additional width in % of the intrados panel

(Same geometric definition as in
SECTION 5.)

In the following lines. Continue describing groups starting with the line of comments.

Examples:

Example 1 (do not use new skin tension module):

*******************************************************
*       31. NEW SKIN TENSION MODULE
*******************************************************
0


Example 2:

*******************************************************
*       31. NEW SKIN TENSION MODULE
*******************************************************
1
3
* Skin tension group number "1" from rib 1 to 10, 7 points, type "1"
1    1    10    7    1
1    0.         0.5     0.         0.
2    7.5        1.3     10.        1.33
3    15.        2.5     20.        2.5
4    80.        2.5     80.        2.5
5    90.        1.33    90.        1.33
6    95.        0.65    95.        0.9
7    100.       0.0    100.        0.5
* Skin tension group number "2" from rib 11 to 19, 7 points, type "1"
1    11    19    7    1
1    0.        0.5       0.        0.
2    7.5        1.3     10.        1.33
3    15.        2.5     20.        2.5
4    80.        2.5     80.        2.5
5    90.        1.33    90.        1.33
6    95.        0.65    95.        0.9
7    100.       0.0    100.        0.5
* Skin tension group number "3" from rib 20 to 23, 7 points, type "1"
1    20    23    7    1
1    0.         0.5      0.         0.
2    7.5        1.3     10.         1.33
3    15.        2.5     20.         2.5
4    80.        2.5     80.         2.5
5    90.        1.33    90.         1.33
6    95.        0.65    95.         0.9
7    100.      -0.5    100.         0.5
********************************************************


7. RESULTS

INTERPRETATION OF THE LINE LABELS IN FILE lines.txt

In file lines.txt lines will be labeled like this:   [integer]-[letter]-[integer]

Examples: 1A1, 2A1, 2A2, 4A14,..., 1B1, 2F2, ....

First integer indicates "line level" from below to above. Then level "1" is the riser, level "2" main lines, level "3"
following branching above main lines, and so on.

The middle letter indicates:

-
Lines that belong to the riser (or brake) of the same letter A, B, C, D, F (in the case of the lines belonging lower levell of to two or three branches system)
-
Or the final destination row A, B, C, D, F, in upper ramifications of the case of 4 levels or more

The final integer indicates:

- Line order in the same level, counting from center to tips
- Final rib destination number, 
if the line is for the highest level, anchored under sail

This nomenclature may seem strange, but studying the examples is clear and justified. The name of the line indicates in which part of the glider was inserted. Naturally, it is essential to have the sketch lines, with each line label, drawn at the appropriate place. This is a simplification of the nomenclature already provides the file lep-out.txt file for each line.

It is necessary to better explain the content and interpretation lep-out.txt (...).

8. NEXT DEVELOPMENTS

- DXF and STL surfaces, representing a model of the skin tensioned and 3D-shaped surface. Probably will be used to CFD analysis.
- Roman numbers, extend representation control
- Alternatives to roman numbers (decimal)
- Integrate “3D” panel plans in boxes (-1,3),(0,3) and (-1,5) (0,5) to classical panel locations (1,3) (2,3) and (1,5),(2,5) (since version 3.14+)
- Automatically panel colors division.
- DXF parts in blocs (?)
- Use standard .dat files for airfoils?
- Add new vents types 4 and -4, type diagonal fully adjustable
- Set paperspaces and viewports


The Graphical User Interface, It is also evolving, thanks a very big python programming developpment work done by Stefan from Switzerland.
But for now, you need to try to understand my  drawings and cryptic explanations, and write the parameters directly into the text file!


It is very recommended reading and understanding some example files leparagliding.txt included in LE paragliders designs.

FAQ leparagliding.
Download page
Current version of LEparagliding is 3.15 "Canigó"
And pre-processor is 1.6 "Canigó"

Pere Casellas
pere at laboratoridenvol dot com
Teià-Barcelona
January 17, 2021


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