LEPARAGLIDING 3.29 "Jardins"
USER MANUAL

SECTION 2: AIRFOILS

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

• integer : Rib number
• 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 value is "0" or "1", only used in single skin paragliders (useless in double skin). More control in rotation of triangles. Real value "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 %).

Figure 6. Miribs definition in lep < 2.50 (since lep‑2.50 minirib "i" was defined at LEFT, between "i‑1" and "i")

Figure 7. Interpretation 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)

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)

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

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 : Triangle base as % of chord
• real : Triangle height as % of chord
• real : Rotation angle of the base
• real : Radius of the smoothed corners
• real : 0. (not used)
• real : 0. (not used)

Figure 10. Hole type 3 triangle

If the hole is type 4, type in a horizontal line:

• integer : 4
• real : x Distance from LE to main rectangle corner in % of chord
• real : y Distance from chord line to main rectangle corner in % of chord
• real : a rectangle width as % of chord
• real : b rectangle height as % of chord
• real : Rotation angle (degrees) relative to chord line
• real : Radius (%) of the smoothed corners
• real : 0. (not used)
• real : 0. (not used)

The main vertex or reference vertex of the rectangle is the bottom left. If the width value (a) is positive, the rectangle is drawn to the right of the main vertex. If the value of (a) is negative, then the rectangle is drawn to the left. Similar to the case of triangular holes.

Image 10.1 Parameters for hole type 4 (rectangular)

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

A better explanation >

Figure 11: Skin tension

Then add two more lines with the following parameter (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.

Figure 12. Ripstop elasticity

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

The justification for this line is complex. There are two possible 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 an old feature and actually is not recommended. 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:

Figure 13. Sewing corrections

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 that signifies force the program to use maximal precision, reformatting panels to achieve accuracy better than 0.1 mm (lengths differences between 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, approx < 0.01 mm.

The description of the geometrical problem and the solution is described here.

In file lep‑out.txt is a report in section 6, indicating the final lengths of the panel at left, rib, panel at right, and maximal difference and distortions 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 chord
• 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

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
2 = lower branches lined by weighting type 2
3 = lower branches lined by weighting type 3 (spanwise and chordwise optimization). Read more details here.

• 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, i10, i11 — Ramifications and levels

• These are considered the ramifications from the bottom to the top. The main riser is 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 it 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, i10, i11 — Ramifications and levels

... and so on.

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

FIGURE 15: Suspension lines matrix

SECTION 10: BRAKES

• real : brake length
• 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.

Brakes distribution:

• 4 reals : s1, s2, s3, s4, s5 (lengths along vault and from center wing)
• 4 reals : d1, d2, d3, d4, d5 (lengths increments in brake line)

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)

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

Figure 18. Mini‑rib 1 (horizontal strap)

Type 2: Diagonal partial V‑rib centered in rib i

Figure 19. Mini‑rib 2 (V‑rib)

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

Figure 20. Mini‑rib 3 (full V‑rib)

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

Figure 21. Mini‑rib 4 (VH‑rib)

Type 5: full continuous VH‑rib centered in rib i

Figure 22. Full continuous V‑ribs type 5 using parabolic holes (if t<100%)

Figure 23. Full continuous 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, i.e. 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).

Figure 24 V‑rib type 6 general diagonal

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 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:

SECTION 12: H V and VH RIBS (exemple complet)

***************************************************
*   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.

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

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.

... and so on.

• 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.

Figure 25. Extrados colors

*****************************************************
*   15. Extrados colors
*****************************************************
-2
3
2   1
1   40.1   20.15   10.  0.
3   1
1   20.15   0.00   10.  0.
4   3
1       0.0    15.0   10.  0.
2       15.0   30.0   10.  0.
3       50.0   60.0   10.  0.

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 rigidity coefficient of each line, the elongation estimated by Hook's law: F = k·dx

This load distribution is also used when calculating line branches, optimized according to option number 3 (SECTION 9).

• 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 : p, 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

Example:

*****************************************************
*    18. Elastic lines corrections
*****************************************************
100
75   25               <<< A=75% B=25%
40   40   20          <<< A=40% B=40% C=20%
35   35   20   10     <<< A=35% B=35% C=20% D=10%
35   35   15   10   5 <<< A=35% B=35% C=15% D=10% E=5%
1   0.08   0.2   0.2
2   0.08   0.2   0.2
3   0.08   0.2   0.2
4   0.08   0.2   0.2
5   0.08   0.2   0.2

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

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

Line 1: 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

Line 4: text1 text2
text1: line‑sewing (do not change this text)
text2: layer name for sewing lines, to choose freely

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

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

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

Line 9: text1 text2
text1: text (do not change this text)
text2: text layer name, to choose freely.

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

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

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

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

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

Line 2 (typepoint – OK):
text integer real real integer real real
text: typepoint (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 (typepoint2 – not used, set defaults):
text integer real real integer real real
text: typepoint2
integer: 1=unidimensional, 2=minicircle – print
real: radius in mm – print
real: offset in mm – print
integer: 1=unidimensional, 2=minicircle – laser
real: radius in mm – laser
real: offset in mm – laser

Line 4 (typepoint3 – not used, set defaults):
text integer real real integer real real

Line 5 (typevent – OK):
text integer real real integer real real
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 (typetab – OK):
text integer real real integer real real
text: typetab
integer: 1=three orange points, 2=three orange full control, 3=triangle – print
real: points separation or segment in mm – print
real: offset in mm – print
integer: 1=three orange points, 2=three orange full control, 3=triangle – laser
real: points separation or triangle height in mm – laser
real: offset in mm – laser

Line 7 (typejonc – not used, set defaults):
text integer real real integer real real
text: typejonc

Line 8 (typeref – not used, set defaults):
text integer real real integer real real
text: typeref

Line 9 (type8 – OK):
text integer real real integer real real
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 (type9 – OK):
text integer real real integer real real
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 – print and laser
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 (type10 – OK):
text integer real real integer real real
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

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

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)

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

Line 1: integer – if integer = 0 rods are not considered; if integer = 1 add some others parameters to define and draw rods.

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

Line 2: 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 (normally 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 (normally 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
2.0  1.0  3.0  2.5
3.0  2.0  4.0  2.0
2.0  5.0  3.0  2.0
2    16   19
2.0  1.0  3.0  2.5
3.0  2.0  4.0  2.0
2.0  5.0  3.0  2.0

Note: The parameters for type 2 rods (arched rods) are defined similarly but with a different structure. See the full manual for details.

SECTION 21: JONCS DEFINITION (NYLON RODS) – continuació

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

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, 2, or 3.

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 three lines that define the geometry of the 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...

If integer2 in line3 was 3, means use two rods per nose (upper and lower) for use in "shark nose" airfoils. Then write consecutively the following lines:

Line 4: integer – number of groups to define.

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 (same as rod type 1)
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 (normally use n=2.0, parabolic)

Line 7: real1 real2 real3 real4 (same as rod type 1)
real1: bottom part of upper rod init point deflection in % of chord
real2: parabolic deflection length in % of chord
real3: value of max deflection in % of chord
real4: value n of exponent in curve of deflection type y=k·x^n (normally use n=2.0, parabolic)

Line 8: real1 real2 real3 real4 (same as rod type 1)
real1: upper part of lower rod init point deflection in % of chord
real2: parabolic deflection length in % of chord
real3: value of max deflection in % of chord
real4: value n of exponent in curve of deflection type y=k·x^n (normally use n=2.0, parabolic)

Line 9: real1 real2 real3 real4 (same as rod type 1)
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 (normally use n=2.0, parabolic)

Line 10: real1 real2 real3 real4 (same as rod type 1)
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)

(continue same structure with next group if defined...)

View parameters interpretation:

• xeini: extrados deflection initial point %
• xefin: extrados deflection final point %
• ye: extrados deflection %
• ne: extrados exponent parabolic deflection
• xsne: extrados rod (lower part) init of deflection %
• ae: deflection length %
• be: deflection %
• nsne: parabolic exponent
• xsni: intrados rod (upper part) init of deflection %
• ai: deflection length %
• bi: deflection %
• nsni: parabolic exponent
• xiini: intrados deflection initial point %
• xifin: intrados deflection final point %
• yi: intrados deflection length %
• ni: intrados exponent parabolic deflection
• s1: offset (mm) defining the rod (see figure rod type "1")
• s2: external width of pocket (mm)
• s3: width for rod between sewing lines (mm)
• s4: internal width of pocket (mm)

Figure 27c. Rods type 3 definition (shark nose)

Image double rod type 3 (shark nose)

If integer2 in line3 was 4, means use long extrados joncs. Then write consecutively the following lines:

Line 4: integer – number of groups to define.

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
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 (normally use n=2.0, parabolic)

Line 7: 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 (normally use n=2.0, parabolic)

(continue same structure with next group if defined...)

If integer2 in line3 was 5, means use long intrados joncs. Then write consecutively the following lines:

Line 4: integer – number of groups to define.

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
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 (normally use n=2.0, parabolic)

Line 7: 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 (normally use n=2.0, parabolic)

(continue same structure with next group if defined...)

Rods type 1 (nose), type 4 (extrados), and type 5 (intrados)

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

Example 3: Commented scheme "2". Using only one data bloc type 2 and two groups. 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: Commented 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

Example 5: Scheme "2" using one data bloc, first data bloc type 3 "shark nose", one group from rib 1 to 30.

*******************************************************
*    21. JONCS DEFINITION (NYLON RODS)
*******************************************************
2                      < scheme 2
1                      < one bloc
1 3                    < first bloc type 3 "shark nose"
1                      < one group
1 1 30                 < first group from rib 1 to 30
4.2   10.8    1.0   2.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
3.5   5.0     1.0   0.7  < upper rod initial point % of parabolic modification, length, deflection, exponent
4.5   5.0     2.2   1.0  < upper rod initial point % of parabolic modification, length, deflection, exponent
3.67  12.1    0.79  2.0  < coordinates (x1,y1) (x2,y2) and deflection all in % of chord
0.0   10.35   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!

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

Example 6: using rods type 1, 2, 4:

*******************************************************
*    21. JONCS DEFINITION (NYLON RODS)
*******************************************************
2                > Scheme 3
3                > Use 3 blocks
1 1              > Block 1 type 1
1
1 1 25
12.0  18.5     1.5   2.0
7.0   15.0     2.0   2.0
0.0    9.35    6.3   9.35
2 4              > Block 2 type 4
1
1 1 25
23.5  29.5   1.1   2.0
63.0  70.0   1.1   2.0
0.0    9.35  6.3   9.35
3 5              > Block 3 type 5
1
1 1 25
23.5  29.5   1.1   2.0
63.0  70.0   1.1   2.0
0.0    9.35  6.3   9.35

SECTION 22: NOSE MYLARS DEFINITION

Line 1: integer
if integer = 0 mylars are not considered
if integer = 1 add some others parameters 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.

Figure 28. Section 22 nose mylars definition

SECTION 23: TAB REINFORCEMENTS

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

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

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
text1: 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
text1: 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
text1: 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
text1: 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
text1: 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
text1: 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

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

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

Line 10: text1 integer integer text2
text1: Intrados (do not change this text)
integer: if set to "0" unifilar intrados is not drawn, if set to "1" is drawn
integer: color index for the intrados
text2: 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 us to define different types of air inlets (vents), and automatically "glue" into the panel of extrados, intrados, or to separate them. The vents include sewing edges. The skin tension in the vent is linear and automatically corresponds to that defined at the points corresponding in extrados and intrados.

The vent definition is very easy and intuitive. A row is defined for each rib. The first number is the rib number, the next is the vent type, and then zero, two, or three parameters, depending on the type.

Available vent types (version lep‑3.17) 0,1,-1,-2,-3,4,-4,5,-5,6,-6:

• 0 means do not glue anywhere (open air inlet).
• 1 means glue the vent to the extrados (normally used in paragliders single skin type).
• -1 means glue the vent to the intrados (usually means, closed cell).
• -2 means diagonal vent 100% open at left, glued to intrados.
• -3 means diagonal vent 100% open at right, glued to intrados.
• -4 50 30 mean general diagonal vent 50% closed at left and 30% closed at right, glued to intrados.
• 4 0 80 mean general diagonal vent 0% open at left and 80% open at right, glued to extrados.
• 5 50 100 10 mean arched vent, 50% open at left, 100% open at right, and 10% arc depth, glued to intrados.
• -5 50 40 15 mean arched vent, 50% closed at left, 40% closed at right, and 15% arc depth, glued to intrados.
• 6 80 80 means elliptical inlet, width of 80% in X direction and 80% in Y direction, glued to extrados.
• -6 50 85 means elliptical inlet, width of 50% in X direction and 85% in Y direction, glued to intrados.

Section 26 structure:

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 real1 real2 real3
integer1: airfoil number (cell between airfoil i and airfoil i‑1)
integer2: vent parameter (available parameters 0, 1, -1, -2, -3, 4, -4, 5, -5, 6, -6 as explained above)
real1: parameter 1 (0 to 100). Start point at left (vents 4, -4, 5, -5), or horizontal axis in 6, -6
real2: parameter 2 (0 to 100). Start point at right (vents 4, -4, 5, -5), or vertical axis in 6, -6
real3: parameter 3 (0 to 100). Arch depth in vents type 5 or -5

Example 1 (use old style, not recommended):

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

Example 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

Example 3 (advanced vents):

*******************************************************
*    26. GLUE VENTS
*******************************************************
1
1    0
2    0
3    1
4   -4 100. 0.   ---> general diagonal vent from 100% to 0%
5   -4 10. 50.   ---> general diagonal vent from 10% to 50%
...
19  -5 0. 0. 15  ---> arc vent 15% depth
20  -6 80 80     ---> elliptical inlet
21  -1
22  -1
23  -1

Figure 30. Glue vents

Figure 31: Vents types 0,1,-1,-2,-3

Figure 31b: Vents types -4,4 (general diagonal) -5,5 (general arc) -6,6 (elliptical inlet), available in lep‑3.17 and later. Note that type 4 also includes cases 0,1,2,3, and type -4 cases 0, -1, -2, -3. Finally type 5 includes case 4, and -5 includes case -4.

SECTION 27: SPECIAL WINGTIPS

It is used for defining wingtips with special shapes. Available values 0, 1, 2.

Wingtip type "1":

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 45° for example. "AngleTE" is a name not computed for the trailing edge. Set the angle as desired, -7.78° for example.

Example 2:

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

Wingtip type "2":

In 3.27+ version, I have started working on the rounded wingtip with a parabola, but only draw in planform, not redesign the panels yet :( Read more: https://laboratoridenvol.com/leparagliding/dev/lep-dev.en.html

Example, special wingtip type 2:

*******************************************************
*    27. SPECIAL WING TIP
*******************************************************
2
AngleLE 45
AngleTE -7.78

SECTION 27: SPECIAL WINGTIPS – continuació

Example, special wingtip type 2 (rounded wingtip with parabola):

*******************************************************
*    27. SPECIAL WING TIP
*******************************************************
2
Distance  60.
Angle     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.

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 pitch 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:

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 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 – 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 -4° and compute in 4 steps
• Trim angle set to 5° and compute in 10 steps

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

SECTION 29: 3D SHAPING

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 of 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 applied 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 do not use 3D-shaping, and finish writing the section.
if integer = 1 then use 3D-shaping, and continue writing.

Line 2: 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
integer = 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, ...

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
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, ...

(...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 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 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 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 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 indicates to draw with symmetry, 1 only one side.

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 writing. 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, than 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 cut 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

Example 5: Enabling the external DXF and STL files.

************************************************************
*    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 1    1    15   1    > Enable 3D tessellation in lep-3d.dxf from panel 1 to 15 and do symmetrical
exteDXF 1    1    15   0    > Enable 3D tessellation in independent file lep-3d-surfaces.dxf from panel 1 to 15 and do one side
exteSTL 1    1    15   1    > Enable 3D tessellation in independent files lep-3d-surfaces.scad and lep-3d-surfaces.stl from panel 1 to 15 and do symmetrical

lep-3d.dxf with tessellation active. line colors, defined according to section 25	lep-3d-surfaces.dxf external dxf file showing only one cell
One panel in OpenSCAD	One panel in OpenSCAD (rendered)
Full wing model in OpenSCAD, file lep-3d-surfaces.scad automatically generated	lep-3d-surfaces.scad
lep-3d-surfaces.scad	lep-3d-surfaces.scad
Automatically generated file lep-3d-surfaces.stl View and renders in OpenSCAD STL file can probably be used in CFD analysis	Automatically generated file lep-3d-surfaces.stl View and renders in FreeCAD

Some limitations of 3D surfaces:

• The scad model allows us to view the entire wing without problems (key [F5]), but does not allow rendering (key [F6]) I'm trying to find out why.
• The 3D surfaces accurately represent the law of skin tensions, but currently do not take into account 3D shaping. Perhaps later, I try to represent this effect.
• The number of points in the tessellation is equal to the number of points in the profile around its outline, and a fixed number of segments in the transverse direction. The parameter nsegments=8 has been defined internally. If you need a finer mesh, change this setting (compile the program or ask me).

General notes:

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 (ballooned) 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 nose 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
Integer: 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 ovalization. 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 undesired 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 do not use new skin tension module, and finish writing the section.
if integer = 1 then use new skin tension module, and continue writing.

Line 2: integer – number of skin tension groups (max = number of ribs).

Line 3: 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 consecutive 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.

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

SECTION 32: PARAMETERS FOR PARTS SEPARATION

The program separates the different pieces (panels, ribs, ...) drawn in 2D automatically, trying to not overlap with each other or put outside the drawing box. However, sometimes the separation between the pieces is not as we would like. Therefore, we have added some parameters to modify the automatic separation criteria. These are coefficients, around 1.0 that reduce or increase the separations in horizontal (x) or vertical (y) directions. If in doubt, do not need to change any of the parameters in this section, leave the default values to 1.0, or put a single parameter 0 at the beginning, which is equivalent to maintaining the default default values. And so it will be an invariant section for all models.

Example 1:

*******************************************************
*    32. PARAMETERS FOR PARTS SEPARATION
*******************************************************
0

Example 2:

*******************************************************
*    32. PARAMETERS FOR PARTS SEPARATION
*******************************************************
1
1.2
0.8

SECTION 32: PARAMETERS FOR PARTS SEPARATION – continuació

Example 2:

*******************************************************
*    32. PARAMETERS FOR PARTS SEPARATION
******************************************************
1
panel_x      1.2
panel_x_min  1.0
panel_y      0.8
rib_x        0.8
rib_y        1.0
rib_1y       1.8
jonc_x       0.8
jonc_y       1.0
jonc_i       0.25
parameter10  1.0

Explanation of the parameters in section 32:

Line 1: integer
if integer = 0 then use default internal parameters, and finish writing the section.
if integer = 1 then use control parameters, and continue writing ten lines.

Line 2: character real
character = parameter 1 name
real = multiplication factor for x‑direction panels separation.

Line 3: character real
character = parameter 2 name
real = multiplication factor for x‑direction panels minimum separation.

Line 4: character real
character = parameter 3 name
real = multiplication factor for y‑direction panels separation.

Line 5: character real
character = parameter 4 name
real = multiplication factor for x‑direction ribs separation.

Line 6: character real
character = parameter 5 name
real = multiplication factor for y‑direction ribs separation.

Line 7: character real
character = parameter 6 name
real = multiplication factor for adjust separation in y‑direction the horizontal straps type 1 or 11.

Line 8: character real
character = parameter 7 name
real = multiplication factor for adjust separation in x‑direction the rod pockets in box(1,7).

Line 9: character real
character = parameter 8 name
real = multiplication factor for adjust separation in y‑direction the rod pockets in box(1,7).

Line 10: character real
character = parameter 9 name
real = multiplication factor for adjust separation in y‑direction the lower rod pocket in case shark nose rods (type 3).

Line 11: character real
character = parameter 10 name
real = 1.0 (parameter still not used).

To better understand, initially set all parameters to 1.0 and then make changes to see the results.

Figure 37. Section 32 example. The panels above have been drawn with a compact configuration (panel_x = 1.0, panel_y = 0.3). The panels below have been drawn with a more separate configuration (panel_x = 1.2, panel_y = 1.2).

SECTION 33: DETAILED RISERS

Type a single parameter "0" to bypass this section and use pre‑set values :)

Example 1 (bypass):

*******************************************************
*    33. DETAILED RISERS
*******************************************************
0

Type 1 and additional parameters to design a paraglider with risers of different lengths A, B, C, D, E (not usual, but sometimes it may be necessary). Works. Type 2, 3 or 4 to project the risers of a vario seat system of two, three, four points (types 2,3,4 still not available).

Example 2 (type 1):

*******************************************************
*    33. DETAILED RISERS
*******************************************************
1
1
A   45.0 cm
B   50.0 cm
C   60.0 cm

Explanation of the parameters in section 33:

Line 1: integer
if integer = 0 then use default internal parameters, and finish writing the section.
if integer = 1 then use control parameters, and continue writing.

Line 2: integer – risers type (1 = risers of defined length, 2 = vario seat two points, 3 = vario seat three points, 4 = vario seat four points).

And then write N lines, being N = number of risers according definition in section.

Lines 3 to 3+N‑1: character1 real character2
character = write A, B, C, D, E... according riser definition in SECTION 8 (nrisers = plans number)
real = riser length in cm
character = cm.

SECTION 34: LINES CHARACTERISTICS TABLE

Type a single parameter "0" to bypass this section and use predefined typical values. Definition table of the properties of N different types of lines used in our paraglider. Up to 50 different types of lines. Define your own lines types according to manufacturers' tables.

Example:

*******************************************************
*    34. LINES CHARACTERISTICS TABLE
*******************************************************
1
6
1 r  25.  2. Riser    1000 daN  polyester   20.0   g   s 12. cm  7
2 c  1.90    Line275    275 daN  s_dyneem    2.26   g   s 12. cm
3 c  1.40    Line160    160 daN  s_dyneem    1.34   g   s 10. cm  3
4 c  1.15    Line120    120 daN  s_dyneem    1.00   g   s 10. cm  5
5 c  0.80    Line100U   100 daN  u_dyneem    0.43   g   p 8.   cm  2
6 c  2.00    Line200B   200 daN  s_dynemm    3.10   g   s 12. cm  6

Each type is described in a line with 12 positions:

• 1 → Line type
• 2 → r or c (r=rectangular axb or c=circular section)
• 3 → line diameter (mm) or a dimensions (mm)
• 3.5 → nothing or b dimension (mm), used only in "r" types
• 4 → line label "Riser", "PPSL275", "DC60",... use names without spaces up to 15 characters
• 5 → minimum breaking strength (daN)
• 6 → daN
• 7 → material type "dyneema", "aramid", "polyester"... use names without spaces up to 15 characters
• 8 → weight per line meter (g)
• 9 → g
• 10 → s or p (s=stitched or p=spliced loop)
• 11 → total loop length (cm)
• 12 → cm
• 13 → set line CAD color, used only if code 1341 is active in section 37 (idea by Eric Fontaine)

SECTION 35: SOLVE EQUILIBRIUM EQUATIONS

Read full report here about improvements added since version 3.20V (pdf).

Type a single parameter "0" to bypass this complicated section! :)

*******************************************************
*    35. SOLVE EQUILIBRIUM EQUATIONS
*******************************************************
0

Section 35 sets the initial basic parameters used to solve the longitudinal equilibrium of the paraglider. This section is informative and is used by the designer, to study the values of the forces involved in the balance of the wing, the flight speed, the angles, and the glide coefficient.

To find realistic values, it is necessary to do the study simultaneously with the XFLR5 program or CFD programs, and perform several iterations until satisfactory values are obtained. Currently, it is not yet possible to fully automate this calculation. The designer must apply his criteria according to the type of wing under study.

We have discussed this section extensively with Francois de Villiers during the last few weeks, using different approaches to the final solution.

Example with parameters:

*******************************************************
*    35. SOLVE EQUILIBRIUM EQUATIONS
*******************************************************
1
g       9.807  m/s2 gravity of Earth
ro      1.225  kg/m3 air mass density
mu      18.46  muPa·s air dynamic viscosity (microPascals)
V       12.7   m/s  estimated flow speed
Alpha   9.45   deg  estimated wing angle of attack at trim speed
Cl      0.55619     wing lift coefficient
cle     1.0         lift correction coefficient
Cd      0.03560     wing drag coefficient
cde     1.35        drag correction coefficient
Cm      0.0         wing moment coefficient
Spilot  0.438  m2   pilot+harness frontal surface
Cdpilot 0.6         pilot+harness drag coefficient
Mw      5.0    kg   wing mass
Mp      65.9   kg   pilot mass included harness and instruments
Pmc     0.2    m    pilot mass center below main carabiners
Mql     8.0    g    one quick link mass (riser‑lines)
Ycp     0.489  m    y‑coordinate center of pressure
Zcp     0.299  m    z‑coordinate center of pressure

Explanations:

• g → gravity of Earth (9.80665 m/s2 standard gravity)
• ro → air mass density kg/m3
• mu → air dynamic viscosity microPascal·s
• V → estimated initial flow speed m/s, used for first Cl, Cd, Cm values
• Alpha → estimated ideal angle of attack deg. Max glide ratio according wing aerodynamic analysis
• Cl → Wing lift coefficient, obtained by analysis with individual profiles, XFLR5, or CFD
• Cle → multiplier coefficient of Cl, to consider non‑modeled geometries, use 1.0 in case of doubt
• Cd → Wing drag coefficient, obtained by analysis with individual profiles, XFLR5, or CFD
• Cde → multiplier coefficient of Cd, to consider non‑modeled geometries, use 1.15 in case of doubt. If the Cd data comes from CFD this coefficient can be very close to 1.0. Currently studying how this coefficient affects the results. Probably by adjusting through Cde the expected GR, the rest of the parameters will be very close to reality.
• Cm → Wing moment coefficient, obtained by analysis with individual profiles XFLR5, or CFD
• Spilot → Pilot + harness frontal surface (m2)
• Cdpilot → Pilot+harness drag coefficient (depends on the type of harness, especially if have fairings)
• Mw → Wing mass (kg) without lines and risers
• Mp → Pilot+harness+instruments mass (kg)
• Pmc → Pilot+harness mass center distance from main carabiners (m)
• Mql → Mass of one quicklink used to connect riser with lines (kg)
• Ycp → Y‑coordinate of center of pressure (m), obtained by analysis with individual profiles, XFLR5, or CFD
• Zcp → Z‑coordinate of center of pressure (m), obtained by analysis with individual profiles, XFLR5, or CFD

Remember that the axes used in LEparagliding are:

• Origin (0,0,0) at the nose of the central profile section.
• X‑axis horizontal and in the span direction.
• Y‑axis along the central chord.
• Z‑axis perpendicular to the XY plane and pointing down (not coincides with gravity axis).

SECTION 36: CREATE FILES FOR XFLR5 ANALYSIS

0 → don't perform xflr5 analysis
1 → set parameters for xflr5

*******************************************************
*    36. CREATE FILES FOR XFLR5 ANALYSIS
*******************************************************
1
* Panel parameters
10   chord nr
5    per cell
1    cosine distribution along chord
1    uniform along span
*
* Include billowed airfoils (more accuracy) [Still not working]
0

If you use this section, it will automatically be created in xflr5/ directory with a .xwimp file and profiles in .dat format to use in an aerodynamic analysis with the XFLR5 program. The details of how to do it are explained here: http://www.laboratoridenvol.com/info/lep2xflr5/lep2xflr5.html

Unfortunately with XFLR5 we cannot model paragliders with profile rotations in the Z angle, nor single skin paragliders. CFD programs must be used for this type of paraglider.

Type a single parameter "0" to bypass this complicated section!

SECTION 37: SOME SPECIAL PARAMETERS

This section will be a "wildcard", to add special parameters to control things from previous or future data sections… It is an unorthodox and somewhat "dangerous" section, because any parameter or modification of previous or future ones could be added here. (!).

It will consist of an initial control parameter "0" to end and define nothing! :) Or the parameter "1" to activate the section, and below the parameter N which means add N lines with special parameters.

Each line will start with a control code, an integer that will have a meaning to be specified. And then, on the same line, one or more parameters (integers, reals, or characters) related to the subject of the control code.

It may seem a little abstract..., but you will see that it will be very practical...

For example, it can be used to activate transitions in the thickness of miniribs (HEGALA style...), or add nylons in the middle of the inlets...

The codes available are:

• Code 1146, which means that it is necessary add a real estimated mass center % of a typical section (0% leading edge, 100% trailing edge). Used only to calculate the estimated wing center of mass. Default value is 36%.
• Code 1291, which means that it is necessary to write on the right an integer number which is the number of transversal segments to use on the STL surfaces (related to section 29).
• Code 1341, if code is followed by a "1", then the lines will be drawn according to the colors by type defined in section 34. If it is a "0" the colors will be drawn according to the risers, in accordance with sections 24 and 25. If code 1341 does not exist, the colors are defined by sections 24 and 25.
• Code 1351, set the solve method of equilibrium equations. Six different methods are currently being calibrated. Use only parameter (method 1 or 6). Method 1 used by default.
• Code 1352, set 1 to use flat area, or 2 to use projected area, in Lift, Drag, and speed calculus. Due to the internal adjustments made, this aspect has almost no influence on the results. By default the value used is 2. Use value 2 when using method 4 in code 1352. It is a code that the regular user does not need to specify.
• Code 1353, set 0 to output the standard report in section 17 of lep‑out.txt, or set to 1 or 2 for more detailed output used for studies and calibrating methods. Default is 0. Most verbose mode is 2.
• Code 2000. The optional parameter "2000" which means, then add a date in text format, for example 2026‑01‑28 or "December 28, 2026", which serves to remember the date the project was last saved. If the optional code 2000 is present, the date is printed in the leparagliding.txt and lep‑out.txt files.
• Code 2003, force the assiette angle and use it for calculus of "phi" and "chi" in lep‑out.txt section 12.
• Code 2005, Code "2005" set to 1 or 0. By default is 0 and it means not drawing the blue lines that mark the positions of the miniribs on the upper and lower panels used for laser cutting. Already set to 0 by default in version 3.28. Optionally, we can set it back to 1, in the design phase. In the final phase, it is better to eliminate code 2005 or set it to 0 as it saves the work of manually erasing them. Only the reference points remain.
• Code 2006, Code "2006" set to 1 or 0. By default is 0. Setting it to 0 means not drawing the red and cyan lines drawn at airfoils when using vh‑ribs types 6/16. This saves the work of manually erasing them. Only the reference points remain.
• Code 3001, It serves to add a thickness transition to the miniribs, that is, to progressively and smoothly adapt the thickness of the minirib to that of the ovalized profile (non‑existent) in the central area of each panel.
• Code 3002, In lep‑3.28 previous versions, elliptical holes in profiles were defined by default with 39 segments. Now they are defined by default with 60 segments, for a more precise shape. Additionally and optionally, there is now a parameter available to specify how many segments the ellipses should have. Simply, in section 37 add the new code 3002 and then the number of segments we want.

Example 1 (code 3002):

*******************************************************
*    37. SOME SPECIAL PARAMETERS
*******************************************************
1
1
3002   150              < use 150 segments for ellipses

Example 2 (multiple codes):

*******************************************************
*    37. SOME SPECIAL PARAMETERS
*******************************************************
1
3
2000   "2026-05-02"     < add small note in the dxf with drawing date
3001   3   6.0  1.0     < use minirib transitions type 3
3002   110              < use 110 segments for ellipses

Code 3001 parameters format: integer1 integer2 real1 real2
integer1: 3001 (special code)
integer2: can take the values 0,1,2, or 3; 0 means not to make any transition, the result is the same as not activating code 3001; 1 means to make a linear transition in a distance "S" with a maximum thickness variation "t" up to zero, according to the attached drawing; 2 means to make a double parabolic transition (case not yet available); 3 means to make a smooth transition with a cosine type function, I recommend always using this case.
real1: It indicates the length of the transition in % of the length of the profile chord. It is the parameter "s" in the figure below.
real2: It indicates the amplification coefficient on the thickness "t" calculated automatically by the program. "t" is the difference in thickness between the ovalized profile and the minirib profile. Normally we will use the value 1.0. If we use 0.0 it is equivalent to not making any type of transition.

Figure 38. Minirib transitions

Code 3002 examples (ellipse segments):

Using 4‑segments "ellipses" :-)

Using 9‑segments ellipses "potato" shape :-(

99‑segment ellipses, the precision is already very good, however we can try with 200 or 300 segments without problem. Finally, we must remember the instruction "_pedit" in Autocad (or equivalent program) to join all the segments in a polyline.

Code 2005 and 2006 examples:

Code 2005: blue lines marking minirib positions (set to 1 in design phase).

Setting "2006 0" only reference points remain. Put to 1 only in design phase.

Setting "2006 0" only reference points remain (detail). Set by default in version lep‑3.29.

Full example including codes 2000, 3001, 3002 added in lep‑3.28:

*******************************************************
*    37. SOME SPECIAL PARAMETERS
*******************************************************
1
7
1291    12   nsegments in transverse direction (stl surfaces)
1341     1   use CAD colors for each line type according table 34
1146    36.  gravity center in % of a typical section (default is 36%)
1351     1   Solve method (1 or 6), default is 1
1352     2   Use flat area (1) or projected area (2), default is 2
1353     2   Print normal (0) or advanced detailed output (1),(2)
2003   -1.1
3001     3   6.0  1.0  use minirib transitions

Another full example:

*******************************************************
*    37. SOME SPECIAL PARAMETERS
*******************************************************
1
6
1341   1    use CAD colors for each line type according table 34
2000   "2026-08-18"  edition date
3001   3   6.0  0.85  use cosinuidal mini-rib transitions
2005   1
2006   1
3002   55   ellipse segments

Type a single parameter "0" to bypass this section! :)

*******************************************************
*    37. SOME SPECIAL PARAMETERS
*******************************************************
0

SECTION 38: HVR HOLES

This section will be greatly appreciated by "friends of holes" in internal parts. It is now possible to add holes very easily to type 5/15 vribs (complete diagonal ribs), to type 6/16 vribs (diagonals or universal bands located anywhere on the wing), and to type 9 which we will call airfoil miniribs. Taking advantage of the same data structure, we will soon be able to add more types and varieties of holes. However, it must be remembered that this section is "not necessary" and the same or better can be done by completing the drawing with CAD. But automation saves a lot of time and improves accuracy.

The structure of section 38 is as follows:

Section header with three lines exactly like these:

*******************************************************
*    38. HVR HOLES
*******************************************************

Line 4 is an integer that if equal to 0 means to end the section and not consider additional holes. If equal to 1 means to continue adding more data.

Line 5 is an integer indicating the number of lines to read next.

Lines 6 and following have the following structure of 9 fields:

integer1 integer2 integer3 integer4 real1 real2 real3 real4 real5

• integer1 : line number
• integer2 : vrib type (9, 15 or 16)
• integer3 : 0 means no holes drawn, 1 means drawn type‑1 distribution
• integer4 : holes number

If integer2 is 16:

• real1 : %hole height compared to local height of the vrib (0. to 100.)
• real2 : %hole width compared to local height of the vrib (0. to 100.)
• real3 : hole (ellipse) center position factor with respect to height vrib (0. to 1.0)
• real4 : not used
• real5 : not used

If integer2 is 15:

• real1 : %hole height compared to local height of the vrib (0. to 100.)
• real2 : %hole width compared to local height of the vrib (0. to 100.)
• real3 : hole (ellipse) center position factor with respect to local height vrib (0. to 1.0)
• real4 : not used
• real5 : not used

If integer2 is 9:

• real1 : %hole height compared to total local height of the minirib (0. to 100.)
• real2 : %hole width compared to total height of the vrib (0. to 100.)
• real3 : ellipse excentricity a/b (0. to 1.0)
• real4 : displacement of the ellipse center respect to the profile chord (-1.0 to 1.0)
• real5 : not used

Holes in type 6/16 (universal diagonals)

Holes in type 5/15 (full diagonal ribs)

Holes in type 9 (miniribs)

Examples:

Minimal:

***************************************************
*    38. HVR HOLES
***************************************************
0

Complete example:

***************************************************
*    38. HVR HOLES
***************************************************
1
3
1   16  1   5   70.  50.  0.5  0.0  0.0
2   15  1   3   45.  25.  0.6  0.0  0.0
3    9  1   4   70   0.6  -0.15 0.0  0.0

SECTION 39: HVR POSITION PARAMETERS

This section is a "non‑important" type (it has no effect on the wing design), which can be used to improve the position of the vhribs parts in the DXF drawing by adjusting their horizontal and vertical separation with some coefficients, when the default parameters cause the parts to not be well positioned in the corresponding drawing box.

It completes and expands the parameters defined in section 32 which is of the same "non‑important" type.

The structure of section 39 is as follows:

Section header with three lines exactly like these:

***************************************************
*    39. HVR POSITION PARAMETERS
***************************************************

Line 4 is an integer that if equal to 0 means to end the section and not consider additional parameters. If equal to 1 means to continue adding more data.

Line 5 is an integer indicating the number of lines to read next, in this version it should be 6.

Lines 6 and following have the following structure of 3 fields:

character real1 real2

• character : vrib reference name, do not change
• real1 : factor to adjust horizontal separation, typical values between 0.0 1.0 or higher
• real2 : factor to adjust vertical separation, typical values between 0.0 1.0 or higher

Types 2,3,4 still not active.

Minimal example:

***************************************************
*    39. HVR POSITION PARAMETERS
***************************************************
0

Complete example:

***************************************************
*    39. HVR POSITION PARAMETERS
***************************************************
1
6
vrib_type1   0.5  1.0
vrib_type2   1.0  1.0
vrib_type3   1.0  1.0
vrib_type4   1.0  1.0
vrib_type5   0.4  1.0
vrib_type6   0.4  1.0

7. RESULTS

DXF Files

TXT Files

STL Files

SCAD Files

(to explain...)

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 level 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.

Note: It is necessary to better explain the content and interpretation of all output files (...).

8. NEXT DEVELOPMENTS

• Automatically panel colors division.
• DXF intensive use of polylines instead of individual segments
• DXF parts in blocs (?)
• Use standard .dat files for airfoils?
• Show miniribs in 3D model
• Miniribs smooth tessellation in 3D (DXF/STL)
• Alternatives to roman numbers (decimal)
• Intermediate nose rods (without rib)
• Increase max lines levels from 4 to 5
• Increase max anchors number from 5 to 30
• Set paperspaces and viewports by default
• Add some improved .odt or .html output report
• Update pre-processor version
• Pre-processor html interface
• Full html interface (in development...)
• Reduce total code size and increase speed of calculus improving internal subroutines and variables names

The Graphical User Interface is also evolving, thanks to a very big python programming development work done by Stefan Feuz 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 3.29 "Jardins"
And pre‑processor is 1.6 "Canigó"

Pere Casellas
pere at laboratoridenvol dot com
Vinebre, Catalonia
August 23, 2026

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