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LEPARAGLIDING 2.0
USER MANUAL
1.
INTRODUCTION
2.
GENERAL CONCEPTS
3.
FILES ASSOCIATED WITH THE PROGRAM
4.
HOW TO WORK WITH THE PROGRAM
5.
COMPOSITION OF THE AIRFOIL FILE
6.
COMPOSITION OF THE INPUT DATA FILE leparagliding.txt
SECTION
1: GEOMETRY
SECTION
2: AIRFOILS
SECTION
3 : ANCHOR POINTS
SECTION
4: LIGHTENING IN THE RIBS (RIB HOLES)
SECTION
5: SKIN TENSION
SECTION
6: SEWING
ALLOWANCE
SECTION
7: SEWING
MARCAGE
SECTION
8: ESTIMATING THE GENERAL ANGLE OF ATTACK
SECTION
9: DESCRIPTION OF LINES
SECTION
10: BRAKES
SECTION 11: RAMIFICATIONS LENGTH
SECTION 12: H V and
VH RIBS
SECTION 15: EXTRADOS
COLORS
SECTION 16: INTRADOS
COLORS
SECTION 17: ADITIONAL
RIB POINTS
SECTION 18: ELASTIC
LINES CORRECTION
7.
FUTURE DEVELOPMENTS
FIGURE
INDEX
1. INTRODUCTION
This manual
describes the use of the "leparagliding 2.0" created by Laboratori
d'envol for the design of paragliders. The author of the program
provides no other information as described in the web. There is no
warranty for the correct operation of the program. You assume the full
consequences of use of the program.
LEparagliding is very "cryptic" to use, but very powerfull...!
Please, forgive my writings in English, not good enough, beacuse is not
my usual language!
2. GENERAL CONCEPTS
LEparagliding is
a calculation engine written in g77 FORTRAN language, that performs the
reading of the data input files, and writes the results to the output
files.
Input
files:
leparagliding.txt
Contains
detailed geometric definition of the entire paraglider. The designer
must edit this text file to achieve the desired results.
airfoil1.txt
airfoil2.txt
...
They contains
coordinate files of the profiles, taking a unit chord. Can be assigned
a specific profile name of each rib. However the most common is a
general airfoil
aplied to tthe entire wing and a zero thickness airfoil for the last
profile of the wingtip,
Output files:
leparagliding.dxf
Contains
drawings in DXF format to be visualized. analyzed and edited with a CAD
program (Autocad, Microstation ...)
lep-3d.dxf
Dxf file created
automatically by the program and contains 3D model.
lep-out.txt
Text
output file with the main parameters calculated on the wing (span,
area, aspect ratio, finenesse, ...) and the ordered list of the lengths
of
all lines in the wing (main line plans and brakes).
3.
FILES ASSOCIATED WITH THE PROGRAM
leparagliding.f
File program
source code, written in language "GNU Fortran 77". This file is not
necessary for the end user. Is included for developers who want to make
modifications, improvements and extensions to the code, or for
students. These
changes are completely free under the principles and conditions of the
GNU General Public License 2.0 (http://www.gnu.org) which is
distributed the program.
The
author of the file leparagliding.f program keeps it evolving and
improving, as are several important aspects to implement and enlarge
the use and possibilities of the program. Adjustments are also made to
particular designs.
leparagliding.txt
Text file that
contains the main geometric definition of the glider model, whose
detailed description is made below.
gnulab2.txt, airplan.txt
Text files
containing the coordinates of the profile used. There may be many files
you want to profile (possible apply a different profile in each rib,
although that is not common)
a.out
(Linux) or a.exe (Windows)
Executable
program that must be activated to read the data and obtain graphical
and numerical results.
leparagliding.dxf
Dxf
file created automatically by the program and contains all drawings of
the
wing panels with patterns ready to print or further postprocess in a
CAD
program.
lep-3d.dxf
Dxf file created
automatically by the program and contains 3d model.
lep-out.txt
Text file with
the numerical results of the program.
4.
HOW TO WORK WITH THE PROGRAM
Working with
LEparagliding consists of the following phases:
1.
Pre-process
It
is the initial phase of design, whether CAD or pencil and graph paper
and calculator. It defines the shape in plan, the lobe or vault and the
desired inclination of the ribs. Note
that the pre-process work with paper, pencil, calculator and definition
of discrete
analytic functions, enables the same precision as with CAD.
An
analytical pre-processor is under preparation.
2.
Edit data file
Descibed below in detail. Complete sections 1 to 18.
It is the most important
operation, and the overall design
of the glider
itself
3.
Program execution (seconds)
GNU/Linux:
run ./a.out in a
terminal
Windows: execute a.exe
including cygwin1.dll in the same directory.
Mac OSX: compile sorce code in a terminal: " f77 leparagliding.f" and
run "./a.out" in terminal as in linux
(compiler name will be f77 g77 or equivalent). Not tested
yet.
4.
Viewing the drawings (CAD)
The
program CAD displays the results dxf file. Please use 'zoom_extension'
command.
5.
Iteration from stage 1. to achieve the desired layout.
6.
Post-process CAD
Drawings
can be edited by the CAD program to improve the presentation. They
should position the panels and ribs on a reference template and print
the templates in an array of A4/A3 size paper or plotter.
FIGURE 1: How to
work with the program
5. COMPOSITION OF THE AIRFOIL FILES
The file of the
profile data must have the following structure:
Line 1: name of
the profile
Line 2: total
number of points defining the profile
Line 3: number
of points that form the extrados
(upper surface)
Line 4: number
of points that form the opening (if any)
Line 5: number
of points that form the intrados (lower surface)
Following lines:
X coordinate Y
coordinate of each point of the airfoil
The
coordinates are ordered starting at the trailing edge, covering the top
surface, passed through the leading edge and coming through the lower
surface and
again ending at
the trailing edge.
Important: The endpoint of the
extrados must exactly match the start in% of the opening (air inlet),
and the
starting point of the intrados must exactly match the end in% of the
opening (air outlet). Therefore the airfoil must be processed prior in
a CAD program
to
achieve this. Therefore if you want to vary the start and end points of
the air openings along span, you must detail specific profiles
for this.
Init and
end points of openings declared in leparagliding.txt file must be
consistent with the selected airfoils.
FIGURE 2:
Airfoils definition
Usually you must
define a profile of zero thickness for the final profile of the
wingtip.
It
is essential that the number of points of extrados, openings, and
intrados,
and all are exactly the same for all profiles defined in a
wing
model.
For gnulab2 two
profiles have been defined eg for gnulab2.txt wing and
airplan.txt to the end profile.
6.
COMPOSITION OF THE INPUT DATA FILE leparagliding.txt
Designing
the paraglider is simplified to editing the file leparagliding.txt
either
creating it from scratch or by editing an existing model.
All
lines that begin with the symbol "*" are comments that are not used by
the program, although you must maintain it to keep the sequence of
reading.
The units of
work planned for the data file are centimeters (cm), except sewing
allowances expressed in mm.
Next,
and
by section, we define the parameters to
enter in the data file.
Only are explained the line to complete, because the lines that begin with the asterisk
symbol * are comments that should be maintained as are, so that the
reading order is right.
First, it
indicates the type of data
to
enter (integer, real , text, or boolean (1 or 0)). Then, following the ":" , indicates
the object's data to write. It is
essential using
the sample file leparagliding.txt to
understand. The order, data type, and number of rows is essential for a correct reading
of the
data file.
SECTION
1: GEOMETRY
By lines, and regardless of the lines beginning with *
which are comments
or notes for help.
text
: Brand name
(between " ")
text
: Wing name
(between " ")
real : Drawing
scale
real : Wing
scale (1.0 usual value)
integer
:
Cells number
integer :
Ribs number
real, boolean
: Maximum torsion
angle
(washin) between central airfoil and tips, and parameter set to 1 or 0.
If
0 the washin will be done manually. (Figure 3)
text,
boolean : Paraglider type "ds" or "ss", and parameter set to 0
or 1. If
1
then leading edge triangles will be no rotated (ss paragliders)
integer
+ 8 reals:
For
each of the ribs, and considering an orthonormal system of axes XYZ
(Figure 4) .
oriented
in the following way:
X
axis along the wingspan
Y
axis along the central chord
Z axis growing vertical from the wing to the pilot
They are shown
in a horizontal line the following parameters:
integer
: rib number
real
: rib X
coordinate
real
: Y
coordinate of the leading edge
real
: Y
coordinate of the trailing edge
real
: X' coordinate
of the rib in its final position in space
real
: Z coordinate
of the rib in its final position in space
real
: the angle
of the rib to the vertical
real
: RP percentage
of chord to be held on the relative torsion of the airfoils
real
: washin in degrees defined
manually (if parameter is set to "0")
These
parameters can not be defined without a previous drawing, preferably in
a file of computer aided design CAD, in which the desired plant is
drawn to an appropriate scale, form lobe in elevation, and inclination
of the ribs. This drawing is one of the most basic and important design
(pre-process).
It
would be possible to generate this drawing by a geometric preprocessor
to read basic data from the wing desired number of cells, separation,
size, shape, edge and trailing by a few parameters defined to create
elliptical shapes. This
preprocessor has not been implemented, preferring to keep this
important part of design with a CAD program, to allow total freedom of
form in leading edge, trailing edge, and in the elevation, and
inclination of
the profiles. Any design is possible, normal wings, or bionic type,
with peaks in leading edge or ...
There is a
limitation of not being able to define airfoils in the center of
symmetry. To remedy this situation can be defined a virtual central
cell's with almost zero thickness.
Figure 3. Washin
Figure 4. Axis
and main paraglider geometric design
SECTION
2: AIRFOILS
In an orderly
manner for each rib, are written in a horizontal line:
integer : Number of rib
text : Name the file
containing the airfoil assigned to that rib
real : Percentage of
chord start of the air inlet
real : Percentage of chord end
of
the air inlet
boolean : Value 1 or 0 to
create
closed cells (two "0" followed indicates closed-cell)
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.
Note:
init and end points of the air openings are not fully implemented in
this version of the program and now is in the profile itself obliged
to include it.
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 5. Hole typoe 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 6. Hole type 2, ellipse or circle with central strip
Not use holes type 2 beacuse yet no
implemented !
If the hole is type 3, type in a horizontal line:
integer : 3
real : Distance from LE
to triangle in% chord
real : Distance from
the center of the triangle corner to the chord line in% of chord
real : Traingle base as% of
chord
real : Triangle heigth as% of
chord
real : Rotation angle
of the base
real : Radius of the smoothed
corners
real : 0. (not used)
real : 0. (not used)
Figure 7. Hole type 3 triangle
Continue:
integer : Initial rib for second lightening
configuration
integer : Final rib for second lightening
configuration
integer : Number of holes for the second
lightening configuration
Definition of
each hole in a horizontal line, as before.
And so on... (repeat pattern
for all types of lightening configurations)
SECTION
5: SKIN TENSION
The tension of
the top surface and lower surface panels is achieved by creating tapers
in the panels. The program allows you to define "over-wides" in 6
points along the edge of the panels. The transition between basis
points of overwide is linear.
In each of the
six lines are defined to indicate consecutively:
real :
Distance in% of
chord on the leading edge of extrados
real
: Extrados
over-wide corresponding in % of chord
real
: Distance in% of
chord on trailing edge
real
: Intrados
over-wide corresponding in%
of chord
FIGURE 8: Skin
tension
Then add two more lines with the
following parameterr (new in leparagliding 2.0):
real :
0.0114 (strain in
mini-ribs).
The
justification for this value is
obtained from the theory of
elasticity.
Leave the
default value in case
of doubt.
Figure 9. Ripstop
elasticity
real, real :
Number of points,
coeficient 0.0001 to 1.0
The justification for this line is complex. Is used to make fine adjustments
to the shape of the leading
edge for easy sewing.
Study conducted at the
request of a manufacturer of paragliders. Can be written, the default values given. Using the
coefficient 0.0001, this
setting has no effect.
Justification
of the
line in the
figure below:
Figure
10. Sewing corrections
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 in V-ribs
SECTION
7: SEWING MARCAGE
Indicate
the spacing in centimeters and the radius of the point, to make marks
on ribs and panels to match all items as accurately and thus able to
control that there is no slippage during sewing.
real, real, real : marks spacing, point radius, point
displacement
SECTION
8: ESTIMATING THE GENERAL ANGLE OF ATTACK
This
section defines the basic length of the lines and provides the general
draft of the wing, estimating the center of pressure and angle of
glide.
Be entered on
lines below:
real
: Finesse goal, according to the general proportions of the wing.
real
: Position of the wing center of pressure estimated as % of central cord
real
: Calage in% (distance from the leading edge point to the perpendicular
to the central chord from the pilot position)
real
: Riser basic length
real
: Basic length of lines (maillons - sail)
real
: Separation between main carabiners
FIGURE 12:
General AoA estimation
SECTION
9: DESCRIPTION OF LINES
It defines the following concepts by lines:
integer
: Control parameter with the following meanings
0 = lower branches lined only by geometric mean of the anchor points
1 = lower branches lined by weighting type 1 (not fully implemented yet)
2 = lower branches lined by weighting type 2 (not fully implemented yet)
integer
: Line plans number (2,3,4...)
Denotes the number of plans of lines that start from each of the risers
of the glider. Will be considered as many plans as risers. The "plans"
do not necessarily have lines in a plan, and may have different
alignments anchors in various rows (pyramid lines)
integer
: Paths number for first plan
11
integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i19, i11
Ramifications and levels
(i1)
number of branches (ramifications) of the path
(i2) branching level 1
(i3) order at level 1
(i4) level of ramification 2
(i5) order at level 2
(i6) level of ramification 3
(i7) order at level 3
(i8) branching level 4
(i9) order at level 4
(i10) anchor line (1 = A, 2 = B, 3
= C, 4 = c 5 = D, 6 = brake)
(i11) anchor rib number
- These are considered the ramifications from to the bottom to up. The
main riser are considered the branch level "1", the next line that
starts from maillons "2", the one above is the "3" ... and so on.
- Within a branch level are numbered consecutively in the same lines
from left to right 1,2,3,
- Path: Is any path through the ramifications, upward, started in the
main carabiner and ended in a sail anchor.
- With these definitions, this section should be written the array of
lines for each plan
- The first section number indicates the number of planes to be
considered.
- The next number indicates the total number of different paths in the
plane.
- Each line of the matrix is a "path"
- If there is no level 3 or 4 is denoted by "0"
- It is only allowed up to 4 levels of branching.
integer
: Paths number for second plan
11
integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i19, i11
Ramifications and levels
...
Do likewise with
the other plans of the paraglider line design. The example of clear
matrix writing is exposed in gnuLAB2 data file.
FIGURE 13:
Suspension
lines matrix
SECTION
10. BRAKES
real :
brake lenght
integer
: number of paths brake plane
The first number is the length in cm for the main brake cable, and
second number indicates the number of paths brake plane.
11
integers : i1, i2, i3, i4, i5, i6, i7, i8 ,i9, i19, 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
real : s1, s2, s3, s4, s5 (lengths along vault and from center
wing)
4
real : d1, d2, d3, d4, d5 (lengths increments in brake line)
Figure 14. 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 15:
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:
Figure
16. Mini-rib 1 (horizontal strap)
If it
is a "V-rib" mini-rib type:
Figure
17. Mini-rib 2 (V-rib)
If it
is a "full V-rib" type:
(not implemented yet!)
Figure
18. Mini-rib 3 (full V-rib
If it
is a "VH-rib" type:
(partially implemented!)
Figure
19. Mini-rib 4 (VH-rib)
SECTION
15:
EXTRADOS COLORS
integer :
number of ribs with marks
integer,
integer : first rib number, number of marks
integer, real,
0. : first mark, distance % from TE, 0.
integer, real,
0. : second mark, distance % from TE, 0.
...
integer,
integer : second rib number, number of marks
integer, real,
0. : first mark, distance % from TE, 0.
integer, real,
0. : second mark, distance % from TE, 0.
...
and so on...
Figure
20. Extrados colors
SECTION
16:
INTRADOS COLORS
Like
extrados colors (but not implemented yet). Write the minimal
configuration:
1
1 1
1 0. 0.
SECTION
17:
ADITIONAL RIB POINTS
With this option,
auxiliary points can be
drawn in the ribs.
Typically to mark mylars,
or start and end points
of the nylon rods.
integer : number of points
real, real
: x-coordinate % of chord, y coordinate % of chord (first point)
....
real, real :
x-coordinate % of chord, y coordinate % of chord (last point)
SECTION
18:
ELASTIC LINES CORRECTION
Option to estimate the elastic elongation of the lines in
normal flight configuration.
These elongations are subtracted from strictly
geometric length, so that in flight, are the exact lengths of project. Option fully
functional but still under
development. To calculate the elongation, we take into
account the loads on each
line, and the rigidly coefficient of each line, the elongation estimated by Hook's law: F = k·dx
real : load in
flight (kg)
real, real :
% load distribution in 2 lines rib
real, real, real
: % load distribution in 3 lines rib
real, real, real,
real : % load distribution in 4 lines rib
real, real, real, real, real : % load
distribution in 5 lines rib
integer, real,
real, real, 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
7.
FUTURE DEVELOPMENTS
The
author of the program maintains the files leparagliding.f and
leparagliding.txt
constantly evolving, and improvements will be added
in future releases.
- Optional
pre-processor optional for basic geometry (planform and vault)
-
Dynamic definition of points of entry and exit of air inlets,
directly from the data file without having to coordinate with the
definition from the airfoil files.
- Improving VH ribs design (three cell)
- V-rib (full)
- Improvements on lines elastic calculus
- Much better plans presentation
It is very recommended reading and
understanding the file example file leparagliding.txt,
following this guide.
Pere Casellas
pere at
laboratoridenvol dot com
Teià,
January 2012
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