LEhanggliding is a parametric program for hang glider designs. The main idea is
write all the numerical parameters which serve to define the
entire hangglider (structure, sail, parts) in .txt data files, and use some automation
programs to draw all the pieces and the plans.
We have selected use
two programming languages for this task: Fortran and OpenSCAD.
The Fortran program is used to read the data file, draw the plans,
print a report, and even other files to be used as data in OpenSCAD.
Using OpenSCAD we can model realistic 3D parts of the hang glider. The
functionality of the
current version of the program is still not complete but the system is
and We can imagine the whole system working. Is necessary continue the
work of programming and documentation.
PART 1. LEHG-F-0.11 (FORTRAN)
All the hang glider parameters can be written to a data.txt text file, and the program is responsible for drawing the wing plans in dxf format
and other documents. The program draws a single-line scheme in 2D and
3D, simple but with great precision. Currently, the program version 0.11 only draws
the dxf shape in plan view, but with many parameters of representation. The
leading edges can be modeled in deformed shape, acording expected sail tension or forced by deflectors.
The manual for entering the data has not yet been written, but the
structure of the data file is obvious. And most of the data can be
interpreted by reading the file itself, and comparing the four provided
examples. Important to remember that the units are cm for longitudes
and degrees degrees (0-360║) for angles.
Some examples below, the geometries correspond to real wings.
Fig 1. Four hang glider examples
Download LEHG-F-0.11 including source code (lehg.f), GNU/Linux executable file (a.out), readme.txt, and all data and dxf files.
PART 2) LEHG-O-0.2 (OpenSCAD)
The idea is to draw each elementary piece in a module. From the
smallest washer, screw, bracket, plate,... to tubing and wire. The
majority of the pieces will be parametric (a few numeric values will
control its shape and dimensions). A main routine will be in charge of
assigning parameters and position (assembly) in space each of the
elementary pieces. Some pieces of regular use may be inserted in the
form of an object .stl to reduce the work of construction of the
modules. Openscad allows us to export easily to .stl each of the parts
New drawings (october 2020):
Fig 2. Nose area usig nose plates, saddles, tubes, and nose rail
Figure 3. Separate pieces through a single parameter "dz"
Figure 4. Bracket and keel saddle type 1 (fully parametric)
convention, we have used a system of orthonormal axes where the y-axis
follows the direction of the keel, and z the vertical direction. We
consider as origin of coordinates the center of the front bolt of the
nose plate. Base units is mm. As in october 2020, we currently may use
the following modules:
Tube type 2 along Y axis, and multiholes (mod_tube2.scad):
hole_type=1 (= one hole)
hole_type=2 (=two holes aligned with the axis of the tube)
Keel bottom bracket type 1 (mod_kbbracket1.scad):
Keel saddle type 1 (mod_keelsaddle1.scad):
Saddle type 1 (mod_saddle1.scad):
Nose plate type 1 (mod_noseplate1.scad):
a=distance X to LE bolt
b=distance Y to LE bolt
c=distance Y to second bolt
r=radious of the "hull" operation (the plate is the convex envelope of circles of radius r, centered at each bolt).
Main assembly program is LEHG-0.2.scad
Notes and schemes here: page1 page2 page3 page4 page5 page6
Download all modules and main program here: LEHG-0.2.scad
Figure 5. openSCAD code generator, first versions
Figure 6. Nose plates and capends.