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gnu "C"
Planform
Figure 1. Planform

 C
Figure 2. 3D view

1. DESCRIPTION

gnuC or "C" is a 60 cell, 6.25 aspect ratio, high performance paraglider. Incorporates the latest technical advances (shark nose, 3Dshaping, three rows of lines, reduced total length of lines. Project started in winter 2016-2017 using LEparagliding 2.60. Latest version (size L) updated to 2021 using leparagliding 3.16. The construction of this paraglider is not simple and involves a lot of work, as it has many parts and a complex internal geometry.


2. TECHNICAL DATA

gnuC 2021
gnuC (2021 version). 60 cells, aspect ratio 6.25

Size
 M
 L
Flat area
 25.22 m2
 27.00 m2
Flat span
 12.55 m
 12.99
Flat A/R
 6.25
 6.25
Projected area
 21.49 m2
 23.01
Projected span
 10.13 m
 10.48
Flat A/R
 4.77
 4.77
Flattening
 0.15
 0.15
Cells
 60
 60
Airfoil
 gnuC-c1
shark nose candidate 1
 gnuC-c1
shark nose candidate 1
Line lenght
 289.01 m
 298.94 m
Lines
 3(A)+3(B)+4(C)
Risers
 3 ( true tree-liner)
Mini-ribs (TE)
 yes
V-ribs
 diagonals type 1, 3, and 6
 diagonals type 1, 3, 6, and 16


gnuC candidate1
Figure 3. gnuC-c1.dat shark nose airfoil, candidate 1

Internal ribs
Figure 4. V-ribs (4 cells jump)


3. DATA AND PLANS

M 25 m2 (project 2016-11-20)
 L  27 m2 (project 2021)
pre-processor data
 pre-data.txt


geometry.dxf
lep data
 leparagliding.txt leparagliding.txt
main airfoil
 gnuC-c1.txt
gnuC-c1.txt
tip airfoil
 gnuC-t.txt gnuC-c1.txt
DXF2000 2D
 gnuC-2D.dxf
DXF2000 3D
 gnuC-3D.dxf

lep-out.txt
lep-out.txt

lines.txt lines.txt
PDF report
20211011 gnuC-27.pdf
All project and
files in one zip
20211010 gnuC-27.zip

4. CONSTRUCTION

In october 2021 one prototype started (size M) and another in preparation (size L).
April 2023: Prototype in flight by Zhu Guoqiang


5. SCREENSHOTS

1 Captura_2021-10-10_18-27-38
Captura_2021-10-10_18-27-38
 2 Captura_2021-10-10_18-29-56
Captura_2021-10-10_18-29-56
3 Captura_2021-10-10_18-31-00
Captura_2021-10-10_18-31-00
 4 Captura_2021-10-10_18-31-49
Captura_2021-10-10_18-31-49
5 Captura_2021-10-10_18-32-26
Captura_2021-10-10_18-32-26
 6 Captura_2021-10-10_18-33-07
Captura_2021-10-10_18-33-07
7 Captura_2021-10-10_18-34-10
Captura_2021-10-10_18-34-10
 8 Captura_2021-10-10_18-35-09
Captura_2021-10-10_18-35-09
9 Captura_2021-10-10_18-36-08
Captura_2021-10-10_18-36-08
 10 Captura_2021-10-10_18-38-14
Captura_2021-10-10_18-38-14


5. COMPUTATIONAL FLUID DYNAMICS gnuC AITFOIL ANALISYS

CFD Study of the gnuC airfoil, by Francois De Villiers (Cape Town, South Africa)
0
1. Xfoil (XFLR5) gnuC at zero degree.
 1
2. First CFD of closed sharknose compared to xfoil at zero degrees, re=1e6, too small domain, no mesh optimization but already good comparison on CP coefficient. The spikes is due to rough coordinates in gnuc-candidate, both visible in xfoil and cfd. Slight Diff in cp might just be due to multiple segment 2nd order curve fitting from my side.
2
3. Pressure plot
 3
4. Gnuc-candidate1 at 8 degrees angle of attack showing internal flow circulations
4
5. Just a quick run... gnuC Removing the bottom part of the current sharknose... relative to double skin the single skin L/D dropped by half. Lift almost double for same angle of attack.



LAB NOTE: Build a paraglider at home is a very complicated task , and requires many hours of work. Previous experience is required, and very inventive. As always remember that: The free flight implies risks that can only be known and they can be controled with a suitable formation on the part of a recognized school. Not test wings without knowing their functioning. The construction and test of experimental wings without certifying requires deep knowledge of what is being made.