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BHL4
BARRETINA HYPER LITE 4

BHL4
BHL4
Figure 1. Planform 3D view

BHL4
Figure 2. 3D view

1. DESCRIPTION

BHL4 is a single skin paraglider with a moderate 4.69 aspect ratio. An updated and improved version of the BHL1 (Batlite), using the experiences adquired with previous monosurfaces. The shape of the profile is the same as BHL2, but with a different distribution of triangles. In this case, we use 5 points of suspension for the profile, with the intention to better define the trailing edge. There are two closed cells near the wingtips with an elliptical inlet as BHL2-evo. The shape of the vault is the same as BHL3. The list of lines proposed initially is the one that comes out of the program, without modify. The nose  will be rigidified with two rods (contour and vertical compresion rod). The skin tension is increased with a variation more pronounced between centre and extremes, and more smooth (using a new subroutine for skin tension). Finally, the brakes will be fixed to the trailing edge with a small "V" ribbon, to shorten the trailing edge when braking and eliminate part of the ovalization and creating a more defined flap. All of these details should provide a simple, efficient and fun single skin paraglider. Using the same solutions, but with a more elongated planform, there is the BHL5.

2. TECHNICAL ESPECIFICATIONS BHL4


 XXS
 XS
 S
 M
 M-L
Model
 BHL4-16
 BHL4-20
 BHL4-20
 BHL4-22
 BHL4-24
Surface
 16 m2
 18 m2
 20 m2
 22 m2
 24.04 m2
Flat span
 8.66 m
 9.19 m
 9.69 m
 10.16 m
 10.62 m
Flat AR
 4.69
 4.69
 4.69
 4.69
 4.69
Panels
 35
 35
 35
 35
 35
Closed cells
 2 in wingtip, with one elliptical inlet
Weight range
 -
 -
 -
 -
 -
Anchors per rib
 5, and 4 (near tips)
Risers
 4
Top surface
 ripstop 40 gr/m2
Ribs
 ripstop 40 gr/m2 hard
Certification
 No


3. DATA FILES AND PLANS

LEparagliding-3.17 input and output files and DXF files
pre-procesor and leparagliding
data files
 pre-data.txt  leparagliding.txt
Airfoils
 bhl-5p.txt  bhl4-4p.txt  bhl-tube.txt
Output txt files
 lep-out.txt lines.txt
PDF descriptive plans
 BHL4-24
PDF A4
 BHL4-24_A4
All files in one zip including DXF plans
Version 2022-01-06
 BHL4-16.zip
BHL4-18.zip
BHL4-20.zip
BHL4-22.zip
BHL4-24.zip  (includes PDF to print A4)

Skin tension law
Figure 3. Skin tension law data.txt gnuplot
Figure 4. Airfoils
bhl-5p
 bhl-4p
 bhl-tube


4. CONSTRUCTION
Suluk 2
Special version of BHL4 16 m2 "Suluk 2", by Julien Caquineau. Several test flights took place in December 2021 and January 2022,
despite the cold and the two and a half hours of light in the Greenlandic winter.

In December 2021 Julien Caquineau in Greenland built a prototype of the BHL4 model of 16 m2 with three risers and profiles modified with parabolic shapes "Suluk 2". Julien measured +36 km/h hands up with 35% calage setting, total weight in flight 85kg. The first flights revealed that the 35% calage setting was too optimistic, and it is advisable to change the entire lines set to 42% setting. An additional washin on the wing tips is also recommended. The indicated adjustements have already been incorporated into the 2022 version plans.

Proposed change for the washin:

 Rib - washin
 ---------------------
 1        0.000
 2        0.000
 3        0.000 
 4        0.000
 5        0.000
 6        0.000
 7        0.000
 8        0.000
 9        0.750
10       1.750
11       2.800
12       4.000
13       5.000
14       6.000
15       7.500
16       9.000
17      10.500
18      12.000 

The Suluk2 prototype in the December 2021 version incorporated a distribution of lines into three risers A, B, C+ D+E. Certain vibrations observed at high speed, indicated that it was better to modify the distribution in A+B, C, D+E. Indeed, with the new lines distribution and calage, the vibrations disappear.

1
2022-02-06 (1)
 3
2022-02-06 (2)
4
2022-02-06 (3)

The test with the new lines set was carried out at a temperature of -30º (!), using one of the rare windows of "good weather" available during these days of February 2022. It is planned to send the wing to Switzerland for an SIV test.
The wing already has the markers to display the 50% and 75% collapses :-)

s2t
July 2022, Suluk 2 is now in Teià for study in the Laboratory. Many thanks to Julien Caquineau for sending his prototype for study!

1
 1
1 1
August 2022, Suluk 2 in Darnius Lake slopes. Testing trimmers.

I am very grateful to Julien Caquineau for having built this model and carried out the flight tests which allow us to discover the necessary settings. Thanks to all the adjustments made by pilots and manufacturers, we can improve the wings.


Prototype BHL4 31 m2 HERCULES by Lance Kraftenberg


LAB NOTE: Build a paraglider at home is a very complicated task (even simple skin), 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.

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