China
Africa
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Parachutes and Parafoils in Agricultural Crop Production
Published in K. R. Krishna, Aerial Robotics in Agriculture, 2021
A brief description of parts and their purpose is as follows: Pilot chute: It is a small parachute located on top of the main canopy. It opens the parachute;Bridle: It is used to connect pilot chute and main parachute;Vent: It allows the escape of air from main parachute. The vent avoids stray loss of air from outside the canopy. Which otherwise can cause destabilization and wobbling in the air.Canopy: This is the main part of the parachute and it is made of special type of nylon or silk or tarpaulin. As the parachute size goes up, the number of gores increases. This allows more connection points to the parachute and keeps the load capability per shroud line more constant. Small chutes have just 8 gores, while a 192 inch parachute has 18 (Fruitychutes LLC., 2018 a,b).Skirt: It forms the lower part of the parachute’s canopy. Its edges have to be sewn without any tear.Suspension lines: These are threads made of tough material and are attached to skirt of the canopy. They help in distributing the weight of payload (e.g., a person, large container, aluminum cage for sensors, etc.);Links: They are crucial parts that connect the suspension lines to risers;Risers: They connect the links to harness;Control lines: They are useful in steering and braking the parachute/ parafoil.Harness: It is used to tightly fasten the paratrooper. A container is used to hold all the parts of the parachute, when not in use. It is also held in a cotton backpack. The pack is fastened to the parachutist with a harness. It is specially constructed so that the forces of deceleration, gravity, and wind are transmitted to the wearer’s body as safely and comfortably as possible. Modern parachutes are nearly always worn on the back and are rarely worn on the chest.
Effect of fabric construction, seam angle, and impact force on the performance of the parachute canopy
Published in The Journal of The Textile Institute, 2023
Gyana Ranjan Behera, Monica Sikka, Arunangshu Mukhopadhyay
The various properties of the fabric have been evaluated (Table 1), following ASTM Standards, i.e. ASTM D3775-17e1 for warp-weft yarn density, ASTM D1059-17 for linear density of warp-weft yarns, ASTM D1777-96 for fabric thickness, ASTM D3776 for mass density (gsm), and ASTM D3883-04 for crimp %. The type of seam used to join gores and panels in a circular parachute canopy is an important part of the entire parachute before its practical applications. The mostly used French fell (Duncan, 2015) LSc2 seam (Figure 2) is used to stitch the present fabric samples. LSc2 seam (as described in ASTM D D6193-16, 2020) is prepared by folding in and interlapping the edges of two plies of fabric with the application of two rows of stitching to conceal the edges. The specimen dimension in the present small-scale tensile impact testing is shown in Figure 3 where the drop height and length are 300 mm, and the total width is 140 mm which comprises of ungripped width of 20 mm on both sides of the specimen (Behera et al., 2022). The stitched ripstop and plain-woven fabric samples at 0° and 45° seam bias angles are shown in Figure 4.