Surface parachute
A surface parachute , also paraglider , in the form of a paraglider , is an air-filled, multi-chamber, textile wing that is designed for use as a parachute and is connected to the payload or the parachutist by a system of lines and straps. After being shaped like a wing, these are also referred to as "mattresses".
properties
In comparison to other round canopy parachute systems, wing parachutes have a significantly better gliding ability and controllability. They can therefore be used to make very smooth precision landings by braking forwards.
Paragliders differ from paragliders in that they can be opened in the air after a free fall phase. On the one hand, paragliders are designed to be more stable and, on the other hand, they have a delay system to avoid sudden canopy deployment - today this is usually a slider , previously also a circumferential reefing line or a diaper that held the canopy base together. The processing and the material of paragliders is not designed for a sudden opening after free fall.
In general, however, paragliders do not achieve the glide ratio of paragliders. Part of the paraglider are the opening retarder and the inner packaging today mostly as a pod , rarely as a short-pack hose , as well as the hand-deploy or an auxiliary parachute with a pull-up cable. The main straps, on the other hand, belong to the outer packaging, the container, and also remain on this when the cap is replaced. The short straps located on the parachute canopy as an extension of the suspension line bundle, one per cell, serve as auxiliary packing straps in order to be able to pack the parachute canopy in an orderly manner in the side pack. These have consecutive colors that are repeated once.
Paragliders fly very stable due to the spatial separation of the center of gravity (near the payload) and the center of lift (in the textile wing). Changes in direction are initiated via control lines attached to the left and right of the paraglider's trailing edge. They are used to deform the paraglider asymmetrically. Due to the negative inclination of the surface parachute to the horizon, the parachute glides forward through the air flowing past the parachute at different speeds. As a result, the control lines are also used for braking and the speed of the parachute is slowed down or canceled down to zero in headwinds.
Size and burden
The size of wing parachutes is traditionally measured in sqft . Tandem umbrellas are around 330 to 400 sq. Feet, student umbrellas are 200 to 300 sq. Feet, and experienced jumpers fly with umbrellas up to under 84 sq. The parachute load (wing load) is between 0.8 and 1.1 lbs / sqft for students . A wingload of up to 1.65 lbs / sqft is common . Above that begins the area that can only be considered by the most experienced jumpers.
For jumpers up to 300 jumps, a wingload of a maximum of 1.3 lbs / sqft is recommended.
Working group ADS
The most important scientific contact point for all questions about parachutes and paragliders is the ADS (Aerodynamic Decelerator Systems) working group of the AIAA (American Institute of Aeronautics and Astronautics). The conferences that take place every two years and the associated reports reflect the latest research results and projects.
Development history
For a long time, parachutes were mostly round canopies with a relatively high rate of descent that were either impossible or difficult to control . Today, round canopy parachutes are basically only used where controllability is largely useless or even undesirable. This applies (with exceptions) mainly to cargo and rescue parachutes . In most other applications, and especially in parachuting, parachutes are common today, the development of which began in the 50s and 60s.
At the beginning of the 1960s, in connection with the ambitious space plans of the USA and the then USSR , the development of parachutes was promoted in order to be able to better bring the landing capsules of spaceships back to earth after the end of the mission.
After the further development of the " Rogallo " and "multi-cell concepts", which had already been pursued in the 1950s, a patent was applied for in 1962 with the Para Commander US, a controllable high-performance round cap.
On January 1, 1963, Domina Jalbert followed suit with the patent for a special multi-cell parachute.
In March 1963, Jalbert published his knowledge that in order to effectively increase performance, one would have to abandon the parabolic shape of the parachute and use air-filled cells in the shape of a wing instead.
On October 1, 1964, Jalbert registered a corresponding box-shaped or mattress-shaped multi-cell parachute concept (parafoil), with which he took up Rogallo's earlier ideas in principle. In the same year a first motorized version of Nicolaides flew (see also paramotor ).
Since NASA was skeptical about double-wing parachute systems at the time, Dave Barish developed a rectangular single- wing parachute (see also Sailwing ) and also patented it in 1964. Its further development from 1965, the Sailwing, can be considered the first paraglider in history.
After Steve Snyder had developed opening delays (sliders) for Jalbert's parafoil, Paul Poppenhager was probably able to make the first parachute jump with a parafoil. In 1967 jumps were made with it, but apparently still with an "open umbrella" or with immediate opening and only further developments of the opening delay by Snyder finally made free-fall-suitable umbrellas possible. Also in 1967, Walter Neumark probably carried out the first foot launch with a parafoil (see also paragliding and mountain flying ).
As early as 1968, the Golden Knights, a well-known American parachutist troop, switched from the Rogallo-type parawing to a parafoil parachute.
In the course of the following ten years, the new mattress parachutes established themselves worldwide and around 1980 had largely replaced the earlier round cap systems in parachuting . In training, since the 1990s, these have increasingly been carried out with school parachute systems, also with forced release. Until then, round-cap parachutes were used and the trained jumper then retrained. The mattress umbrellas - and not the earlier, technically different first paraglider Barishs from 1965 - also represented the basis for the development of the new paragliding sport .
For the field of military parachuting see Military Freefall .
Applications
More recently, self-steering load parachute systems based on paragliders, such as the American Joint Precision Airdrop System and the German Cassidian ParaLander, have been developed that use satellite navigation ( GPS ) to independently navigate to a predetermined target and transport a payload to a target point. This application is interesting for the inexpensive and precise repatriation of space loads and the delivery of humanitarian goods. One application was found in the NASA X-38 space rescue package , where the world's largest paraglider was used during testing. SpaceX also uses such a system for landing the payload fairings of rockets.
Individual evidence
- ↑ NZAerosports: Information on Choosing a Canopy and Wing Loadings. In: Choosing a canopy. NZAerosports, accessed November 3, 2018 .
- ↑ DFV: Screen selection based on experience and jump frequency. In: Wingload table screen selection. DFV, accessed on November 3, 2018 .