Equipment
Wing
Parts of a paraglider
The paraglider wing or canopy is known in aeronautical engineering as a ram-air airfoil, or parafoil. Such wings comprise two layers of fabric which are connected to internal supporting material in such a way as to form a row of cells. By leaving most of the cells open only at the leading edge, incoming air (ram-air pressure) keeps the wing inflated, thus maintaining its shape. When inflated, the wing’s cross-section has the typical teardrop aerofoil shape.
In some modern paragliders (from the 1990s onwards), especially higher performance wings, some of the cells of the leading edge are closed to form a cleaner aerodynamic airfoil. Like the wingtips, these cells are kept inflated by the internal pressure of the wing Wings Infos.
The pilot is supported underneath the wing by a network of lines. The lines are gathered into two sets as left and right risers. The risers collect the lines in rows from front to back in either 3 or 4 rows, distributing load as in a whippletree. The risers are connected to the pilot’s harness by two carabiners.
Paraglider wings typically have an area of 2035 square metres (220380 sq ft) with a span of 812 metres (2639 ft), and weigh 37 kilograms (6.615 lb). Combined weight of wing, harness, reserve, instruments, helmet, etc. is around 1218 kilograms (2640 lb).
The glide ratio of paragliders ranges from 8:1 for recreational wings, to about 11:1 for modern competition models[citation needed]. For comparison, a typical skydiving parachute will achieve about 3:1 glide. A hang glider will achieve about 15:1 glide. An idling (gliding) Cessna 152 will achieve 9:1. Some sailplanes can achieve a glide ratio of up to 72:1.
The speed range of paragliders is typically 2060 kilometres per hour (1237 mph), from stall speed to maximum speed. Beginner wings will be in the lower part of this range, high-performance wings in the upper part of the range. The range for safe flying will be somewhat smaller.
Modern paraglider wings are made of high-performance non-porous fabrics such as OLKS from Gelvenor, with Dyneema/Spectra or Kevlar/Aramid lines.
For storage and carrying, the wing is usually folded into a stuffsack (bag), which can then be stowed in a large backpack along with the harness. For pilots who may not want the added weight or fuss of a backpack, some modern harnesses include the ability to turn the harness inside out such that it becomes a backpack.
Tandem paragliders, designed to carry the pilot and one passenger, are larger but otherwise similar. They usually fly faster with higher trim speeds, are more resistant to collapse, and have a slightly higher sink rate compared to solo paragliders.
Since 2000 Juan Salvadori in Argentina has been exploring a variant wing termed Paramontante that involves some firm beams. In April 2009 Pere Casellas has joined in a collaboration with Juan Salvadori for polishing the paramontante. Laboratori d’envol Paramontante
Harness
Pilot with harness (light blue) doing reverse launch
The pilot is loosely and comfortably buckled into a harness which offers support in both the standing and sitting positions. Modern harnesses are designed to be as comfortable as a lounge chair in the sitting position. Many harnesses even have an adjustable ‘lumbar support’. A reserve parachute is also typically connected to a paragliding harness.
The primary purpose of parachutes (including skydiving canopies) is for descending, as when jumping out of an aircraft or dropping cargo. In contrast, the primary purpose of paragliders is for ascending. Paragliders are categorized as “ascending parachutes” by canopy manufacturers worldwide, and are designed for “free flying” meaning flight without a tether (for an example of tethered flight, see parasailing). However, in areas without high launch points, paragliders may be towed aloft by a ground vehicle or a stationary winch, after which they are released, creating much the same effect as a mountain launch. Such tethered launches can give a paraglider pilot a higher starting point than many mountains do, offering similar opportunities to catch thermals and to remain airborne by “thermaling” and other forms of lift. As free flight, paragliding requires the significant skill and training required for aircraft control, including aeronautical theory, meteorological knowledge and forecasting, personal/emotional safety considerations, adherence to applicable Federal Aviation Regulations (US), and knowledge of equipment care and maintenance.
Instruments
Most pilots use variometers, radios, and, increasingly, GPS units when flying.
Variometer
Vario-altimeter
Birds are highly sensitive to atmospheric pressure, and can tell when they are in rising or sinking air. People can sense the acceleration when they first hit a thermal, but cannot detect the difference between constant rising air and constant sinking air, so turn to technology to help. Modern variometers are capable of detecting rates of climb or sink of 1 cm per second, such is the case of the Flymaster B1 which uses extremely low noise electronics and complex algorithms to detect such minute changes in air pressure.
A variometer indicates climb-rate (or sink-rate) with short audio signals (beeps, which increase in pitch and tempo during ascent, and a droning sound, which gets deeper as the rate of descent increases) and/or a visual display. It also shows altitude: either above takeoff, above sea level, or (at higher altitudes) “flight level.”
The main purpose of a variometer is in helping a pilot find and stay in the “core” of a thermal to maximise height gain and, conversely, to indicate when a pilot is in sinking air and needs to find rising air.
The more advanced variometers have an integrated GPS. This is not only more convenient, but also allows one to record the flight in three dimensions. The track of the flight is digitally signed and stored and can be downloaded after the landing. Digitally signed tracks can be used as proof for record claims, replacing the ‘old’ method of photo documentation.
2m-band radio
Radio
Pilots use radio for training purposes, for communicating with other pilots in the air, particularly when travelling together on cross-country flights, and for reporting the location of landing.
Radios used are PTT (push-to-talk) transceivers, normally operating in or around the FM VHF 2-metre band (144148 MHz). The “2 Meter” band is an amateur radio band, sometimes used for interpersonal communications, and Aviation Frequencies are usually 108MHz to 136MHz. Usually a microphone is incorporated in the helmet, and the PTT switch is either fixed to the outside of the helmet, or strapped to a finger.
GPS
GPS (global positioning system) is a necessary accessory when flying competitions, where it has to be demonstrated that way-points have been correctly passed.
It can also be interesting to view a GPS track of a flight when back on the ground, to analyze flying technique. Computer software is available which allows various different analyses of GPS tracks (e.g. CompeGPS, See You).
Other uses include being able to determine drift due to the prevailing wind when flying at altitude, providing position information to allow restricted airspace to be avoided, and identifying one location for retrieval teams after landing-out in unfamiliar territory.
More recently, the use of GPS data, linked to a computer, has enabled pilots to share 3D tracks of their flights on Google Earth. This fascinating insight allows comparisons between competing pilots to be made in a detailed ‘post-flight’ analysis.
Control
Speedbar mechanism.
Brakes: Controls held in each of the pilot hands connect to the trailing edge of the left and right sides of the wing. These controls are called ‘brakes’ and provide the primary and most general means of control in a paraglider. The brakes are used to adjust speed, to steer (in addition to weight-shift), and flare (during landing).
Weight Shift: In addition to manipulating the brakes, a paraglider pilot must also lean in order to steer properly. Such ‘weight-shifting’ can also be used for more limited steering when brake use is unavailable, such as when under ‘big ears’ (see below). More advanced control techniques may also involve weight-shifting.
Speed Bar: A kind of foot control called the ‘speed bar’ (also ‘accelerator’) attaches to the paragliding harness and connects to the leading edge of the paraglider wing, usually through a system of at least two pulleys (see animation in margin). This control is used to increase speed, and does so by decreasing the wing’s angle of attack. This control is necessary because the brakes can only slow the wing from what is called ‘trim speed’ (no brakes applied). The accelerator is needed to go faster than this.
More advanced means of control can be obtained by manipulating the paraglider’s risers or lines directly:
Most commonly, the lines connecting to the outermost points of the wing’s leading edge can be used to induce the wingtips to fold under. The technique, known as ‘big ears’, is used to increase rate of descent (see picture).
The risers connecting to the rear of the wing can also be manipulated for steering if the brakes have been severed or are otherwise unavailable.
In a ‘B-line stall’, the second set of risers from the leading-edge/front is gently pulled down to put a crease across the lower surface of the wing (this will also distort the upper surface) acting as an ‘air brake’ significantly reducing airspeed. The combination of reduced forward airspeed and increased vertical airspeed destroys the laminar flow of air over the aerofoil, dramatically reducing the lift produced by the canopy, thus inducing a higher rate of descent.
Fast Descents
Big Ears, Rocky Point, NY.
Problems with etting down can occur when the lift situation is very good or when the weather changes unexpectedly. There are three possibilities of rapidly reducing altitude in such situations, each of which has benefits and issues to be aware of:
Big ears induces descent rates of 2m/s or so. It is the most controllable of the techniques, and the easiest for beginners to learn.
A B-line stall induces descent rates of 5m/s or so. It increases loading on parts of the wing (the pilot’s weight is mostly on the B-lines, instead of spread across all the lines). There is not a risk of the pilot becoming disoriented as a result of using this technique.
A spiral dive offers the fastest rate of descent, at 10-15m/sec. It places greater loads on the wing than other techniques do, and requires the highest level of skill from the pilot to execute safely.
Big Ears
By pulling on the outer A-lines the wing tips of the glider can be folded in. This method drastically deteriorates the glide angle with only a small decrease in forward speed. The effectiveness of this technique can be increased by using the speed system at the same time.
