Forums:Paragliding FAQs

Aerodynamics: The study of the movement of a body through the air, such as aparaglider’s wing.Actual Wing area: Span x average chord.Advention fog: Formed when a humid air mass moves in light-to-moderate windsover a cold region such as the sea. This type of fog is commonly found in oceanterritory and coastal regions.Agl: Abbreviation for above ground level. Airfoil: A curved surface designed to generate lift when moving through the air.Airspeed: The velocity of the glider through the air.Airspeed indicator: An instrument for measuring airspeed.Aircraft Approach: Forming a U-shape by flying downwind, crosswind then headwind to the landing field. Altimeter: An instrument for measuring altitude above a predetermined point.

Atmospheric pressure: The atmosphere's mass downward by gravity, measuredin Hectopascals (hPa), or formerly in Millibars (mb).Angle of attack: Is the angle the relative wind makes with the chord of an airfoil.

Anchoring: Assistance by a person during launch.Alpine Launch: Forward launch with the pilot having the wing behind his body.

Angle of descent: Is the angle your path makes with the horizon and is the sameas flight angle. 12Approach figure 8: The landing area is reached by making figure 8 turns beforeor above the landing field.

Aspect ratio: Ratio of the span to the chord or span divided by surface area. Spanx span/actual wing area.Ass Wipe: Downwind landing, still in your seat.

Asymmetrical Collapse: An uneven collapse of the wing. One side of the wing isinflated and the collapsed part is deflated.Attitude angle: Is the angle between the chord of the wing and the horizon. It ispositive above and negative below the said horizon.Average rate: Is a constant at which the air’s temperature drops with altitude by0.65o C per 100 meters.

Bank angle: The angle the wings make with the horizontal in a roll.

Beaufort Scale: Observed effects of the wind described by a British captain.Big Ears: Intentional collapse of the wing tips while in flight.

Buys Ballot's Law: In the Northern Hemisphere, if one stands with his back to thewind the area of low pressure is to his left. In the Southern Hemisphere the reverseis true.

Bernoulli's principle: Physical principle formulated by Daniel Bernoulli that statesthat as the speed of a moving fluid (liquid or gas) increases the pressure within thefluid decreases.

Brakes: The controls of a paraglider that pull down the trailing edge.

Camel's back: Waterbag with a tube for inflight use.Camber: The amount of curvature on the upper surface of an airfoil.

Canopy: The material or "sail" of a paraglider that forms the airfoil or wing.

Cap Cloud: Clouds produced at mountain peaks due to the lifting of the air overthe mountain.

Carabiners: Are rings or loops usually made from steel or aluminum alloy.

Cat's cradle: Competition task with multiple turn points, which the pilot has to flyat his own route.

Cells: The individual inflated units of a canopy between suspension lines.Center of gravity: The point along a wing where all the weight is suspended.Chord: Measurement of an airfoil from the leading edge to the trailing edge.Cocooned: To be fully wrapped in the canopy while in flight.Coordinated turn: A turn at a steady state in which a slip or a stall does not occur.Conduction: The transfer of heat during collisions among molecules. Heat is trans¬ferred from warm objects to cold ones, the rate is proportional to their tempera¬ture difference and their heat conductivity.

Convection: The transfer of heat by large movements of a gas or liquid.Convergence: When a moving air mass meets another moving airmass.

Cravattage: The word comes from the French word "cravatte" and means bow tie.As a term, it refers to a form of the wing where the material of the wing tip isentangled in the lines.Cross-ports: The holes in ribs that allow equalization of pressure between cells.

Crosswind: A wind angling across the normal launch or flight path.Cross-country: Flying beyond the normal landing field by using lift encounteredalong the way.Deep stall: An emergency situation whereby a glider descends with little or noforward speed.Dew point: Represents the temperature at which the atmospheric air becomessaturated as it cools.

Downwind: Flying in the same direction as the wind (flying with a tailwind). Drag: The energy loss on the glider due to the friction and mass of the air.

Dry adiabatic lapse rate: Is a constant which gives us the rate at which a rising airmass cools. This constant is 1oC per 100 meters of height (5.5oF per 1,000 ft).

Dust devils: Are caused by a tight swirl of whirling air which results when a ther¬mal lifts off suddenly and air, with a slight rotation, rushes in below it.

Dynamic stall: A stall produced by pulling the brakes rapidly so that the pilotswings forward and aggravates the stall.

Electromagnetic Energy: Energy that is propagated by electric and magneticfields. Matter is not required to transfer of this type of energy known also as radi¬ant energy.End-cell closure: A problem during inflation whereby the ends of the canopy donot open properly.

Evaporative Cooling: Energy is required to change the phase of water from aliquid to a vapor, which results in a cooling of the surrounding environment.Foehn wind: Is a warm and dry wind, encountered on the leeside of a hill ormountain where lifting of the air mass causes precipitation.Flare: The process by which forward speed is exchanged for lift during landing.Flight check: An inspection for tangled lines or end-cell closures.Flight angle: Is the angle between the horizon and the flight direction or path.Front: In meteorology, it is the boundary which separates warm and cool air masses.Geostrophic Wind: Is the wind that blows due to the influence of ground friction.Glide angle: The angle between the glide path and the horizontal.Gliding: Flight that continues from an elevated point to a lower point.Glide path: The flight path of a glider.Glider: An aircraft that remains in flight solely through the energy of gravity.Glide Ratio: The horizontal distance traveled relative to the amount of vertical drop.Gores: The separate panels of a parachute equivalent to cells on a paraglider.GPS: Global Positioning system by Satelite.Grabbing: Is the technique correcting the shift in ground track due to cross wind.Gradient Wind: When geostrophic wind is moving in a curved trajectory, on ap¬proaching the core of a low, it will experience a counteracting centrifugal force,which will diminish or moderate it.Ground speed: The velocity of a glider over the ground. This is different fromairspeed if any wind is present.Ground gripper: Non-pilot.Gross weight: Total weight of the glider and the heaviest allowed payload (pilot).Gumby: When a pilot fails to get into the seat.Harness: A suspension system that supports a pilot and attaches him to a glider.Heading: The direction towards which a glider points (this will be different fromactual flight direction in a cross wind).Headwind: A wind from the front or opposite the heading.Heat Capacity: The ratio of the amount of heat energy absorbed to the substance'stemperature increase.Heat Conductivity: Describes a material's ability to transfer heat via conduction.Hook In Weight: The total weight of the pilot and all equipment, excluding theparaglider.Hook Knife: A special knife used in emergencies to cut paraglider or tow lines.Horseshoe stall: A maneuver whereby one inner central A line of each side isheld until the canopy collapses in the form of a horseshoe.Infrared Radiation: Electromagnetic radiation with a wavelength between 3.5 and500 microns. Remote-sensing instruments work by measuring the radiation emit¬ted by objects in this spectral bandpass.Instability: An unstable air mass with a lapse rate greater than the dry adiabaticlapse rate (1oC/100m).

Isobars: Are curved lines on a weather map which connect points that have thesame atmospheric pressure.Kiting: Used more often as ground control.Laminar Air: Smooth, non-turbulent air.Land Breeze: A surface wind blowing from the land toward the sea during the night.Landing Gear: Your legs.Leading edge: The forwardmost part of a wing. The spar that forms this forward part.Lift: Uprising air used by the pilot to soar.Lift to drag ratio (l/d): A relation of the lift forces to the drag forces.Lock-out: An out-of-control swinging of the glider to one side with a subsequentnose dive while in tow.Log book: A book used to list flights and achievements.Lines: The rigging which connects the canopy to the harness.Maximum glide ratio: The best possible glide ratio for a given pilot and glidercombination.Micrometeorology: Is an offshoot of meteorology dealing with small-scale weatherpatterns.Minimum sink rate: The slowest descent rate possible with a given pilot andglider combination.Minimum sink speed: Usually achieved with the use of some braking.Millibar (mb): A common unit used for measuring atmospheric pressure. The aver¬age sea level pressure is approximately 1.013 mb, or 29.92 in. of mercury.Milking the Lines: Untangling the paraglider lines while on the ground.Msl: Abbreviation for mean sea level that indicates the height above the sea level.

NOTAM: Means NOtice To AirMen and contains information concerning the es¬tablishment or the change of condition of use of any aeronautical facility, service,procedure or hazard, the timely knowledge of which is essential for personnelconcerned with flight operations.

Orographic lift: Ascending air current produced by the prevailing wind when forcedto follow the mountain's contour towards the peak.

Parablend: To wrap your wing and/or lines in the propeller of a paramotor.Parachutal stall or Deep stall: This situation is invariably accidentally imposedon the pilot and is not a B-line stall, which is a controlled stall.

Parking or Parapark: When the wind speed matches the paraglider's airspeed.Pitch: Rotation about the lateral axis which is an axis from side to side. Amount ofnose up or nose down.PG: ParaGlider.Porosity: The measure of the amount of air that can pass through the wing's material.Polar curve: A graph or diagram where descent rate and flying speed are recorded.PPG: Powered ParaGlider.Preflight check: A careful inspection of the entire flying system before flight.Pressure Gradient: The rate of change of pressure over a horizontal distance.

Pressure Gradient Force: A force due to differences in pressure over some hori¬zontal distance. It acts from high to low pressure and is directly proportional to thepressure gradient.

Projected area: Projected span x average chord.Propeller: As in all aviation, this is nothing more than a spinning wing that pro¬vides thrust.

Race to goal: Starting point to arrival point (usually landing point).Radiation fog: Formed at night in light to moderate winds when the air is cooledby the ground which itself has been cooled by radiation. In the absence of mois¬ture or during strong wind conditions fog does not occur.

Rapid link (quick link): A small looped device used to attach risers to a harness.Reflex: An upward bending of the rear of an airfoil to prevent dives.Relative wind: Is produced by our wing during forward motion in the air. It has thesame axis but opposite direction to the flight path.Relative

Humidity: Relative Humidity expresses how much moisture is in the air, asa percentage of the total moisture the air can contain at the current temperature.Reverse launching: Involves turning around to face the wing and pulling it up,then turning back around to run for takeoff.Reserve parachute: A conventional parachute worn for use in case of emergency.Ribs: The vertical panels that separate cells in a canopy.Risers: Suspension lines. The lines that attach a harness to the canopy and holdthe canopies angle of attack.Roll: Rotation about the longitudinal axis, which is an axis going forward and back(Lifting or dropping a wing).Root: The center of the wing.Rotor: Turbulence as a result of being downwind of an obstacle.Saturated air: The air holding the largest possible amount of water vapor.Sea Breeze: A surface wind blowing from the sea towards the land, usually duringthe day.Sea smoke: Formed at sea due to the difference in temperature between seawaterand colder air. When water vapor evaporates it immediately cools and reachessaturation in the cold air.Sink: Falling air which makes the glider travel downward faster than normal.Slip: A falling to the inside of a turn due to insufficient push out.Sitter: A pilot who stops running early on take-off and sits in the harness challeng¬ing his luck.Soaring: Flight extended beyond the normal glide path of the glider.Span: The total width of a glider from tip to tip.Specific Heat: The amount of heat needed to warm 1 gram of a substance 1oC atsea-level pressure.Spiral dive: A dive consisting of continuous tight 360o turns.Spin: A violent rotation around one side of the wing.

Slope landing: Landing across a slope or inclination.Stability of the wing: Tendency of a glider to return to level flight.Stability of the atmosphere: When lower air masses are cooler or have the sametemperature as the upper air masses.

Stabilizer: A flap at the ends of a canopy to help hold its spread.Stall: A sudden loss of lift and increase in drag due to an excessive angle of attack.

Stalling turn: A turn with too much inside brake applied, resulting in a droppingback of the inside wing followed by a dive.

Steering lines: The control or brake lines used to steer a glider or change its speed.Stratosphere: A region of the atmosphere that lies between the troposphere andmesosphere. The lapse rate of the stratosphere is stable, meaning the tempera¬ture is constant with altitude or increases with altitude. The top of the stratosphereis marked by the stratopause and the bottom by the tropopause. The majority ofatmospheric ozone is formed in the stratosphere.Surface wind: Is the prevailing wind close to the surface of land and sea, and isaffected by friction.

Synoptic Scale Circulation: Weather phenomena whose spatial scale is similarin size to continents and oceans. Examples include fronts, cyclones and anticylones.Tailwind: A wind from the rear or in the direction of heading.Tandem: Two people flying together, the pilot and a passenger.

Tell-tale: A piece of yarn or cloth on the glider to tell wind direction at takeoff.

Thermal: A warm current of air rising from the sun-warmed earth that can be usedto gain altitude while in flight. A common source of low level turbulence.

Thermal Low: An area of low pressure created by large surface heating.Thermal Circulation: A local or regional circulation system that develops due topressure gradients created by differences in surface heating.Thunderstorm: A large convective cell that features violent weather in the form ofhigh winds, turbulence, lightning and hail.Tides: Periodic (occurring at regular intervals) variations on the surface of thewater level of oceans, bays, gulfs, and inlets. Tides are the result of the gravita¬tional attraction of the sun and the moon on the earth.Toggles: The hand recepticals or loops at the end of a steering line.Tow line: The line used to tow gliders with a vehicle.Top landing: Landing on a flat top surface of the mountain.

Top-Bottom: Flight in stable air.

Total weight (All Up Weight): The weight of the pilot and all equipment, includingthe wing.Trailing edge: The rearward part of a wing.Triangle: Competition race with at least 2 turn points.Triangle - FAI : Similar to above, but the turn points must obey rules determinedby the FAI (see www.fai.org).Trimmers: Configuration on the risers for altering the angle of attack

Troposphere: The lowest 10 to 20 km of the atmosphere. The top of the tropo¬sphere, the tropopause, is characterized by a rapid change in the lapse rate.

Tuck: Wing collapse.Turbulence: Gusts or swirls of air encountered in flight.

Turtle: To fall over backwards onto your paramotor while it's strapped to your back.

Upwind: A flight direction heading into the wind.UV: Ultraviolet radiation with a wavelength ranging between 0.2 and 0.4 microns.Urban Heat Island: Terminology used to describe the fact that city temperaturesare often warmer that the surrounding region.

Valley wind: Used to describe the existence of a wind in a valley, which differsfrom the general prevailing wind.

Vapor Pressure: The partial pressure exerted by water vapor.

Variometer: An instrument that displays your rate of descent or ascent.Velocity: A measurement of the speed and direction of motion.

Venturi effect: Wind increases velocity due to contricted flow and is named afterthe italian scientist that discovered it back in the 17th century.

Vortex: The swirling of air at the wing.V min: Minimum speed before the wing loses its capacity to stay airworthy.Achieved via brakes without the use of the speed bar or trimmers.

V max: Maximum speed via speed bar and trimmers.

V trim: Flying speed without the use of brakes, speed bar or trimmers.Wavelength: The distance between two consecutive crests, or troughs, of a wave.

Washout: A progressively different angle of attack from the center of the wing tothe wing tips.Weight (Total): The weight of the pilot carrying all his flying equipment includingthe wing.

Weight (Pilot): Body weight.Wonder wind: Is the mild lift produced by convergence of catabatic wind and thelast thermals of the day.Wind

Dummy: The pilot making the first flight of the day to test the prevailingconditions.Wind-gradient: Is the gradual reduction in wind speed as we approach the sur¬face due to the friction of the ground.

Windsock: A device used to show the direction of the wind and to some extentthe wind speed.

Wing loading: The weight-to-area ratio on an aircraft found by dividing the flyingweight of the pilot plus the glider by the total wing area.

Wingover: A maneuver which is in reality a climbing steep turn ending in a dive.Yaw: The motion of a wing whereby one side moves forward and the other movesbackwards. We call such rotation a change of heading.

Pocket Aviation :The guide to paragliding