Aerodynamics
| The study of the movement of a body through the air, such as a paraglider wing. |
| AGL | Above ground level. |
| ASL | Above sea 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(ASI). |
| Altimeter | An instrument for measuring altitude above a predetermined point. |
| Angle of Attack | The angle that the relative wind makes with the chord of the airfoil. |
| ASL | Above sea level. |
| Aspect Ratio | Ratio of the span to the chord. |
| Brakes | The controls of a paraglider that pull down the trailing edge. |
| Camber | The amount of curvature on the upper surface of an airfoil. |
| Canopy | The material or ‘sail’ of a paraglider that forms the airfoil of the wing. |
| Cells | The individual inflated units of a canopy between suspension lines. |
| Centre of Gravity | The point along the wing where all the weight is suspended. |
| Chord | Measurement of an airfoil from the leading edge to the trailing edge. |
| Coordinated turn | A turn at a steady rate at which a slip or stall does not occur. |
| Cross-ports | The holes in the ribs that allow the equalisation of pressure between cells. |
| Cross Wind | A wind angling across the normal launch or flight path. |
| Cross-Country | Flying beyond the normal landing field by using lift encountered along the way. |
| Deep Stall | An emergency situation whereby a glider descends with little or no forward speed ( also known as a parachutal stall). |
| Down Wind | Flying in the same direction as the wind (flying with a tailwind). |
| Drag | The energy losses on the glider due to the friction and mass of the air. |
| Dynamic Stall | A stall produced by pulling the brakes rapidly so that the pilot swings forward and worsens the stall. |
| End Cell Closure | A problem during inflation whereby the ends of the canopy do not open properly and may result in a collapse. |
| Flight Check | An inspection after inflation to check for tangled lines or end-cell closures. |
| 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. |
| Glide Ratio | The ratio of the distance travelled forward to the distance dropped. This is used interchangeably with L/D. |
| Ground Speed | The velocity of the glider over the ground. This is different from airspeed if any wind is present. |
| Gross Weight | Total weight of the glider and the heaviest allowed payload (pilot). |
| Harness | A suspension system that supports a pilot and attaches him to the glider. |
| Heading | The direction a glider points (this will be different from actual flight direction in a cross wind). |
| Headwind | A wind from the front or opposite the heading. |
| Horseshoe Stall | A manoeuvre whereby full brakes are held until the canopy collapses in the shape of a horseshoe. |
| Leading Edge | The forward most part of the wing. The span that forms the the forward part. |
| Lift | Uprising air used by the pilot to soar. |
| Lift to Drag Ratio(L/D) | A comparison of the lift forces to the drag forces. (see glide ratio). |
| Log Book | A book used to list flights and achievements. |
| Maximum Glide Ratio | The best possible glide ratio for a given pilot and glider combination. |
| Minimum Sink Rate | The slowest possible descent rate possible with a given pilot and glider combination. |
| MSL | Mean Sea Level - for indicating height above the average sea level. |
| Pitch | Amount of nose up or nose down. Movement about a lateral axis. Backward and forward motion of the glider. |
| Preflight Check | A careful inspection of the entire flying system before inflation. |
| Rapid Link (Quick Link) Karabiners | 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 | The wind relative to the glider in flight. Since the glider is always moving with respect to the air around it, the relative wind is different from the wind on the ground. |
| Ribs | The vertical panels that separate cells in a canopy. |
| Risers | The webbing that connects the suspension lines and connects to the harness. There are two sets of risers and each riser is generally divided into As, Bs, Cs & Ds, from the front to the back of the canopy. |
| Roll | The lifting and dropping of the wing tips about a central axis. It is a side to side motion as opposed to a backwards/forwards motion associated with pitch. |
| Rotor | An organised swirl of air behind a cliff face, mountain, building, tree or other obstacle. |
| Sink | Falling air which makes the glider travel downwards faster than normal. |
| Soaring | Flight extended beyond the normal glide path of the glider. |
| Span | The total width of the glider from tip to tip. |
| Stability | Tendency for the glider to return to level flight from any altitude or bank. |
| Stabilizer | A flap or series of cells 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 dropping back of the inside wing followed by a dive. |
| Steering Lines | The control or brake lines used to steer a glider or chnge its speed. |
| Suspension Lines | The lines that attach the risers to the canopy and hold the canopy's angle of attack. |
| Tailwind | A wind from the rear or in the direction of heading. |
| Tandem | Flying with two persons on a glider. |
| Tell-Tale | A piece of yarn or cloth on the glider top tell wind direction at take-off. |
| Thermal | A mass of warm rising air providing lift |
| Thunderstorm | A large convective cell that features violent weather in the form of high winds, turbulence, lightning and hail. |
| Toggles | The hand receptacles or loops at the end of a steering (brake) line. |
| Tow Line | The line used to tow gliders with a vehicle. |
| Trailing Edge | The rearward part of the wing. |
| Turbulence | Gusts or swirls of air encounterred in flight. |
| Upwind | A flight direction heading into the wind. |
| Variometer | A device that indicates when the glider is rising or sinking |
| Velocity | A measurement of the speed and direction of motion. |
| Vortex (Tip Vortices) | The swirling of air at the tips of a glider. |
| Wind Gradient | Slowing of the wind as the ground is approached. |
| Wind Sock | A cloth tube mounted on a pole to indicate wind direction. |
| Wing Loading | The weight-to-area ratio on an aircraft found by dividing the flying weight of the pilot plus the glider by the total sail area. |
| Yaw | The motion of a wing whereby one side moves forward and the other moves back . |
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