Guides

Field reference · 3 sports

Paragliding Knowledge Base

Aerodynamics, weather theory, forecast reading, active flying, launch & landing fundamentals.

📐 Aerodynamics & Forces

The Four Forces

Lift — generated by air deflected over the curved upper surface of the wing creating low-pressure above.
Drag — air resistance opposing forward movement. Parasite drag (lines, harness, pilot) + induced drag (byproduct of lift).
Weight (Gravity) — acts straight down through center of mass. Constant force.
Thrust — paragliders have none. Altitude (potential energy) is traded for speed (kinetic energy). A glider must always descend relative to its surrounding air.

Angle of Attack (AoA)

AoA = angle between the wing's chord line and the relative airflow (relative wind).
Increasing AoA (more brake) → more lift AND more drag, up to a critical point.
Beyond the critical AoA → airflow separates from the upper surface → stall. Lift drops instantly, wing collapses behind you.
At trim (hands up) the wing is at its design AoA for best efficiency.
Speed bar / accelerator decreases AoA → faster flight, lower lift, lower drag.
Stall speed is NOT fixed — it changes with wing loading, moisture, altitude, bank angle, and G-loading.

Glide Ratio & Polar Curve

Glide ratio = horizontal distance ÷ vertical distance. A 9:1 wing travels 9m forward for every 1m it descends in still air.
Best glide is at trim speed (hands up). Adding brake reduces glide. Adding speed bar eventually reduces glide too.
Min sink = slowest descent rate (~1.0–1.2 m/s for modern wings). Slower than trim. Useful for thermaling, NOT for penetrating.
The polar curve plots airspeed (x) vs. sink rate (y). The tangent line from the origin to the curve gives best-glide speed.
Speed-to-fly theory: in headwind, fly faster (shift origin right). In tailwind, fly slower. In sink, fly faster. In lift, slow down.

Airspeed vs. Groundspeed

Airspeed = speed of wing through the air mass. Determines flight characteristics (stall, lift, control).
Groundspeed = airspeed ± wind component. What you see relative to the terrain.
Headwind: ground speed = airspeed − wind → reduced glide ratio over ground.
Tailwind: ground speed = airspeed + wind → improved glide ratio over ground.
Your wing does NOT know groundspeed. It only feels airspeed. A wing at trim in 30 km/h wind feels exactly the same as in zero wind.
In a tailwind, do NOT add brake to "slow down." You will only increase AoA toward stall while groundspeed causes the optical illusion of being fast.

Wing Loading

Wing loading = total all-up weight ÷ projected wing area (kg/m²).
Higher loading → faster trim speed, higher stall speed, better penetration, sharper handling, less susceptible to collapses in turbulence, but more dynamic when collapses DO happen.
Lower loading → slower flight, lower stall speed, easier handling, but more vulnerable to collapses and more affected by turbulence.
Always fly within the manufacturer's certified weight range for your wing size.

🌍 Weather Theory

Atmospheric Stability

Stable atmosphere: displaced air parcel cools faster than its surroundings → sinks back down. Smooth, layered air. Inversions. Haze.
Unstable atmosphere: displaced air parcel stays warmer than surroundings → keeps rising. Cumulus clouds, thermals, turbulence.
Conditionally unstable: stable for dry air, but unstable once moisture condenses (releases latent heat). Most common real-world state.
Environmental lapse rate (ELR): actual temp decrease with altitude. Standard = ~6.5°C/1000m. Compare to DALR (9.8°C/km) and SALR (~5°C/km).
If ELR > DALR → absolutely unstable. If ELR < SALR → absolutely stable.

Pressure Systems

High pressure = descending air, clockwise rotation (NH). Generally stable, sunny, inversions.
Low pressure = ascending air, counter-clockwise rotation (NH). Unstable, clouds, precipitation.
Isobars close together = steep pressure gradient = strong wind. Spaced apart = light wind.
Wind flows roughly along isobars (geostrophic balance) but surface friction turns it ~15–30° toward low pressure.
Standard pressure = 1013.25 hPa / 29.92 inHg.

Fronts

Cold front: cold air undercuts warm air. Steep boundary. Short, intense weather. Rapid clearing. Strong wind shifts.
Warm front: warm air overrides cold air. Gradual slope. Prolonged cloud cover, steady precipitation, fog.
Stationary front: neither advancing. Persistent cloud/rain along boundary.
Occluded front: cold front catches warm front. Complex — usually means deteriorating conditions.
Pre-frontal conditions can be excellent for flying (strong thermals, wind acceleration). Post-frontal cold air can produce epic days with clear skies.

Inversions

A layer where temperature INCREASES with altitude instead of decreasing. Acts as a "lid" on convection.
Common types: radiation inversion (overnight surface cooling), subsidence inversion (from high-pressure descent).
Thermals punch through weak inversions. Strong inversions cap cloudbase and trap haze/smoke below.
When you see a flat, uniform haze layer — that's an inversion. Thermal tops will be right at that layer.

Adiabatic Processes

DALR (Dry Adiabatic Lapse Rate): 9.8°C per 1000m (~3°C/1000ft). Rate at which unsaturated air cools when rising.
SALR (Saturated): ~5–6°C/1000m. Slower cooling because condensation releases latent heat.
Dew point: temp at which air becomes saturated. Spread between temp & dew point narrows ~2.5°C/1000ft → gives cloudbase estimate.
Cloudbase estimate: (Surface temp − Dew point) ÷ 2.5 × 1000 = cloudbase AGL in ft. Or × 400 for meters.

📊 Reading Forecasts

Key Metrics to Look For

Surface wind — direction & speed at your launch/landing elevation. Cross-reference multiple models.
Winds aloft — wind speed and direction at 3k, 6k, 9k, 12k ft. Strong winds aloft may cascade down. Shear between layers = turbulence.
Thermal trigger temp — the surface temp at which thermals will start. Compare against the hourly forecast to estimate thermal onset.
Cloudbase / Condensation level — use dew point spread. Low cloudbase = limited thermal height.
CAPE (Convective Available Potential Energy) — higher CAPE = stronger thermals. >1000 J/kg → risk of overdevelopment/thunderstorms.
CIN (Convective Inhibition) — energy needed to break through inversions. High CIN = thermals may not trigger.
LCL (Lifted Condensation Level) — altitude at which air becomes saturated → cloudbase.
Skew-T diagram — the gold standard. Shows temp and dew point vs. altitude. Steep ELR = unstable. Inversions visible as temp kinks. Moisture visible from temp/dew point gap.

Forecast Tools & Sources

Skew-T / Soundings: weather.uwyo.edu, RASP, XCSkies. Read ELR slope, inversions, moisture layers.
Wind data: Windgram (RASP), Windy.com, XCSkies, NOAA winds aloft text products (winds aloft by station).
Surface weather: weather.gov (METAR/TAF), weatherunderground.com (personal stations), Holfuy / Tempest / iMeteos (on-site).
Thermal prediction: RASP (blipmap), XCSkies, paraglidable.com — show thermal height, strength, cloud cover.
Satellite/radar: goes2.com (visible + IR satellite), radar.weather.gov, Windy radar layer.
Key: cross-reference multiple sources. No single model is always right. Trust on-site observations above all.

Interpreting Soundings (Skew-T)

Temp line (right) far from dew point (left) = dry air. Close together = clouds/moisture at that level.
ELR steeper than DALR (9.8°C/km guideline on chart) at a layer = unstable at that layer.
Inversions: temp line bends right (warming with altitude). Thermals stop there unless very strong.
Wind barbs on right side show direction + speed at each altitude. Look for shear (rapid direction change).
Surface temp vs. trigger temp: if forecast max exceeds trigger temp, thermals will fire. If not, likely a glass-off day.

The Morning Checklist

1) Synoptic overview — fronts? Pressure systems? Jet stream position?
2) Surface wind forecast through the day (pick launch/landing windows).
3) Winds aloft — shear layers? Valley vs. ridge wind direction?
4) Thermal prediction — trigger time? Expected strength? Overdevelopment risk?
5) Cloudbase / ceilings. Airspace considerations at predicted cloudbase.
6) Satellite loop — what is actually happening vs. what models predicted?

☁️ Weather — In the Air

Cloud Reading

Cu (cumulus): healthy convection markers. Small, flat-based, white = ideal. Dark flat base = strong thermal beneath.
Growing / towering Cu: convection intensifying. If taller than wide → may develop into Cb.
Wispy / ragged Cu: dying thermals. Indicates cycle is ending in that area.
Cloud streets: aligned Cu in rows parallel to wind. Fly along the street for continuous lift between clouds.
Lenticulars: smooth lens clouds = mountain wave. Very strong winds aloft. Generally avoid unless experienced in wave.
Cirrus increasing / thickening: front approaching. 12–24 hrs out.
Cumulus spreading into overcast: overdevelopment. Thermal quality deteriorates. Get down if anvils appear.

What to Monitor In-Flight

Wind speed & direction changes — compare different altitudes. Sudden direction shift = convergence or front passage.
Thermal strength & regularity — weakening thermals late day = landing window approaching.
Cloud development pace — Cu cycling faster = day is over-developing. Watch for early Cb growth.
Visibility / haze line — haze trapped under inversion tells you stability is increasing below.
Ground indicators — smoke, dust, flags, water surface ripple. Check wind direction at landing field.
Other pilots' height — collective intel on thermal strength & position.

Thermal Indicators on the Ground

Dark / dry fields (parking lots, plowed earth, rock faces) = heat sources.
Green fields, water, forest = cool, often produce sink.
Boundaries between hot & cool surfaces are prime trigger zones.
Birds circling = thermal. Dust devils = strong thermal releasing.
Smoke lean / wind streamers = wind direction and turbulence intensity.

Dangerous Conditions to Recognize

Gust front: sudden strong wind shift ahead of an approaching storm. Can arrive 20+ km ahead of visible rain.
Overdevelopment: Cu growing unchecked → Cb. Once anvils spread, violent downdrafts, hail, lightning possible.
Valley winds overpowering thermals: late afternoon, mountain wind can overwhelm thermal cycles. Rapid conditions change.
Foehn / Chinook: warm, dry wind descending on lee side of mountains. Extremely turbulent, strong, and can go from calm to 60+ km/h.
Rotor: turbulent roll behind ridges. Violent sink, deflations, loss of control. Stay on the windward side.
Cloud suck: strong lift under active Cu. If climbing rapidly and can't escape with full speedbar + ears → prepare for emergency: big ears + speedbar, B-stall, or spiral. Do NOT enter cloud.

💨 Wind Systems

Valley Wind Cycles

Anabatic (upslope): sun heats slopes → air flows uphill. Starts on sun-facing slopes. Strongest mid-afternoon.
Katabatic (downslope): slopes cool after shade/sunset → air flows downhill. Starts in shaded gullies. Strongest near dawn.
Valley wind: cumulative effect of anabatic on all slopes → warm air rising → draws air UP the valley floor during the day.
Mountain wind: reverse at night — cool air drains down the valley. Weakens or reverses the valley breeze.
Transition periods (morning switch, evening switch) can produce unpredictable lulls, direction changes, and turbulence.

Sea Breeze

Land heats faster than water → thermal low over land → onshore wind develops.
Typically starts late morning, peaks in afternoon, dies at sunset.
Sea breeze front = convergence zone where sea breeze meets the existing wind. Can produce strong thermals and turbulence along the front.
Can penetrate 30–100+ km inland on hot days.

Venturi & Compression

Air accelerates when forced through a narrow gap (between peaks, along ridges, through passes).
Expect significantly stronger winds in terrain constrictions even if ambient wind is light.
Wind accelerates over ridge tops (compression zone). Wind at the top of a ridge can be 2–3× stronger than at the base.

Lee-Side Effects

Rotor: turbulent vortex on the downwind side of any obstacle. Size depends on obstacle + wind speed.
Lee-side sink: descending air behind ridges. Can exceed your climb rate.
Mountain wave: smooth, powerful lift extending tens of km downwind. Marked by lenticulars. Altitude gains can be enormous but turbulence in the rotor layer below is extreme.
Rule of thumb: rotor extends ~10× the obstacle height downwind. Avoid flying within rotor zones.

🎮 Active Flying & Wing Control

Pitch Control

Wing surges forward (pitch down): apply progressive brake to check it. Don't slam brakes. Match energy.
Wing falls back (pitch up): release brake, let wing accelerate forward. Feed energy back with hands up.
In turbulence: anticipate pitch oscillations. Damp early, damp lightly. Over-correction causes PIO (Pilot-Induced Oscillation).
Always fly with a few cm of brake pressure ("active hands") — not hands-off, not deep brake. ~10–15% toggle.

Roll Control

Roll oscillation (swinging side to side): apply symmetric brake on BOTH sides. Hold until stable. DO NOT alternately correct.
Weight-shift is the primary roll input. Lean into the direction you want to go. Look where you're going.
Over-banking in a turn → apply outside brake and shift weight outside.

Collapses

Asymmetric collapse: wing folds on one side. Weight-shift toward the OPEN side. Brake on the open side to stay on course. The folded side usually re-inflates on its own. If it doesn't: short, decisive pump on the collapsed side.
Frontal collapse: leading edge tucks under. Hands up immediately to let the wing reopen. Do NOT brake during a frontal — you'll deepen the stall.
Full stall / parachutal: wing is flying but barely. Both brakes too deep. Slowly raise hands symmetrically to restore airspeed.
After ANY collapse: check heading, check altitude, check traffic. Assess before making further inputs.
Higher EN-rated wings (D, CEN) require faster, more precise responses. Collapse severity increases with wing loading and turbulence intensity.

Speed System (Speedbar)

Pushes A-risers forward → decreases AoA → increases speed, decreases lift.
Use for headwind penetration, escaping sink, or gaining speed-to-fly efficiency.
In turbulence: use speedbar cautiously or not at all. Reduced AoA means frontal collapses are more likely.
Speedbar + ears = fastest descent without spiraling. Good for getting below cloud suck or escaping lifting air.

Big Ears

Pull outermost A-lines to fold wingtips in. Sink rate increases to ~3–4 m/s.
Fly on speedbar with ears for faster descent (~4–5 m/s).
Release ears by short brake pumps on the collapsed tips. Some wings reopen on their own when you let go.
Maintain directional control with weight-shift while ears are in. No brake input on collapsed tips.

Spiral Dive

Deep, committed turn with high bank angle + inside brake. Sink rates can exceed 10–15 m/s.
To exit: slowly release inside brake, add outside brake if needed, weight-shift to outside.
Some wings auto-spiral (lock in). Practice at altitude under instruction first.
G-forces are high. Tunnel vision / G-LOC is real. Know your limits.

B-Stall

Pull both B-risers down symmetrically → wing deforms, lift drops, rapid descent.
Sink rate ~6–8 m/s. Wing is very stable in B-stall.
To exit: release B's symmetrically. Wing re-inflates and dives forward. Be ready to manage surge.
Useful for descending rapidly while staying in roughly one position (less drift than spiral).

🚀 Launch

Forward Launch

Face downhill. Wing laid out in clean "U" or wall behind you.
A-risers in hands or crooks of elbows. Toggles in hands. Run smoothly, building speed.
As wing comes overhead: brief look up/back to check lines — then commit forward. Do NOT slow down to look.
Best for: light wind, no wind, unfamiliar terrain where you need to see your run-out.

Reverse Launch

Face the wing, risers crossed. Build a wall, control position, inflate with A-risers.
Visually inspect: lines clear, no cravats, cells open, wing symmetric.
Commit to turn and run when you are satisfied the wing is clean overhead.
Best for: moderate-strong wind. Lets you see the wing fully before committing.

Launch Assessment

Wind direction: ideally within 30° of straight up the slope. Cross-wind launches are advanced.
Wind speed: too little = long run, too much = risk of being lifted before ready.
Slope gradient: steep = less running but faster events. Shallow = more commit needed.
Obstacles: rocks, bushes, fences below launch. Know your abort plan.
If you are not confident in conditions → do NOT launch. Pack up and wait or walk down.

Pre-Flight Check

Helmet buckled. Harness leg straps, chest strap, shoulder buckles — ALL connected. No partial hookup.
Lines from risers to canopy: clear of tangles, knots, grass. Pull brakes gently to check trailing edge.
Reserve pin/handle secure. Speed system functional. Radio on.
Airspace overhead: clear of other pilots.

🎯 Landing

Approach Planning

Set up a landing pattern: downwind leg → base leg → final approach (into the wind).
Always land into the wind. Groundspeed is minimized → softest touchdown. Wind direction at ground level may differ from aloft.
Look at wind indicators (flags, smoke, windsock, grass, other pilots' streamers) to confirm ground-level wind.
Have a primary and secondary landing target. Decide early which you're using.
Avoid the "S-turn approach" close to the ground — it's easy to misjudge altitude and stall the wing in a low turn.

Landing Technique

On final approach: take your feet out of the harness stirrup, stand up in the harness, hands at shoulder height.
Flare timing is everything. Begin flare ~2m above ground. Progressive symmetric brake to full arm extension below hip.
Flare too early: wing stalls with altitude remaining → you drop. Flare too late: fast ground contact.
In no wind: flare needs to be aggressive and well-timed. You arrive with higher groundspeed.
In strong wind: less flare needed. Wing may try to lift you back up — step forward and kill the wing with brakes after touchdown.

Landing Hazards

Downwind landing: high groundspeed + no flare authority = hard impact. Avoid at almost all costs.
Lee-side rotor near LZ: if the LZ is behind a tree line, ridge, or building, expect turbulence and sink on approach.
Gradient wind: wind can be 2× stronger 20m up than at ground level. Causes sudden sink on approach.
Other traffic: check for pilots on approach. Right-of-way: lower pilot has priority. Never fly under another pilot.
Wires / obstacles: scan approach path for power lines, fences, poles. They are nearly invisible from the air.

Top Landing

Approach from the side or at a 45° angle. Never fly behind the ridge (rotor zone) to set up.
Match speed to terrain. Arrive with minimum altitude and minimum groundspeed into the wind.
Be prepared to abort and fly out if anything feels wrong — you're very close to the ridge with low altitude, low margin.
Kill the wing immediately after touchdown to prevent being dragged in gusts.

⚖️ Rules of the Air

Right-of-Way Rules

Ridge soaring: pilot with ridge on their RIGHT has right-of-way. Oncoming pilot turns away from the ridge.
In thermals: first pilot in the thermal sets the turn direction. All others must turn the same direction.
Overtaking: the overtaking pilot must keep clear. Pass to the ridge side if soaring.
Landing: lower pilot has priority. Do not fly under another pilot on approach.
Head-on: both turn right.
Launching: launching pilot does NOT have right-of-way. Yield to pilots already in the air.

General Safety

Maintain visual separation from all other traffic at all times.
Don't thermal directly below another pilot — their collapse could fall on you.
When landing in a designated LZ, join the standard pattern — don't cut in.
Ground handling near an active launch: keep your wing deflated when others are launching.
Right-of-way rules are important, but always look out for pilots who might not know them.

🛡️ Safety & Decision-Making

Personal Minima

Set clear go/no-go limits BEFORE you arrive at launch: max wind, max gust factor, min visibility, min cloudbase.
Your minima should be tighter than what the wing can handle. Expand gradually with proven experience.
If conditions exceed your minima → walk down. No flight is worth an accident.
Fatigue, stress, illness, dehydration, time pressure all lower your effective skill level. Adjust minima accordingly.

The IMSAFE Checklist

I — Illness? M — Medication? S — Stress? A — Alcohol / drugs (last 24hrs)?
F — Fatigue? E — Eating / hydration?
If any answer is concerning → don't fly, or fly conservatively.

Hazardous Attitudes

Anti-authority: "Rules don't apply to me."
Impulsivity: "Do something — quick!" (without thinking).
Invulnerability: "It won't happen to me."
Macho: "I can handle it." (when you can't)
Resignation: "What's the use?" (giving up on safety measures).
Recognize these in yourself. Every pilot has them occasionally. The skill is catching them.

Reserve Parachute

Check reserve handle/pins on every pre-flight.
Have reserve repacked every 6 months (min annually). Practice handle-location drills in the harness.
Deploy into clear air, away from the main wing. After deployment, disable the glider by pulling a riser to prevent downplaning.
Minimum useful deployment altitude: ~100–150m AGL. Below that, focus on managing the main wing.