Basic Paraglider Questions Answered

Introduction

Let's demystify some of the most basic questions people have about paragliders!

I often get asked some of these basic questions, so it makes sense to answer them on the internet as well.

Questions

What is a paraglider?

A paraglider is a non-rigid, self-inflatable, airfoil. It is made of lines and fabric, sewn together to form a canopy that allows pilots to glide through the air.

This aircraft was invented by mountaineers, who wanted a quick way to get down from the summits they had climbed. The original inspiration were steerable parachutes.

A paraglider is also one of the most fun and addictive toys a person can get. The feeling of freedom it provides is similar to sailing.

The mobility of a paraglider is not quite the same as sailing. It isn't always possible to travel in any direction the pilot wishes.

Like sailing, and surfing, paragliding is very dependent on the weather. The weather determines if it will be possible to fly.

How does a paraglider work?

The paraglider is composed of the wing as well as the harness with the pilot inside it. The weight of the pilot brings stability to the wing while in flight.

The leading edge of a paraglider has openings, these are ram-air intakes. The wind pushes into the glider and causes an increase in the glider’s internal pressure. This inflates the paraglider.

The paraglider’s airfoil is asymmetrical. The upper surface has more curvature, which increases the distance traveled by air. This causes another difference in pressure between the air at the upper and lower surfaces of the glider, known as Bernoulli's principle.

On a paraglider Bernoulli’s principle works very lightly to lift the paraglider, but it does make a difference in glide-ratio.

To go up paragliders need to find currents of air that are moving upwards. These are usually thermals, but they can also be ridge lift, wave lift or convergence.

Paragliders are fairly unique in how the sport is exercised. No other aircraft is as simple to store and transport.

Paragliders are also able to climb thermals much like birds do in tight 360 turns. It is common for pilots to share a thermal with birds.

A paraglider can be packed into a rucksack. This allows a pilot to just hop on a train or hitch a ride.

Pilots will often hike up a mountain to a clearing with their gliders on their backs. The takeoff is usually done from a location which is near to a thermal trigger.

A typical rucksack will weigh around ten or twenty kilos. This depends on the type of glider and size of the pilot.

Water is often added as ballast in order to keep the glider at the pilot’s preferred performance. Water is handy because it can be safely discarded or used as drink-water in the case of a long walk-out.

How does a paraglider turn?

To turn pilots make use of brake toggles or weightshift, or both. An external force such as a thermal or gust can also cause the glider to turn.

Paragliders mostly turn in order to stay in lift. Usually pilots go where the lift is in order to fly long distances.

Most commonly a turn is performed with brake input. The paraglider has two brake toggles. Each toggle slows down one side of the canopy. By slowing down one side of the canopy, the other flies faster and a turn is performed.

Brake toggles cause a slight inefficiency in glide as the paraglider’s aerodynamic profile is changed.

Weight-shift is another way of turning that can be combined with brake input to turn the glider more efficiently.

Slower than using the brake toggle, but more efficient, weight-shift alone can turn a paraglider.

There is a lot of discussion about why weight-shift actually turns the glider. Physicists will likely quarrel over how the centripetal force is generated for decades.

Suffice it to say that turning a glider efficiently in light lift will take many hours of training; and turning the paraglider is only one of the axes a paraglider has.

Progression in paragliding will mean understanding how the different rotation axes work, what effects each input has on the glider, and finally getting the finesse and timing for controlling the glider with minimal input.

Paragliders are capable of turning quite fast. Spirals are 360 degree turns with a higher than usual bank.

Spirals cause the paraglider to lose height very quickly. The centrifugal force increases the g-force experienced by the pilot.

Spirals are classified by their bank. The bank is the angle the wing makes in relation to the horizon. The angle starts at 90 degrees with the wing vertical, obscuring some of the pilot’s view of the horizon. A deep-spiral, or nose-down spiral, is the fastest descending spiral, and its angle is effectively zero.

The descent speed of a paraglider in a deep-spiral is around 20 meters per second, and the g-forces may go as high as 4G. Paragliders are built to withstand 8G or higher.

How does a paraglider land?

Paragliders flare on landing. This changes the vertical and horizontal velocity of the glider. When timed correctly the pilot touches down very softly.

A pilot’s first flights are supposed to get the flare dialed in. Small hills are used to exercise both takeoff and landing.

A flare is initiated by pulling both brake toggles down symmetrically. This changes the pitch of the glider.

Braking causes the trailing edge of the glider to deform. The trailing edge bends down. This increases the drag on the wing, and the wing falls backwards.

This shift in the canopy’s position means that the pilot is lifted vertically momentarily. If the brake toggles were to be released, the pilot would sink and move backwards in relation to the canopy. The canopy tries to stay in equilibrium. In this configuration it will shoot up and forward, quickly pass overhead the pilot, and start slowing down until it starts flying back again in relation to the pilot, forming a “pitch-pendulum.”

A typical landing flare is not supposed to induce a full pendulum swing. Touching down should happen just before the glider has reached its furthest back position in relation to the pilot.

If a pilot does not flare, the pilot may not get hurt and merely stumble. However the landing is a lot softer and safer with a flare.

Landings should also be performed up-wind. The paraglider should be pointing into the wind when landing.

Landing up-wind has the benefit of slowing the paraglider’s speed relative to the ground.

Paragliders’ speed relative to the air around it is constant. Though the air itself is moving at some speed.

The most dangerous landing a pilot could do is heading down-wind.

Let’s say an average paraglider’s speed through the air is 35km/h, and let’s say the wind on this day is 10km/h. If the pilot were land pointing into the wind, his ground speed would be 25km/h.

With a flare the pilot can cut the speed down a lot further, but 25km/h isn’t very likely to be fatal.

On the other hand when landing down-wind the paraglider would be moving at 45km/h relative to the ground. At this speed, a failed landing is more likely to cause a serious injury.

How does a paraglider stay in the air?

Paragliders stay up in the air by using currents of rising air. Thermals, ridge-lift, wave-lift, and convergence are sources of natural lift which are used in freeflight.

Thermals are by far the most common way of getting any real distance traveled. These are usually the only form of lift available over flat terrain.

Pilots will obsess about finding the day with the best lapse rate for going cross country, since these are the days on which much praise and personal satisfaction can be earned.

Learning some meteorology just for the sake of knowing the days with the best thermic conditions is very common among pilots.

Besides knowing about a good day, there is also the knowledge of where these thermals are likely to sprout from on the terrain.

Pilots will have to learn to find thermals. They do so by exploring the air, noticing the terrain features, the wind direction, or noticing any other visual cues such as newly forming clouds, flying birds or insects.

Ridge lift can only take a pilot so far. To fly many kilometers in mountainous terrain pilots must make valley crossings. These valley crossings require the type of height that only thermals provide.

Rookie pilots will often start learning to fly on ridge lift. Ridge-soaring is usually simpler to fly than thermalling, and it is also less taxing on the nerves.

Ridge lift is soft and gentle on the coast. Laminar wind comes from the sea, it hits a coastal ridge and goes up.

While ridge-soaring a pilot does not need to worry about where to find lift. The pilot is in lift almost constantly, which can mean time to relax, plan, eat, take a selfie, among other things.

The ridge does not have to be as high as it needs to be wide. There are probably plenty of unflown ridges out there, unflown possibly only due to a lack of pilots.

If you are wondering about whether your local ridge is soarable, it probably is. Even dunes are soarable and make for a great place to learn and practice.

Wave lift is a pretty rare experience for paragliding pilots. It is not very well known. It is also possible that paragliding equipment itself may fly too poorly to even reach the wave effect.

Wave lift forms by meteorological wind being forced up a mountain and then back down again. The down part is important, as a plateau on top will not form a wave.

In contrast to ridge soaring, the wave is not in front of the mountain, but several hundreds or thousands of meters behind it.

A Wave forms because of the pressure difference, and rotor caused by the interaction of the wind with the terrain.

Given specific topology and the specific meteorological conditions of the day (since wave-lift does not form exactly the same every day) at some distance behind the mountain, the wind will have compressed down enough the pressure difference of the air above it will actually cause the air to go back up. This forms the wave, in a shape similar to the mountain that caused it.

There may also be multiple waves repeating further down-wind of the mountain. Multiple mountains can also aggravate the wave effect, or even cancel it out.

Convergence forms when two currents of air meet in opposite directions. The air has nowhere else to go so it rises.

Pilots look for convergence that creates a bridge allowing them access to places they normally cannot.

Convergence is a spectacular form of lift to experience, they are much rarer to find than thermals.

How long can paragliders stay in the air?

Paragliders depend on the weather conditions to stay aloft. So as long as there is an up-draft to re-fuel paragliders with height pilots can stay flying.

Thermals will shut down after the sun stops heating the surface. At night there are no thermals.

A sailplane record was set in Hawaii, clocking at 70 hours. It would be likely possible for a paraglider to perform a similar flight, using ridge-lift at night.

These flights are not common and seldomly attempted. Pilots may suffer from sleep deprivation and could be at risk of crashing should they fall asleep.

On the more common type of long-lasting flights, pilots are attempting to break distance records, or their own personal best. These flights last up to 12 hours near the equator. Long-distance flight records have a requirement that pilots must also land before sunset for the record to be ratified.

How far can a paraglider fly?

Hundreds of miles. The latest world record is over 600km. It was set in Texas by Sebastien Kayrouz. Prior to this flight the record had been broken repeatedly in the Northeast of Brazil for many years.

In order to fly long distances pilots must get used to flying for many hours. Pilots must eat and drink while flying, as well as urinate in the air.

It is very common for pilots to go somewhere other than their home site to perform their first 100km, or their 200km, and certainly the 300km mark.

Conditions are better at certain locations in the world, and conditions make a big difference in being able to achieve long flights.

Can you paraglide with no wind?

It is possible to paraglide with no wind. Though an experienced pilot will remind you “there is no such thing as no wind.”

In no wind days, if the sun is out, local winds will still form, these are the result of thermals forming.

No wind days usually mean paragliders cannot travel as fast when going cross-country.

At high mountain ranges there are typical “no wind” conditions. The meteorological wind will stay over the peaks of the mountains, though thermals will still cause valley winds.

With very light wind the pilot may have to launch using the forward launch, also known as the alpine launch. The alpine launch is usually the first launch taught to students.

Typical cross-country flights on no-wind days in the flats are FAI triangles. FAI triangles are flights where the three points of the triangle are supposed to be as close to an equilateral triangle as possible.

These out-and-return flights are handy because pilots land where they started from, without the need of a retrieve or public transport to get back home.

How high can paragliders go?

Paragliders will go as high as cumulus clouds go. The record is different in every country. High mountain ranges usually mean a higher ceiling.

Long-distance flights are typically flown at around 1000 to 2000 meters above ground. Local flights are usually performed under 1000 meters above ground.

One paraglider, Ewa Wisnierskam, was accidentally taken to a height of 9946 meters above sea level, while inside a storm cloud known as a Cumulus Nimbus.

An intentional record that was not flown inside a cloud was recently set by Antoine Girard in the Karakoram range. Antoine flew to 8407 meters above sea level, without oxygen, under a glorious blue sky.

Usually pilots will not go past 5000 meters above sea level and do not suffer from hypoxia. Some days do allow for flying higher than the range where hypoxia starts to occur and pilots may carry oxygen. Hypoxia starts to happen between 5000 and 6000 meters above sea level.

The more common issue with flying in very high altitudes is the cold. Especially during spring, pilots can be met with freezing temperatures. High mountain ranges will also often take pilots to extreme cold even during summer.

Flying as high as possible is sought after by many pilots. Altitude is the fuel that is spent “on glide”. Pilots hop from thermal to thermal, usually heading towards a fresh forming cumulus cloud they see in the direction of their intended destination.

Do paragliders have parachutes?

Paragliders do have reserve parachute systems. Reserve parachutes save lives. It is highly recommended to fly with one or two.

Parachutes require more than 50 meters to open and stop the free fall.

Pilots often take too long to decide whether to deploy their reserve parachute. Often this is because the pilot may be trying to resolve the issue with the glider.

There are many reasons why a pilot may need to throw their reserve parachute. Though mainly it is the case that the pilot has lost control over the glider and is in some high speed vertical descent, which could result in serious injury or death.

It isn't a super common thing to need to throw the reserve. Many pilots have never even seen the color of their reserve chutes. Though when needed, it is best to be prepared to deal with these emergency situations.

Reserves have different models, brands, and sizes.

The most common reserve parachute is still the round parachute. This tried and true parachute is very simple to deploy and pack.

The square or triangular type of parachutes are said to eliminate some of the pendulum effect the round parachute can suffer from. They are usually harder to pack.

There are also steerable parachutes. The rogalo style parachute was designed in the 60s and even used by NASA in the space program. A few brands have developed steerable triangular and square parachutes, as well as a base-jump style parachute with a cut-away release system designed for acrobatics pilots.

Conclusion

I’d like to mention that while paragliding is a risky sport, it is generally safe. It is certainly quite harmless on the training hill.

It is during progression that the risk envelope starts shifting. Rookie pilots generally have little idea about the dangers that exist in paragliding. This is why it is important to fly with other pilots. The terrain can offer several hazards, and more experienced pilots will know about them.

Paragliding is very diverse and entertaining. The sport is both challenging in terms of skill and knowledge. The people in the sport are about as varied as the colors of their gliders, and usually very welcoming to new pilots.

Trial tandems and first lessons are super easy and fun days. Everyone that is interested should give both a go.