How to Land a Paraglider

Sure you’ve probably covered how to land a paraglider in your initial training, but it doesn’t hurt to rethink and critic your landing techniques in your first couple of years of paragliding. Once you start paragliding on your own, this is where some bad habits or bending the rules can occur. Self awareness is key to becoming great at paragliding (along with many other things). And let’s face it, if you don’t get good at landing a paraglider, you might not get to fly again!

There are many factors which influence your landing such as thermal activity, wind, your wing and paraglider setup, the speed and angle you’re approaching at, and the surface you wish to land on, just to name a few. No two landings are the same, but obeying the right principles will put you in a better position to successfully land.

Plan Your Landing – Avoid Spontaneous Landings Where Possible

Mistakes are often made when pilots want to land suddenly. This usually results in overuse of braking, losing too much speed and stalling, or not properly scoping out the landing zone for hazards. The best landings are well thought out and factor in the possibility of sudden wind change, as well as hazards such as trees, powerlines or jagged rocks which could damage your wing.

The first step is to determine if there’s any wind drift, and if so, what direction it’s going in. This can be checked by visual markers at ground level such as tree blowing, wave ripples etc. Your GPS (all pilots should carry one of these) can also be used.

A common mistake is to focus mostly on the launch area and not plan the suitability and weather conditions of your landing zone. In many cases it’s safer to land on green fields, rather than near the water as the thermal conditions here may make landing a less stable experience. The weather conditions should also be considered for the time you wish to land. You may find that some areas have higher thermal activities in the afternoon and that it’s best to get your flight in earlier in the day so you can enjoy a smoother paragliding landing.

It’s important to consider the slope of the landing zone in your landing strategy. If there is a slope, combined with a tailwind or some thermal lift, you’ll need a longer final glide. If you’re planning your landing from a high altitude, you may want to do two-stages of planning, firstly by performing some figure of eights to work off the altitude and then lining yourself up and planning the second stage of landing from a lower altitude.

man landing a paraglider next to a lake

Keep Your Eye on the Landing Zone

Keep your eyes on the spot you wish to land on and use your knees as a sight. This helps you to concentrate and focus. If the landing zone rises up, this means you’ll land short of your target. If the landing zone drops below, you’re going to fly over and past it. Line up the landing zone early so you can avoid turning later in the landing.

Legs Down!

Getting your legs into position can seem like a pretty small and insignificant part of landing a paraglider. But it’s one of the most common landing injuries, so it’s worth getting into the habit of always getting your legs down early.

If you stay in a reclined position until you’re ready to land, your feet will be in front of you and won’t be ready to take the full weight plus inertia. This can cause considerable force on your ankle which can easily be injured from this pressure.

Make this something you tick off your mental checklist early. Get your legs down when your about 50 feet in the air. By getting your legs underneath you, your entire feet and legs can absorb the force instead of just dumping it on your ankle.

Wing load

Paragliding for dummies Charge alaire

To fully understand the wing loading, I often ask this question when I discuss the mechanics of paragliding flight:

Obelix and Asterix fly under the same paraglider (same size), who goes the furthest?

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Definition of wing loadingAsterix and wing loading

Table of contents

The wing loading is a ratio between the PTV (total flying weight) and the area of the wing.

It is therefore expressed in kilogram / m 2 .

The average wing load of a solo paraglider is around 3.5 kg / m2.
If you fly in a two-seater, the wing load is then greater, around 5 kg / m2… and you can feel it in the controls, particularly if the passenger is heavy!

In delta, it is even higher, from 5 and up to 10 for the most efficient models.
The reason is simple: at the same weight of the pilot, the surface of the glider in hang-gliding is much less than in paragliding.
The hang glider creates less drag, so it doesn’t need to create as much lift as a paraglider.

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Wing load and speed

For a given PUL (Ultra light glider, therefore delta Where paraglider), the manufacturer establishes a weight range.
For example, for a given paraglider model and a given size, it could be 75-95 kg.

Depending on whether we are at the top of the weight range (here 95 kg) or at the bottom (75), the behavior of the wing will be different, because the wing load will vary, mainly due to the variation in weight. of the pilot.

If Obelix weighs twice the weight of Asterix, and Asterix flies at 35 km / h, what will Obelix’s speed be, if he borrows his paraglider?

Let us recall two equivalences making it possible to obtain the RFA (Resultant of the Aerodynamic Forces):

  • RFA = 1/2 C ρ SV 2
  • RFA = Weight

We can therefore deduce that:

  • 1/2 C ρ SV 2 = Weight

So, to come back to our Gauls, the difference in speed varies according to the variation in weight:
With Po = Weight of Obelix,
Pa = Weight of Asterix,
Vo = Obelix Speed,
and Va = Speed of Asterix

  • (1/2 C ρ S Vo 2 ) / (1/2 C ρ S Va 2 ) = Po / Pa
  • ( 1/2 C ρ S Vo 2 )/( 1/2 C ρ S Go 2 ) = Po / Pa
  • Vo 2 / Go 2 = Po / Pa

or Vo / Va = √ (Po / Pa)

Conclusion: the speed of the sail varies with the square root (√) of its PTV

If the PTV doubles, as is the case in this example, assuming that Obelix weighs twice the weight of Asterix, the speed gain is “only” 41% greater (√2, ie 1.41).
If Asterix’s PTV is 65 kilos and it carries 5 kilos of ballast, its speed only increases by 0.37%. √ (70/65). In short, it would then go at 36.3 km / h, instead of 35 .

To note that all speeds increase, horizontal speed, like vertical speed (sink rate).
And as finesse is the ratio

  • Horizontal distance / Vertical distance
  • Horizontal speed / Vertical speed
  • Lift / Drag

We can therefore conclude, to come back to the initial question, that Obelix and Asterix will arrive at the same place (same finesse). But Obelix will arrive sooner (higher sink rate), and faster (higher horizontal speed). I’ll let you calculate how quickly Obelix will arrive.

Wing loading and wing behavior

Here we will take the fable “The oak and the reed” to explain the subject.

A pilot “at the bottom of the range” (of weight) will be like the reed: He will be more sensitive to turbulence, therefore his paraglider more inclined to close, but without too many consequences. Like the reed, it bends but does not break.

The one at the top of the range will suffer less from closures, but when they do occur, they will be more violent.
This is for two reasons. First, the internal pressure in the sail increases (with increasing speed). Then the more loaded pilot generally flies more braked, so as not to fall out of the sky. This results in a greater impact. These two factors explain that the sail is in this case less prone to collapses. On the other hand, they will be more violent for the same reasons: More speed, more inertia, largely negative impact .

The more a paraglider is loaded, the more speed it will have . horizontal, but also a poorer, greater sink rate. It’s good to gain speed, but if you climb less well, and less high.

In general, we spend a third of the flight time in thermals, which leaves you wondering. In short, everything will depend on the conditions of the day.

Wing size and performance

It is often said that the heavier pilots have an advantage, because if Obelix flies with a wing adapted to his size (or rather his weight), he will fly better than Asterix with his smaller wing.

the reynolds number which partly depends on the surface exposed to the flow (wingspan * thickness of the profile), explains that a larger sail generally flies better. We can also say more simply that the induced drag decreases. This is notably due to the marginal vortices which form on the stabilizers, but as the “useful surface” of the sail increases proportionally, the lift increases, and therefore the finesse too.
This is how light pilots in competition ballast themselves to fly on a larger model… up to 33 kilos (22 in 2020). A real aberration!
But the “total flying weight” increases with the surface of the sail, the wing loading is therefore respected.

It is to fight against this injustice that Bruce Goldsmith created a specific competition: the BGD-Weightless, in 2020 in Roldanillo.

And in Mexico?

TO Valle de Bravo, in high season, the conditions are rather muscular: powerful thermals, fairly strong breeze, convergences, in general I take a little more ballast than usual to go paragliding, so I increase my wing loading.

Conclusion

In this article, we have therefore seen that the wing loading does not influence the trajectory (or little, as long as there is no wind), the fineness of the paraglider remains the same (Cf polar gears) and on the other hand, the behavior of the wing will be modified, and the piloting adapted accordingly. If you are having trouble judging your height to enter the final, this article may be of great help: Landing precision.

Condorito

Paragliding pilot for more than 20 years, I am also the founder of this website.
Instructor at Grands Espaces paragliding school in Annecy (French Alps), I migrate to Valle de Bravo, Mexico, in the winter.
See you around ! Know more

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How fast is it? How we test paraglider speeds

Measuring the performance characteristics of a paraglider, including paraglider speed, has always been notoriously difficult. But new tools are allowing pilots and manufacturers to do just that. Cross Country’s Hugh Miller reports on speed tests he’s been carrying out for the last year

Flymaster’s new True Air Speed (TAS) probe

Flymaster’s True AirSpeed (TAS) probe

When Flymaster’s new True Air Speed (TAS) probe was released a couple of years ago we started to measure the trim and top speeds of the paragliders we review. However, we’ve been very surprised by the results. In short, paragliders really aren’t as fast as most pilots – and manufacturers – believe they are.

First, a bit of science. It’s obviously important for powered aircraft pilots to know their exact speed. However, despite any effects of wind, planes go faster at altitude than at sea level due to the lower air pressure – that’s why passenger jets cruise at such high altitudes.

Their instruments rely on pitot tubes to measure what’s known as their ‘Indicated Air Speed’ – which gives the same speed reading regardless of whether the plane is flying at sea level or 30,000ft. When a pitot tube freezes up, it can have disastrous consequences, as the pilots lose any indication of their stall speed. This is what is thought to have contributed to the Rio-to-Paris Air France flight 447 crash in 2012.

Explaining the instrument
In paragliding and hang gliding, we’ve long relied on propeller-based air speed indicators and GPS figures, to give us our speeds. But neither of these are accurate. In fact, the effects of altitude alone will mean that in still air, a paraglider flying at a top speed of 51km/h at just above sea level would be flying at 58km/h at 3,000m. You just go that much faster in thinner air and propeller-based air speed indicators don’t compensate for this.

Obviously you don’t want to be re-working out the stall speed of your Boeing 747 at different altitudes, hence the importance of indicated air speed, measured by pitot tubes. A GPS speed figure doesn’t make this compensation for differences in temperature, density and pressure – and of course doesn’t factor in wind speed and direction, either. GPS is great for accurate ground speed, but useless for air speed.

The boffin test . Our speed probe in Oxford University

The boffin test … Our speed probe in Oxford University’s wind tunnel

Anyhow, we were so surprised by the low readings our Flymaster TAS probe gave us that we sent it to Oxford University to be checked against their calibrated hot-wire anemometer. Hot-wire anemometers have been used for many years in the study of fluid dynamics. They are extremely sensitive and are almost universally employed for the detailed study of turbulent flows.

Adrian Thomas, a former British Paragliding Champion and regular contributor to Cross Country, ran the tests in Oxford University’s wind tunnel – where normally he tests the aerodynamics of small insects.

“A pitot tube like Flymaster’s gives you a reading that reflects the forces acting on the pitot tube, and those vary in exactly the same way as the forces acting on the wing”, Adrian explained.

“The Flymaster TAS probe gives a nicely linear result”, he told us. “It slightly over reads – the real air speeds are consistently a fraction lower than the given figures across the 20-60 km/h range.”

“All pitot tubes need regular calibration, and it’s something sailplane pilots put a lot of effort into. NASA have also developed a calibration system between GPS figures and pitot tube figures, and it would be easy technology for instrument manufacturers to bring into paragliding”, he explained. Current methods used for aircraft pitot tube calibration include trailing cones, tower fly-bys, and pacer aeroplanes, which are all obviously time and cost intensive. The NASA method could actually be incorporated into paragliding instruments in the future.

airspeed-definitions

Following the wind tunnel tests Adrian gave us a recalibration formula to calculate precise indicated air speeds which match GPS speeds at sea level. Going forwards, we will be using these results to inform our glider reviews, recalibrating our Flymaster TAS probes at six-monthly intervals.

To be absolutely sure that we can have faith in what our calibrated TAS probe tells us, I spent a day cycling up and down the seafront with the TAS probe and three GPSs. The TAS was wobbling a little on the shorter string dangling from my handlebar, but its reading was steadily consistent with the GPS ground speed.

It is worth noting that most manufacturers obviously don’t go through this whole rigmarole – they just compare their new prototype paragliders against their previous models, and measure what’s known as the ‘delta’ – the difference between trim speed and top speed. For CCC class, they report the speed system travel associated with that delta. So, for example, the Boomerang 10 has 15cm speed system travel, and a delta of 18km/h.

Does it matter?
Does top speed really matter? In competition, of course it does. Some test pilots claim the latest CCC wings are capable of 67km/h. In our view, this is an impossible Indicated Air Speed figure. We’ve tested the Ozone R11, widely regarded as the fastest paraglider ever made, and recorded a maximum of 65km/h. The R11 we tested featured standard risers, not extended risers which allow even further travel. CCC wings don’t feature trimmers like the R11 and have necessarily been restricted.

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Airspeed of CCC paragliders

“I hardly ever see ground speeds consistently in the 60s, and I use full bar a lot”, said Adrian, who flies a Boomerang 10 and is also involved with glider development at GIN.

“On the other hand, I go as fast as anyone else so what does it matter?” he asks. “There is a little maturity appearing in the comp scene. Pilots have realised that trimming their wings fast means they lose out on climb and particularly on the gains you get going straight in lifty air at trim. At the most recent Superfinal, the wings that were checked were all within millimetres of manufacturers’ defined trim settings.”

Glider examples
We measured the top speed of some of the hottest three-liners: the UP Trango XC3, Ozone’s M6 and the GIN GTO2. Using the Flymaster TAS probe, we measured a top speed of 50-51km/h for all three wings, flown at 3kg below the top of the weight range. The new 777 King is a little quicker. This is indicated air speed, and should be the same at sea level as at cloudbase.

Airspeed of EN D paragliders

Try telling an EN-D pilot that though, and they’ll likely be a little shocked. They may also say they have recorded a GPS speed of 55-56 km/h when flying in the still evening air in the Alps. Both of us, however, are telling the same story.

Problems with measuring speed
However, obtaining accurate results using a TAS probe still isn’t easy. Thermik magazine editor Norbert Aprissnig told us: “We too have looked at providing accurate speed figures for our reviews but it has been a learning exercise in just how difficult it is to get accurate figures.”

He added: “Although modern TAS probes allow for automatic compensation for temperature and altitude, we still have to make sure the wings are in stable flight before taking measurements. Air movements cause fluctuations and we as test pilots end up filtering the data as best we can.”

How to test airspeed on a paraglider

Also worth noting is the instrument’s wind-speed indication. Most instrument systems, including XCSoar and the Oudie, provide information on wind direction and strength, but as you’ll know if you’ve ever used them much, the figures fluctuate enormously. You have to be flying consistent circles for the instrument to generate an approximate calculation. However, a pitot tube system like the Flymaster TAS is the only way to obtain accurate wind information as it will run a precise comparison between your aircraft speed with your GPS speed.

Finally, just to confuse things a little, Flymaster’s TAS probe stands for ‘True Air Speed’. From an aviation perspective, this is misleading, as ‘true air speed’ is different from the ‘indicated air speed’ that we’re interested in – the bald, pressure-based truth of an aircraft’s speed irrelevant of altitude.

What does it all mean?
Perhaps unsurprisingly the figures reveal that as a sport we have regularly over-estimated the speed of our wings. Just as one example, some pilots claim their paragliders have a trim speed of 40km/h. Meanwhile, Moyes states a trim speed of 35-37km/h for their Litespeed RX competition hang glider. Spot the difference.

Airspeed of an EN B or EN C paraglider

Let’s face it, pilots are loathe to be told their ‘60km/h’ wing only really hits 51km/h, and manufacturers understandably don’t want to publicise potentially slower figures. No one wants to be slower than the next pilot, or their manufacturing rival. But our testing has shown that most ‘mid-B’s can get to around 44-45km/h accelerated, while ‘hot’ EN-B wings and many C class wings have a top speed of 46-48km/h. Only EN-Ds and a handful of the very fastest C’s make it beyond 50km/h.

Of course, top speed in still air means nothing if the leading edge is too fragile for the speed to be usable in real life conditions. So let’s not get into a bidding war for the fastest wings on the block. In our reviews we will continue to focus on a wing’s usable speed range, accelerating through turbulent air to test its rigidity and cohesion, as this will always be a better indicator of a good, fast wing than any number.

This article was first published in Cross Country 172 (August 2016). Hugh Miller is a review pilot for Cross Country Magazine and UK XC League Champion 2016. If you enjoyed this sample article, perhaps you’d consider subscribing and supporting the world’s only international free flying magazine?

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Source https://globalparagliding.com/paraglider-landing/

Source https://parapente-mexico.com/en/mecanique-de-vol/wing-loading/

Source https://xcmag.com/magazine-articles/how-fast-does-it-go-testing-paraglider-speeds/

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