2-Line Wing Manual – Pura Vida Paragliding

A growing number of pilots are flying 2-line paragliders just for fun, with no intention of competing.

You probably always hear that only the "elite" of competition pilots are capable of flying those wings and the rest shouldn't even try.

In reality, when flying under "normal" conditions, flying a 2-line wing doesn't have to be any more unsafe or dangerous; it's just a little different, and you need to follow some rules in order to fly relatively safely. But overall, it is somewhat less "safe" compared to flying a 3-line wing.

Why fly a 2-line paraglider?

– Exceptional performance in weak conditions
– Exceptional performance when flying into a headwind
– Exceptional ascent performance due to the ability to “hunt” small rising bubbles
– Exceptional performance when flying at half throttle or full pedal (depending on the design)

Why is the performance better?

1.) Fewer lines, less parasitic resistance, more elongation, better Reynolds number.

2.) Due to the self-stabilizing profile (the center of lift remains directly over the As lines, the front half of the wing adjusts freely to the approaching air due to the “hinge” placed between the As and Bs lines (like the keys of a piano, each drawer finds its perfect angle of attack by itself).

3.) As a consequence, this leads to an improvement in the ability of 2-line wings to catch small rising “bubbles” by adjusting each group of boxes to the perfect angle of attack (spontaneously, without any pilot intervention) something that a 3- or 4-line wing cannot do due to the restriction on “cordwise” movement.”

5.) Even when flying at high speed, the angle of attack on these wings can be perfectly controlled with the B lines, without any added drag (by applying brakes) or unwanted profile distortion (pulling on the C band, on a 3-line wing distorts the profile and decreases performance).

What are the dangers?

1.) Objective hazards
It is clear that when a 2-line wing suffers a major collapse, there is not much resistance due to the lack of suspension cascades; in other words, a collapse of line A is like a collapse of A, B, and C on a 4-line paraglider or a collapse of A + B on a 3-line.

The 2-lines only work (maintain their profile, rather) thanks to the high amount of "spanwise" tension in the wing (especially when using the pedal). This is when the wingtips have a higher ANGLE OF ATTACK than the center and load a large amount of tension on the leading edge.

If that "spanwise" tension is eliminated due to a large fold of the entire wing, it tends to collapse and makes it more difficult to recover compared to a wing with 3 cascades of lines, which does not depend as much on "spanwise" tension to remain consistent.

This leads to the conclusion that a really big collapse on a 2-line wing is of uncertain outcome and should be avoided at all costs.

Another objective danger is the fact that, due to the "hinge," applying the brakes and using the 50% pedal can create a lifting force in the "hinge" area and cause a collapse.

So when flying with more than 501 TP3T of throttle, DO NOT touch the brakes. Pilot using only the B-risers.

It should be understood that flying over a pedal-driven 50% and suffering a collapse can result in a disastrous cascade of events and the wing may end up in an unrecoverable state – the same applies to most high-performance 3-line and 4-line gliders with top speeds above +60 kph

So when flying above 50% of throttle you must ensure that you can manage the wing's angle of attack in order to avoid causing a collapse.

Below 50% of throttle, unforeseen events happen at a manageable speed, but even so, the risk of a disastrous cascade of events is greater compared to wings with less aspect ratio and more levels of suspension (3 or 4 lines).

Flying above the pedal-driven 70%, the wing is VERY fast, so incidents or collapses are expected to happen very quickly.

2.) Psychological dangers

The 2-line wings feel so stable on the pedal due to their self-stabilizing profile that the faster you fly, the more solid it will feel (at least up to a 50% or even a 75 % on the throttle pedal), so someone who is used to flying a lower-performance wing might be tempted to underestimate the level of turbulence they are flying in.

Glide – The glide into the wind is usually much better than expected. This can lead to overconfidence in the wing, causing the pilot to overlook the possibility of finding downforce during transitions (especially near high mountain passes connecting long valleys). At this point, the wing's performance will be almost as poor as any other wing in the same situation.

Very turbulent air – Because 2-line wings are extremely robust, the most dangerous incidents occur in very turbulent conditions. Once the wing loses its shape (especially horizontal tension), it reacts less predictably compared to a 3- or 4-line wing, with a more explosive stall. The psychological danger here is evident; the wing exhibits a “Dr. Jekyll and Mr. Hyde” type of behavior. It is more robust up to a certain point, and as soon as that invisible boundary is crossed, it instantly becomes much less predictable compared to a standard wing, with less aspect ratio and less need for constant internal tension.

WING BEHAVIOR Ds

1.) When flying above 50% of the pedal, do not touch the brakes.

2.) When applying the speed pedal, always use the B-track risers to control the wing

3.) NEVER fly in very turbulent or downwind conditions, coming from a 3 or 4-line wing, especially at the beginning, as the pilot may underestimate the real strength of the turbulence because the wing feels more solid.

4.) Be cautious, due to the high performance, especially with a headwind – you will find yourself flying in situations that you would never attempt with another wing with less performance, but turbulence tends to increase with wind speed, so you could be exposing yourself to a considerably greater danger of encountering very turbulent air.

5.) Managing collapses
When you see a collapse starting to develop, apply an immediate, sharp pull of the B line on the side that is starting to collapse (or on both sides in the case of a central collapse).

Some wings react better to pulling the B line in a backward arc, others to pulling the B line further down – check which method eliminates more speed – in theory, the latter should be the most effective method.

The amount of thrust from the B-lines corresponds to the discharge from the A-lines. It is necessary to practice in semi-turbulent air and know how to modulate the thrust forces of the B-line in order to keep the wing in a straight line.

When you experience a stall with the wing accelerated, act quickly. Pull back the B-lines first—do it fast and hard. If that's not enough, release the throttle pedal. This will increase the wing's angle of attack, although it will also relieve some leading-edge tension. However, in some situations, it might be better to stay on the bar and simply use the massive B-line input.

As a last resort, release the pedal, then release the Bs and give the brakes a hard pull to restore a positive angle of attack and get rid of the collapse.

If all else fails, keep the wing in a semi-stall brake configuration and wait until you enter a pre-stall/full stall or enter a parachute configuration. Then slowly release the brakes as if flying out of a stall or parachute, depending on what happened before.

If an asymmetric collapse occurs, then—if possible due to your height above the ground—follow the direction of the collapse at a 90° angle with your body and attempt to recover by winging over. This re-tensions the lines as quickly as possible and minimizes the chance of wingtips becoming entangled and forming a knot. This method is preferable to counteracting with body weight and pumping the brake opposite the wing that is no longer flying.

6.) Spirals for losing altitude: they do not work as well as on lower category wings, the performance is so good that a healthy rate of descent is not achieved and the spin becomes very uncomfortable, better use large ears (if your wing is capable) or use an Anti-G parachute instead.

7.) Landing: In small landings or top landings be aware of the long final glide that these gliders have.

8.) There's not much difference from any other high-aspect-ratio wing; handle it carefully and don't force it. These wings like to be flown. You need to fly them for many hours to fly comfortably.

Translation by Schnellcraft.