BUTTERFLY LANDINGS by Anthony Allen

I think it’s vital that whoever reads this and hasn’t got butterfly landing right yet, should NOT go out there and try them without the appropriate guidance/supervision of an instructor (who can do these) and ALTITUDE for
the first time.

Ostensibly butterfly landing is a consistent and repetitive approaches to the point of stall. On NEARING the stall point the glider is allowed to regain normal flight by releasing the brakes. As it pitches forwards and begins
regaining airspeed, the uniform application of brakes again retards it. At all times the pilot needs to be really in tune with what the wing is doing and should particularly look out for either wing stalling (or the whole thing obviously) and this may require slight occasional asymmetric input (particularly on higher aspect wings).

If this sequence of events were to be viewed from the side as the glider flew by it would look something like someone doing controlled pendulums, except the frequency would be greater and the pendulums shorter because the glider is not being permitted to regain full airspeed before being retarded again.

I wouldn’t really go as far to say that the technique is an emergency one, but it is also not a standard means of executing a landing. I believe it is important for every pilot to have a thorough understanding of what butterfly landing is and when and where to use it, especially with the progress of paraglider design and performance in recent years (haven’t you noticed how people are starting to use lonnngggggg final glides at speed to land?). In
getting proficient at this sort of landing it’s also not unreasonable to misjudge a glide and land up needing a way to stop quickly (fence or power line ahead). Alternatively, you may just have a confined landing area that
requires some fancy footwork to get into.

Since butterfly landing promotes breaking and re-instating the airflow over your wing in it’s controllable form (inflated) it’s best you keep it that way. Ideally one should never feel the wing “mushing”. If you’re getting to
that point you’re being to aggressive with your brake input or you’re holding then in too long. Butterflying will take you closer to the edges of the normal envelope of your wing and therefore should only be attempted by
“switched on” higher airtime pilots who have a feeling for what they are doing. I would suggest it imperative to have had some form of formal “advanced” manoeuvres training before trying this out.

There’s no hard and fast rule about how long you should hold on, back off etc, because we all have different wings and wing loadings, but you should also not come in thinking you’re doing a butterfly landing with your hands flapping about the same frequency as a humming bird. That does nothing to the wing and looks pretty daft too. On the other hand flying along, pulling and holding brakes for 5 seconds is
the other extreme.

The dynamics of executing a decent butterfly landing are also greatly influenced by where you intend doing one (top landing at a thermic site, at a coastal ridge lift site, on flat ground, behind an obstacle, etc).
Butterflying in a top-landing situation is trickier for the simple reason that your relative airflow is not laminar and therefore the velocity at which you THINK it’s passing is higher than it actually is and you get closer to stall than you anticipate.
Butterfly landings in laminar airflow are therefore a little easier and perhaps a little safer.

The other trick is if you have to use one to get into your desired landing area and you can see you are too high on final glide, but don’t have enough height to go around again, it’s not a bad idea to use it as part of your
approach while still quite high and then exit onto a faster approach and flair to spot land. Sounds simple, but keep practising – it’s better to have the experience than to try one when you find yourself needing one and then
blowing it.

By the way, the typical sink rate one can achieve in a well executed and controlled butterfly landing in stable, laminar airflow is about 1.5 to 2 m/s, again a good reason to learn to land your glider correctly first.

Butterflying in a top-landing situation is trickier for the simple reason that your relative airflow is not laminar and therefore the velocity at which you THINK the air is passing over your wing is lower than it actually is and you get closer to stall than you anticipate

LANDING IN CONFINED SPACES AMONGST TREES

This seems to be a problem in South Africa especially with the pilots flying XC across the bushveld where numerous thorn trees hamper our landing efforts.

Most pilots forget that their wing is wider than they realize and often they snag the wing tips, lines etc, which results in swinging the rest of the wing towards the obstacle or tree thus creating more wing in the tree.

With modern gliders having such effective glide ratios we seem to need more space to land in.

Again, I would suggest picking a spot cross wind (so to eliminate landing short or long) or directly into wind (if it is at constant speed) as far away from the wind shadow potentials as possible. Applying BIG EARS and keeping them in until landing (VERY IMPORTANT!!-never let big ears out near the ground, else you risk a spin/stall situation) will reduce your glide, limit your gliders’ wingspan and should see you making it into the small space.

Obviously the landing is faster and possibly a little harder due to the increased angle but will see you giving yourself less opportunity to snag the wing. I find a big ears entry with a good hard flair gets me down in the smallest of spaces.

Dropping the wing once touch down would best be achieved by “rosette front tucking” the glider by pulling on both central A risers immediately followed by Full Breaks, thereby reducing its surface area and collapsing the wing down behind you. Another method is pulling down on only the A riser on one side followed by both brakes in short succession. This should twist the wing as it collapses ensuring the falls on the collapsed wingtip. These need to be practiced on open landings

As always a good approach and knowing which direction the wind is coming from aids in this type of landing. This is also a possible place where a butterfly landing could be implemented but this will not reduce your wing-span area but should shorten your landing distance required.

The above methodologies does not take into account a thermal that may release just as you come in, so there’s always the element of uncertainty, but we can limit the uncertainties as much as possible.

Preferably just stay high and land in a big open space or at Goal.

TIPS FOR LANDING ON THE SPOT

Landing a paraglider on a spot of your choosing is easier than one thinks.
Although one must be comfortable with ones wing, it is also important to know its glide and point of stall pretty well.

Most pilots want to land on the spot but do not spend enough time with the approach. This is critical, as is an understanding of the micro weather conditions, wind direction and strength, as well as the landing areas natural hazards. A good thought out approach, allowing wind change options is best.

No two landings are ever the same but the methodology applied is.
This goes with top landings as well.

A little trick I use is simple. I always keep my eye on the spot I wish to land on and using my knees as a “sight” almost – judge whether the spot is rising up above my knees or dropping below on my final glide. Keeping your eye on the spot also seems to make me concentrate more. Remember we normally hit what we look at (fixate upon). Here’s where we can use this human trait to our advantage.

Judging your glide and speed is simple if you give yourself some reference. This is where my knees or feet (if in a stirrup) provide that reference “sight”.
If my decided landing spot is rising up this means I will land short of it.
If it is dropping below then I am going to over fly it. This technique can also be used to access whether you will get to a geographical position if flying XC as well.

So how do I get to land on the spot? If I give myself a long approach with limited amounts of “S’ing” or “Figure-of-8” turns to lose altitude. If I keep the spot neither rising nor dropping technically I should land on it. This does not take into consideration ground rush due to wind gradient etc. These minor adjustments come with experience and knowing your wing.

I try to maintain a steady speed by gently slowing the glider down but maintaining an even brake pressure (about 25%) where I can allow the glider to speed up or slow down more should I need. I give myself some speed to play with. By allowing it to steadily glide to the touch down spot where I will flare just before it, I normally land on my designated spot time after time.

Another tip to landing on the spot is to approach the spot from the side. This aspect takes the wind speed out of the equation to a large extent and allows you to concentrate on maintaining the glide applying or releasing the brakes as required. Only minor directional adjustments would need to be made to hit the spot.

Note if one is flying with no brakes and then one pulls them, the glider can convert that airspeed into lift and vice versa. This subtle control comes with practice.

If you do this properly there should seldom be a need to butterfly-land your paraglider.
Give it a try and practice as much as possible. Understanding your wing and how it performs in differing conditions is key to successful spot landings time after time.