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Introduction:

The figure 8 pattern is used in a landing approach to stay downwind of the landing area. This pattern allows the pilot to pause their approach and stay in a zone downwind of the landing target regardless of how strong the wind is blowing. The “8” pattern can be done in any wind condition and can be held indefinitely until a good height is reached for the final approach. The figure-8 pattern is determined by the ground path (the path of the glider relative to the ground). The number of turns and how far the glider needs to turn is directly related to wind speed (increased wind speed and crabbing effect reduce the amount of turning necessary to hold the pattern – see below).

One of the greater benefits of this pattern is that it eliminates any direct downwind flying during the approach. Downwind, flying near the ground has the potential for danger.

There is also great flexibility while using this pattern. If lift comes along while holding this pattern, the pilot can hold this pattern and remain downwind of the landing target indefinitely. If there is a sink present, the pilot can quickly exit the 8s and head in on a final approach.

Staying downwind of the landing area means that during each pass between the turns, you need to angle the ground path slightly downwind  from perpendicular to the spot. If a pilot does not angle their ground path slightly downwind on these passes, then they are not doing the pattern correctly and will instead be doing wide S-turns and begin to get closer to the spot (see “crowding a spot” below). In light or no wind conditions, the looping turns at the end of the 8s will have to be at least 180 degrees in heading. In stronger winds, because of the inclusion of crabbing, the turns might be as little as 90 degrees in heading. If there is a 10–12  MPH wind, for example, on the cross legs, the glider would be pointed a little more than 45 degrees into the wind to have a ground path near perpendicular to the spot. So, the turns will be just more than 90 degrees to complete each turn and go on to the next leg of the approach. Instead of thinking about all of these numbers, simply adjust the pattern to have enough angle downwind (over the ground) to allow for the next reversing turn. Remember, the figure 8-pattern is your path over the ground, so making your turns and adjustments with the ground in mind is the correct way to adjust the turns and figure 8 shape.

Adjustments to the 8s include the size, location, and distance downwind from the spot. In light winds, ground speed will be higher for all sections of the pattern. In addition, in light or zero winds, there is little or no crabbing in the crosswind legs, so the turns will be more than 180 degrees. In light winds, it is better to do a slightly wider 8 pattern a bit further back from the spot. In stronger winds, crabbing will be more prevalent on the crosswind legs and the loop turns will require a turn of less than 180 degrees. This can allow for narrower loops and the ability to do the 8s closer to the target spot.

 

Avoid Crowding an Approach

A common problem with pilots learning a figure-8 approach is the tendency to creep forward as a result of doing “S” turns instead of doing full figure-8s. It is important to remain behind the planned distance downwind of the spot. If correctly done, figure 8s will keep the pilot from moving upwind while holding the pattern. You could hold a figure 8 pattern indefinitely from any height, just downwind of the spot, and wait until you reach the correct height for the final glide to the target. It is basically like staying directly above a rectangular box drawn on the ground that is downwind of the spot.

If a pilot does S-turns instead of figure-8s, they will end up too high when they get close to or above the spot. This is called crowding an approach. There are no great answers to being too high for a spot when down below about 30 ft. Turning downwind at this altitude is not safe! It leaves the pilot too low to turn back upwind and back to the spot.

When the 8s are done correctly, the pattern is held until the desired height is achieved and then the pilot can begin heading into the target landing spot. The desired height should include a slight amount of extra altitude for the glide to the spot. Soft S-turns or speed to fly can be used during the final to adjust for the extra height. The point here is that the pilot can adjust out extra altitude, but cannot extend a glide without the help of a lift. More on this later.

Wide S-turn approach / variation

An alternative to Figure 8s when the wind is very light – “less than 5 MPH” – is to start even further back and do wide S-turns. At sites that are not large enough to allow these wide figure 8s during the approach, stick with the Figure 8 pattern. For sites that have enough room, this method is easier for newer pilots.

In the below image, the S-turns can become a full figure 8 if lift is encountered. If sink occurs, the pilot can reduce the degree of sharpness in the turns. In the end, the goal is the same: to cross the outer circle at a height that will carry the pilot a little past the landing spot. As the pilot flies inside the outer circle, fine tuning with soft S-turns is used to filter out the slight extra height and dial in the landing near the spot.

“Sampling” on the way in

As you break out of the figure 8 or wide S-turn pattern and head in for the spot, you should sample your glide. What I mean by “sample” is to try to see where your current flight path will take you. To do a sample, fly straight at the spot as you cross the outer circle. Try to see where you are gliding to. To do this, look for a point on the ground in front of you that is neither moving up nor down relative to your glide. The ground below you will look like it is moving downward in your peripheral vision. In your peripheral vision above your gliding point, the ground will appear like it is moving upward. We call the point that you are gliding toward, the point of “Zero Motion”. It is not always easy to see this, but by trying to sample, you can develop a feel for the zero motion point. Remember that you want a little extra height for the final glide. If you do not have any extra height, fly at trim speed and directly toward the spot. If you have extra height, you can then work on adjusting this out via turns or speed (see below discussion of adjustments).

Adjustments

Being a little too high as you pass the outer circle will mean you need to do some S-turns on the way in or use speed to adjust your altitude down a bit. If you realize as you sample that you are way too high, you should make an immediate turn of at least 90° (ground path), but not a turn directly downwind. You can angle slightly downwind of the outer circle and basically do a figure 8 loop that will return you back to the outer circle area near the correct height. In very light winds or zero winds, you can just move around the outer circle until the correct height is there to head in again and return to sample.

Pops or Thermals  If you hit a pop or thermal while crossing the outer circle, the correct response is the same as being way too high. Make sure you wait till the glider is back overhead and then turn to keep yourself back and go back to a figure 8 type loop. If you are above about 50 feet, you can even turn a little more downwind briefly to keep yourself back.

Sink  If you are already a bit low or hit sink while sampling as you cross the outer circle, the answer is simple. Keep flying directly at your spot near trim speed. In air that is not bumpy, trim is fine. If there is some texture to the air or if it is bumpy, keep a little bit of brake on as you fly toward the spot.

Inner and Outer Circle

So, what is the target height and at what distance? I like to use a distance of a little more than 300 ft or 100 yards to do the figure 8s downwind of. I call this imaginary distance the outer circle. If you look at the wind direction and picture a 100-yard circle around the desired landing point, you can picture a line about this distance from the center of the desired landing point. You will do your figure 8s. Just downwind of this circle, and try to cross it at the correct height. This will be somewhere between about 40 ft (for very light or no winds) and 80 ft (for winds around 10 mph). For moderate winds of about 5 mph, it will be about 50 ft.

In the below picture, the circle that is 110 yards is pictured intersecting the shallow ditch at Ed Levin Park.  Most approaches will cross the ditch near the point of overlap.   Height for this distance is pretty close to 100 yards and I usually reference the height relative to the 60 foot tree at the corner of the Eucalyptus trees at the start of the ditch.

Math will help you understand why these heights work. The following table will show you why these will work for entry-level to intermediate gliders that get around an 8:1 best glide at 20 MPH (trim speed).

LZ distance and ditch location

Wind Speed / Starting Approach Height
from about 100 Yards

Wind Speed Ground Speed
(Trim Speed = 20 MPH)
Approach
Starting Height
Gliding Distance
0 20 MPH (100% speed) 40′ 8 x 40 x 1 = 320
5 MPH 15 MPH (75 % speed) 55′ 8 x 55 x .75 = 330
10 MPH 10 MPH (50% speed) 80′ 8 x 80 x .50 = 320

 

This may look complicated, but do not worry. These heights can be thought of more in a generalized sense. Picture that you need to be higher at the outer circle in stronger winds and lower in lighter winds. When you making an approach, you will look at the wind speed and make adjustments. After practicing approaches, you will learn what heights will work and adjust for wind speed. In the below pictures, you can see that there are some trees at this site that the pilots can use to cross reference their height. The trees are about 60 ft high.

In moderate to stronger winds (5–12 mph), the figure 8 pattern is easier to do because the turns will be less than 180 degrees. In fact, the turns might be as little as 90 degrees in winds near 10 mph. This is because of the effect of crabbing and the resultant direction in relation to the ground.

Higher Wind Example: Picture flying at about a 45 degree angle in a 12+ mph wind. In such a wind, to reverse direction at the end of a figure 8 loop, you would only need to turn 90-degrees.  In addition, during the turn, there is a very low ground speed and the loop will not take you much upwind as you execute this 90 degree reversal. This is why, with moderate to stronger winds, it is easier to execute the figure-8s closer to the target landing spot.

Light Wind Example: Picture flying in no wind. Between the loops at the end of the 8s, you will need to head slightly downwind perpendicular to the landing spot. This means that you would have to turn a bit more than 180 degrees with each reversing loop. In addition to this, loops will be bigger because of the higher ground speed. In addition, ground speed between the reversing loops will be much faster than in wind. The solution to this is to do a larger figure 8 a bit further from the spot for lighter winds. This will eliminate feeling cramped and allow for the bigger turns at the end of the loops and allow you to keep your distance from the spot (avoid crowding) until you have reached the correct approach height.

The below image depicts a Figure 8 Approach for a day with about 5 mph wind at Ed Levin Park. To have success in this approach, the pilot would need to be around tree-top level as he or she turns out of the figure 8 pattern into the outer circle/final approach area. In lighter winds or 0 wind, you would need to be just below tree-top level. In winds up to around 10 MPH, it would be better to be 10 to 20 ft above the top of the corner tree as you cross the outer circle.

fig8_1

The Figure 8s should be done directly downwind of the target landing spot. Imagine a pie slice directly downwind of the target spot and do the figure 8s in this. Make sure that there is always enough room to complete the turns without getting any closer than about 40 feet from the trees.

A Sample Figure 8 Approach

Do the Figure 8s in a zone downwind of the spot.

At Ed Levin, you need some imagination to de-reference the corner tree for the correct height.

fig8_2

The most important part of the approach is making the adjustments prior to turning onto final as you cross the Outer Circle. Anticipating a bit of height loss for the final turn and glide to the outer circle is important to plan for.   It is crucial that you don’t just do S turns instead of Figure 8s. If you do, you will move into the Outer Circle too high, we call this crowding your approach. This is because you will be too close to the target and this severely limits your safer options for the final approach.

Learn to cross the outer circle with a little extra height.   You can use speed and or turns to fine tune the height on the approach in.   If you are too low, there are no ways to regain the height to make the spot.  All you can do is to use the best speed to fly and hope for some lift, but this does not always happen.

Once you break out of the figure 8 pattern, you then need to continuously monitor and adjust your glide. This means looking to see if you are crossing the outer circle at the correct altitude. If you turn toward the outer circle and realize after doing so that you are going to be higher than you want, add turn or two to adjust out on the way to the outer circle. After crossing the outer circle, you can then make final adjustments. All of these adjustments need to be made as high above the ground as possible. The last 25 – 30′ of altitude should have only minor turns (less than 20 – 30 degrees, sharper turns lose altitude and this is very dangerous near the ground).

In moderate to stronger winds (5 MPH or more), above 25′ or so, you can use speed to help eat up altitude.   So, if it looks like you are going to be about 30 ft past the spot, you can fly slowly into the headwind to greatly reduce your glide.   Once you get to 25′, do not fly any slower than brakes just above the shoulders.   Landings require energy in the glider and coming in too slow can be dangerous.  Also avoid doing any sharp turns below this height.   Sharp turns have high descent rates and this should be avoided  close to the ground.  Flying slightly past the spot and landing safely is much better than pounding into the ground becaus of a low sharp turn!

In very light winds, speed will not help cut down glide much.   Instead, you will need to add some S turns just after crossing the outer circle.   At about 40 ft above the ground you can carve sharper turns still, within reason of course.   As you get close to about 25 ft above the ground, only soft turns should be done.

fig8_3

 

Eyes on the Horizon for better flare timing

When you are on the final approach during the landing, your eyes should look forward to the horizon. You might ask, “Shouldn’t I be looking at the ground?”, and the answer is mostly no. Looking at the horizon helps eliminate a few negative perceptions and improves flare timing.

When you are on final approach, you should be at a steady speed and definitely no slower than “hands just above shoulders”. If the eyes are looking down, the eyes will perceive an accentuated ground speed. Some call this “ground rush”. It is important to be aware of hazards in the terrain, like rocks, burrowing animal holes, and even vegetation that might catch your feet. But, quick scans with the eyes can address these concerns. Primarily, your eyes should be looking out at the horizon. I do not think there is a specific distance ahead, perhaps it is 50 yards, this is something that clicks once you form the habit of looking ahead.

 

Below is a video that shows 5 landing approaches.   One of them is a Figure 8 approach, while a couple of the
Downwind, Base and Final approaches use a figure 8 at the end to scrub off some altitude.  

 

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