By David Jebb, first published in Hang Gliding & Paragliding magazine, July 2006.
Photos by Bill Armstrong
If you follow some of these suggestions, you will minimize your chances of having a launch accident.
Statistics reveal that approximately 40% of flight accidents occur during the take-off phase of flying. I believe that this extraordinarily high accident factor can be signifantly reduced by proper training and developing perfect launching methods. If you follow some of these suggestions, you will minimize your chances of having a launch accident.
The paraglider take-off should mirror an aircraft take-off. All too often we watch paraglider pilots doing “jackrabbit” or “hopping” launches. Imagine yourself in a commercial jet rolling down the runway, hopping and skipping over the ground on take-off. There’s no question that this type of take-off would put most passengers in a state of panic! Yet we witness jackrabbit hopping launches daily at many of our local sites and think nothing of it.
What we have to understand is that lift-off is a function of airspeed and/or lift over the canopy’s surface. All aircraft have to reach a predetermined airspeed before lift-off can occur. Pulling the aircraft yoke back before reaching critical airspeed will result in a temporary lift-off for a powered plane, but without the proper airspeed the aircraft will drop back to the ground. This clearly illustrates that lift-off is a function of airspeed and/or lift over the glider’s surface and not brakes.
To elaborate on the lift factor: We all understand that a paraglider can lift off without any forward running speed. This is accomplished by simply moving into the rising airflow that is normally found near the bluff’s edge. However, moving one’s glider into the rising air will cause lift-off only if the glider is at apex (directly overhead). If the glider is behind or forward of the apex/straight-up position, lift-off will be temporary at best or will not occur at all. While airspeed is an important factor in lift-off, a smooth lift-off will not take place unless the glider is perfectly centered overhead.
The primary reason for take-off accidents is glider deflations. A significant launch deflation close to the ground will often result in the pilot rotating into the bluff, or stalling one side of the glider, causing a reverse rotation to the ground. Deflations occur more easily if the glider is forward or behind the apex (not centered overhead) on take-off.
Many take-offs involve launching in turbulent or thermic air, and the glider is most vulnerable to deflations when not fully loaded and directly overhead. Therefore the two most critical factors to a safe lift-off are having the glider fully loaded and having it directly overhead. Understanding this principle is the key to minimizing your take-off risks.
- Launch directly into the wind: Pilots will often run off launch not directly into the wind, allowing the wing to be pulled off launch instead of being flown off the launch directly into the wind. This demonstrates a lack of control and inadequate piloting skill.
- Accelerate gradually: We frequently observe pilots taking off running once the glider is overhead. Going from zero miles per hour to 10 miles per hour in three steps will inevitably place the glider behind the apex. Pilots must learn to accelerate in such a manner that the glider is always directly overhead.
- Fully load the wing: As airflow and lift increase, so should loading. Additional loading causes the glider to move faster through the air. (Remember that critical airspeed is necessary to create lift-off if you are not in the lift band.) Also, a fully loaded glider is more resistant to deflation.
- Get the wing centered overhead: “Fully loaded and perfectly overhead” create the most deflation-resistant configuration for a paraglider. If you leap off the bluff with the glider behind you or in front of you, your chances of sustaining a deflation are increased.
Once the glider is inflated, from either the forward or reverse inflation, increase the forward speed gradually. It is important to lean into the harness. Standing upright and bending forward at the hips is the least effective way to load your wing. In other words if you bend forward at 90 degrees and start running, every time you hit lift or a gust, your body will tend to straighten upright, causing you to lose constant loading and decreasing your ability to maintain a constant running speed. The best method is to gradually lean forward to 45 degrees during the lift-off. In this position the loading on the wing remains constant, thereby making it easier to create airspeed and lift-off.
There are several styles to effect this take-off technique, sometimes called the “torpedo” launch. First, in Figures 1 and 2, notice that the pilot is not bent at the hips, but rather his body is in a straight line leaning forward. Hand placement can be to the rear and raised behind the pilot (Figure 1), or raised in a forward position held about chest high.
(Some pilots are unable, due to prior injuries or inflexibility, to raise their arms from the rear position; therefore the hands-up position will more easily work for them – Figure 2.). The head should be held up, looking forward and not downward at the ground. In most cases the belly harness buckle will be shoved squarely into your sternum and while it may create discomfort, this is the proper position.
In the reverse inflation, once the glider is stabilized overhead in the apex position, start moving slowly backwards into the wind. Too often the pilot stands stationary in the reverse position and as he turns to face into the wind he inadvertently takes a step or two backwards causing the wing to drop slightly behind the apex. Moving backwards into the wind while turning creates one continuous forward movement. “Once a body is in motion it tends to remain in motion,” according to Isaac Newton.
It is difficult to develop enough airflow over the wing if you are using brakes excessively. Learn to utilize shoulder and body input to make minor corrections on your wing while moving into the wind. It is important to move under the wing and not away from it; keep your body centered under the wing at all times during the take-off.
Brake pressure should be slight, so that the pilot can feel the wing. Brake pressure will lessen as airspeed and loading increase. All too often, pilots assume that lift-off is a function of brake usage; however, you should now understand that lift-off is a function of proper apex, loading and airspeed/lift over the canopy surface.
Avoid distractions. Your first focus and primary responsibility is to climb out and get as far away from the ground as possible. Additional ground clearance assures more time to work out problems, should any occur. After lift-off, continue going straight out as long as you’re climbing. Once you start to level out you have established the outer edge of the lift band as well as gained the maximum ground clearance.
Ideally, you’ll either get into your harness before or right after lift-off. However, if you don’t slip into your harness easily immediately after lift-off, don’t worry about it. Again, your first responsibility is to climb out and obtain ground clearance. If you are still not in your harness after leveling out, turn back into the lift zone and, once safe, get into your harness.
Getting into your harness should happen almost effortlessly. Remember to avoid rocking and swinging back and forth trying to get seated; this will create unequal loading on your wing. Don’t let go of your brakes in an attempt to push yourself into your harness (see Figure 3). You can use your biceps or forearms pressed against your risers during the launch to press your backside firmly against your harness (Figure 4). As long as you stay bent at the knees, leaning forward and have enough airspeed to create a perfect lift-off, getting seated will eliminate one major distraction. But again, this should not be attempted until one has mastered a perfect takeoff. If you are not able to initiate a perfect lift-off, then do not attempt to get seated until you have cleared the ridge. Many pilots utilize a double-step speed system to assist them in getting into their harness.
The above launch training doesn’t have to be conducted at launch, but can be practiced on level or slightly sloped ground. So often we discuss ground handling only in the context of inflations and kiting. Turning smoothly and simulating running off launch with the wing centered overhead and fully loaded can also be practiced in the kiting field.
Remember that any time you are able to fly off the ridge prior to stepping into the lift zone, you have put your glider into its most deflation-resistance mode. Lift-off occurs when the glider is directly overhead, is fully loaded and has reached proper airspeed.
In my opinion the third and most important aspect of ground handling (inflations and kiting being the first two) is launching, yet in most instances this is the least emphasized aspect in ground-handling training. Simply stepping into an updraft and becoming airborne is not a launch “technique.” My own experience in refining launch techniques has ensured more solid, safer, deflation-resistant launches even in the most radical conditions.