Far too often we see people stalling out of the sky. These pilots usually turn out to be habitually flying with too much brake, sometimes through having their brake lines set too short. Quite rightly new gliders are supplied with brakes set at a length that should be safe from stall when completely released. However, many things affect the the way brakes behave:

1) The height of the suspension points on the harness. They may be anywhere between just above the waist to almost shoulder height. This variation affects the position of the brake handles relative to the pilot.

2) The posture of the pilot.

3) The shape of the pilot. Is he able to scratch his shins without bending or is he a perfectly proportioned Adonis like myself?

4) How high the pilot likes to hold his arms.

5) How the pilot grips the brakes. Some pilots like to loop the handles around their wrists or even fly with wraps the whole time. I just sort of hook my fingers on to the handles.

6) How strong the pilot is. A strong pilot may tend to apply more force to the brakes and pull them lower without realising it. Some people like to feel large forces in the control lines.

How much brake should we use? Glider characteristics vary but in general we should apply enough to 'feel' the glider but not so much that our airspeed is too low. Depending on glider characteristics we may be able to reduce our minimum sink rate a little with larger amounts of brake but, generally, in all but the smoothest air the small gain is not worth the extra risk. There is a little truth in the belief that applying more brake tends to reduce the risk of a collapse but there are major penalties too. As a glider is slowed down by applying more brake two major changes take place. One is that the distribution of lift across the wing alters both chordwise and spanwise. The other is that the air pressure inside the wing falls dramatically. This 'inflation pressure' is proportional to the square of the airspeed. Put simply, at, say, 45 kph the air pressure inside a wing is about twice what it is at 32 kph. At the lower speed although the wing will be pitched up more the pressure inside will be very low making it more prone to collapses which are likely to be bigger and more difficult to recover.

'A glider with high brake pressure (tension in the brake lines) has high inflation pressure.'

Wrong! In fact if anything the opposite is true. The inflation pressure is mainly related to airspeed. The more force a pilot feels on the brakes the slower he will be flying and the lower the inflation pressure will be.

'Adjusting the length of your brake lines is tricky and dangerous.'

It does not have to be. You should be prepared to adjust the brakes on your glider.

1) Learn to tie a bowline (the bunny comes out of his hole, runs around the tree, and back down the hole) or a fisherman's knot.

2) Decide if your brake lines really do need adjusting. If you cannot figure it out for yourself then get someone to watch you fly and check whether you are flying with the trailing edge pulled down too much.

3) Decide whether you wish to lengthen or shorten the brake lines.

4) Measure the lengths your brake lines are set to so you can restore the original settings later if you wish.

5) Adjust the length of the lines by between about 25 to 40mm (1 to 1.5 inches) making sure that the lengths are equal.

6) Fly and see how you get on.

7) Limit successive adjustments to a maximum of 40mm.

When fully released brake lines normally bow visibly in the airstream. If it seems a big effort to get the lines slack they are probably set too short for you and your rig.

We adjust a car seat and controls so that we can get our preferred posture and reach the controls comfortably. The same applies to the harness and brake lines on our glider.

If the brake lines are set too long it may be a little harder to pump out a big tuck and ground handling more difficult. Bear in mind that ground handling is generally harder with harnesses which have higher suspension points because the brakes need to be set longer and the glider is pulling the pilot from a higher point on the body when reverse launching. Once airborne, if the brakes are set too short, the pilot may find that his muscles stiffen up because he has to hold his hands too high. It is important to be able to relax.

A classic problem can occur in rough air when a pilot begins to tense up. There is a natural tendency to hang on tightly to something when we are a little afraid, especially if we are up high and the natural thing to hang on to on a paraglider is the brake handles. A vicious circle can develop where the pilot inadvertantly brakes too much, has a rough ride, becomes more tense and unknowingly brakes even more until his airspeed is too low and a gust gives him a bad collapse.

Active flying refers to a number of techniques used to reduce tucking in bad air. We have seen above that flying with some brake will reduce the tendency to tuck a little. However, in the event of a significant tuck, low airspeed and consequent low inflation pressure is bad news. Our 'pumps' to re-inflate the wing will be far more effective with a good airspeed. After pumping out a collapse it is important to release the brakes sufficiently to recover any lost airspeed.

Tucks do not usually occur without some warning. Before the wing actually tucks we may see or feel the canopy surge forwards to which we can respond by applying brake. When a glider is about to tuck we may also feel a loss of tension in one or both brake lines. By responding to such a warning with a small but rapid pump we can often prevent a tuck from happening at all, or at least reduce the size of the tuck when it happens. Simply give a small pump for a small loss of brake line tension and a big pump for a large loss on the appropriate side. A related technique is to simply try and maintain a light, even tension in the brake lines at all times. As a line slackens the pilot pulls it until the tension is restored and correspondingly lets it out to relieve excess tension as the glider stabilises. In the event of a large tuck the pilot will still have to use corrective pumping but this method can give very smooth control. Using either or both of these techniques an experienced pilot can begin to sense the extent of tucks or other disturbances and often correct them without having to look.

Our objective is to keep the wing moving through the air as evenly as possible. As well as keeping the wing overhead in rough air a good technique is to use our brakes to try and keep the airspeed constant. The best guide to airspeed when everything is rocking about is probably the wind noise through the risers. We can use our brakes to try and keep this noise fairly steady by applying brake when the noise increases and relaxing when it decreases. This technique can help to stabilise our wing even when we are disoriented and is very effective in cloud. To do this we must be able to hear well. I have an allergy to ultraviolet and since starting to fly with a full face helmet and protective visor I have found this technique more difficult. The visor impairs my hearing and stops me feeling the airflow on my face. Loud variometers and radio systems are bad news in this respect too. We cannot have everything.

There is a lot we can do to keep our glider flying when things get rough. For all that, on a marginal day, the decision most likely to to keep you safe is the one to stay on the ground.