Use of brakes when doing XC
Minimum sink for some wings is, according to the wings manual, achieved by applying some brake. Ozone says 30 cm to get the minimum sink for the Buzz Z5. So is there any reasons for not flying with 30 cm brake on your glider? We will try to point out some advantages and some disadvantages by using the brakes.
If you are doing some coastal soaring on a laminar spot, you may get a little more height by applying brakes according to the manual. You may also extend your time in the lift. But this is very rare that you are flying a such place when you are doing XC. Usually even if you are soaring, there are thermals, difference in lift, and maybe some turbulence from obstacles around you. If the conditions are marginal and you are in need for this extra lift, you need to know your wing very well, and know how to react when you fly around like that, with less energy in your wing. By applying brakes you get less energy in your wing, and you get less possibility to give the proper correction to turbulence. You also have less energy to make a nice turn when you are in the lift. It is more to gain by practice to find the place where the lift goes higher and to make good turns in the right spot.
The feeling when you are hitting turbulent air, may be better when applying brakes. It get less bumpy as the speed is reduced. But your glider is ok with the bumpy air, it is very stable and is very resistant to collapses even on trimspeed. Older gliders needed to have a little brake to tighten up the leading edge. But modern gliders don't have that need. To work with the feeling, we recommend you to practice flying with speedbar instead, and when you hit turbulent air, you can go off the speedbar or just release it just a little. If you use your speedbar or back raisers to catch the pitch movement, you will get a better feeling. But you need to practice this. By practicing you can go from 100% bar to 80% bar in turbulent air and get the same good feeling.
Performance is getting worse when you apply brakes when you are flying XC. For most wings the best glide ratio is at the trimspeed. For some gliders the best glide ratio is even when adding a little speedbar. For all gliders you loose almost no glide ratio by applying 50% speedbar. But if you apply just a little brake, your glide ratio will be worse. When you buy your self a new wing, you are looking for the best performance, so why destroy that performance by flying around with brake applied? We recommend to look for the best performance that you can achieve with the wing you have, today! The glide ratio is defined as Lift over Drag or L/D. In XC flying all we can work on is reducing the drag. The lift is pretty constant. Applying brakes gives you more drag. Less brakes gives less drag.
The risk of using brakes is that your glider will be closer to stall or spin. If you are flying in turbulence because of thermals, wind shear, vortex, wind gradient or similar, you may get to stall or spin your glider with the same amount of brakes you fly with in laminar air. If you are flying an old glider, the trimming may be wrong and the porosity of the glider may be bad. These are also factors that increase the danger of stall or spin to your glider when using brakes.
Recovery of an unintentional spin is is to release your brakes total. Even a little brake will keep the glider spinning. If you are used to fly around with a little brake pressure, it is not unlikely that you will have more tendency to keep your glider spinning.
SIV- courses is good to get to know your minimum speed on your glider. You should not practice this anywhere else. What you should practice is to let you wing fly with good speed. You get better performance and you will have less danger for stall and spin.
Using the brakes in XC flying, is to induce the roll pendulum when turning. We only apply it on the inside to get the roll. If you use brake on the outer side, you need to use more on the inside, and you get closer to spin your glider. When launching your glider you should be prepared to use the brakes to counteract any diving forward in the pitch movement. In the flight you rather use your speedbar or back raisers. And of course use your brakes to stall the glider in the landing!