How to pick the time for launch
So there you are. At the takeoff. Your body is ready for flying, your mind is full of plans for the day. Full of expectations. Full of goals to achieve. You have planned for this day. Weather forecasts have been taken together with your favorite breakfast to be maximum prepared. You have prepared your glider, it is heaped together with your harness and the other equipment. There are nice cumulus clouds over your head and nice cycles of thermal coming in. Still nobody launches but going around and chatting about everything else than flying. "Why don't they launch?" you think, "I don't want to to be the test subject today, again!".
This is a common dilemma. Should I wait for other pilots to launch and maybe loose airtime, sitting on the ground? Or should I just go first and take the risk to bomb out because I missed the cycle? This is about to find the best moment to launch.
"It looks good! You go first!" is a phrase often heard. Most as a joke, but it describes very well what we really want. Get the other pilots out in the air to show you where to go, and if the conditions are favorable for getting a climb right in front of takeoff. If we manage to do so, we can forget the dilemma and just be the follower.
Make up your own mind about the conditions. Work on your skill to determinate the best time for launching. In that way you become more independent and can choose for your self. Many times the other pilots on takeoff play a conservative game. Too conservative! And you become the victim of this game, loosing your airtime. Loosing valuable time to get the extra kilometers. In most situations you will take off too late, if it is for the other pilots to decide. If the opposite is the case, well, then you get your test subject already out there!
Take off early! In competition flying, the first tree rules are all the same: "Take off early"! This is applicable to freeflying, as well. Once the conditions are good enough to let you stay in the air, you are in better position if you are in the air, than on the ground. Usually the day improves during the first hours, and many pilots choose to be on the ground during this first part of the day. If you are in the air, you get a better feeling of the air and how the conditions develops. You get to know the day, and are more prepared to pick the right moment to start your XC. You may actually be able to take the first climb that can bring you to the cloudbase. This is the first step on your XC. From there you have to take the next choise: "Should I stay, or should I go, now"! But if you are still on the ground you are still far from that choise.
Lifted condensation level will raise during the first part of the day. This is what we call cloudbase, or the maximum height that is available for us. Some days the LCL is too low for taking of early. Then it may be smart to wait and see if it raises enough to launch. What too low means, depends on which takeoff you are at. You need to know the place to determinate this. Remember that in some days there may be a low inversion over the valley, far lower than the takeoff. On these days you need to get your first thermal from above the inversion layer. Then you are dependent of the LCL to get enough workspace to avoid going under the inversion layer. If you drop under the inversion layer, you will be stuck and may have to wait for hours to get back over the mountain and to reach cloudbase.
Temperature difference from landing to takeoff gives you an idea how stable or unstable the day is. So if you got the opportunity to measure both, it is favorable. If you go up early, there may be no difference and you need to wait for the sun to warm up the ground before thermals starts. If there is enough wind to do some soaring, and it is not forcasted to drop, you may as well wait in the air. Be aware of what happen on the way to takeoff. Maybe cumuluses started to form, even if you did not measure any temperature difference? The sun can do a lot during the time it takes you to go to takeoff. Many places there are weather stations at the takeoff. Maybe it wold be nice to have them on the landing to see how it is like when you are at the takeoff?
Observ the conditions at all times. On your way to takeoff, while you unpack your equipment, when you are smalltalking to your pilotfriends. Always have one eye at the conditions. Observ the wind, thermal cycles, watch the flag down in the valley, monitor the water if you see any, look for ripples on it. Look for wind in the leaves on the trees below you. Look for birds. They often come to show you that the thermal activity has started. Do not only use your eyes. Use your ears, too. Often when the day starts, you can hear new sounds. A river, traffic or other things with sound that need help by the rising air to reach your ears. On the other end of the day, if you are too late at the takeoff, you may hear sounds from the mountain above takeoff, and you feel the air is getting colder. Then it is too late. You got the cold air coming down and you will be standing in wind from the back. And it will not get better before the next day.
Prepare your equipment immediately when you come to the takeoff. Do the linecheck and clip into you harness and mushroom your glider. Cover it from the sun and you are ready to strap in in no time. Some days the window for launching is very limited. These days you may loose your opportunity to fly, if you don't do this preparation as soon as you get to the takeoff.
Weak cycles. If the thermal cycles are weak you need to time the launch so you start in the beginning of one cycle. You may only got one chance to get the necessary meters above takeoff. If you make this timing wrong, and launch at the end of the cycle, you may end up low, before you get the next one. Sometime when it is weak, it is necessary to fly away from the takeoff, to try to catch a thermal somewhere else. Maybe there is a clue somewhere that gives you an idea where to go? Sometimes it is better to take this risk, than to stand on the takeoff the whole day, waiting for stronger cycles.
Strong cycles. With stronger thermals it is also nice to have the correct timing in the beginning of the cycle. But since stronger thermals also means more frequent thermals, you can do the timing wrong, and still make it to cloudbase. If the thermal is very strong, it may even be better to launch after the thermal has dropped in strength. Better than being dragged on the takeoff.
Strong wind. If you want to make the really long XC-flight, you may want to fly downwind in strong wind. This gives you the advantage that you are drifting with the wind, even when thermalling, and your groundspeed and glideratio on glide is more favorable for big XC. But launching may be tricky, since the takeoff very often suffer under wind compression that gives even more wind at takeoff. And the first thermals, that are not so strong, usually comes in addition to the wind, giving you more wind than allows you to launch in a safe way. Then you better wait for the stronger thermals to start. They will leave the ground more out from the takeoff and they will block the wind so you will have less wind to launch in. Under such conditions, it is smart not to take the thermal closest to the mountain, but search out for a stronger one. This will give you opportunity to climb a little, before drifting back to takeoff. You will then have gained so much height, that you may search out again for the next strong thermal. Allowing you to reach the next at higher altitude than the previous one. Repeat this until you are in cloudbase before you let your self go away from the takeoff mountain . Avoid drifting too far over the takeoff mountain before you are in cloudbase. You may be stucked in the compression over the top, and not be able to have enough groundspeed to get out in the front of the mountain again. Be careful flying in strong wind. Many accidents happens under influence of strong wind. And flying in strong wind with thermal activity is totally different from flying in strong laminar wind by the coast.