Imagine you’re safely aloft, but in need of lift as the one thing you have in your favor – altitude – gradually disappears. First, determine the position and height you will need at the end of your search if it fails. Now estimate how far the remainder will allow you to glide, descending, during the search – and don’t forget to factor in the wind! Then examine the area for possibilities, using every kind of information (clouds, terrain features, previous experience), and try to devise the most efficient sequence for linking together possible locations of lift in a long, exploratory glide.
Weigh your priorities before deciding what kind of search pattern to fly. If low altitude is not an immediate problem, you can start with the most promising area and save the least promising for last, but other particulars might complicate this issue.
Proximity to the surface is a crucial factor in developing an effective search pattern. When you’re well above the low ground, but near high terrain, start at the highest promising hilltops within reach and work your way down to successively lower ones, saving the bottomland for last. (If instead you searched high above a low hill and found nothing, you might then be too low to reach the higher ground.) Later, even while gliding across the flats toward a possible landing, continue to ‘connect the dots’ of potential lift sources in the most logical manner, all the way down to arrival at pattern height. If you find nothing and have to land, at least you’ll know you did all you could. What could be more frustrating than landing before you wanted to and then seeing a cumulus form above the thermal source you failed to inspect? (This strategy of flying searching above highest terrain within reach functions in reverse, as well. At the beginning of a mountain flight, the quickest way to the top often consists of moving from each momentary climb to the next highest place nearby.)
When wind is a major factor, it can influence decision-making in more than one way. With several thousand feet of altitude to use, it might be best to search downwind early, while you’re still high enough to get back. If you are already low, maybe sniff in the windward direction first, so that if you find nothing a return the other way will be easy. Staying upwind also will allow more liberty to search on either side while running downwind to the landing site.
Imagine strong thermals rising through a strong wind. We have two types of current colliding at right angles, so there might be significant turbulence and thermals may not have consistent texture or shape. When wind distorts them, a subtle variation of the uniform circle may help to maintain position within their cores. Flying a broad, flat turn on the windward side of each circle and a tight, steep turn on the lee side can offset that tendency to drift downwind from the best lift. This is essentially the same maneuver that power pilots refer to as ‘turns around a point’. Of course such a complicationcould be overdone, and the thermal lost altogether. Experiment with this, and return to simpler techniques of they seem more effective.
Where thermals are rising steadily from a stationary source, but the wind is strong, a tentative figure-eight is at times useful. It eliminates the weaker, downwind half of each circle by turning into the wind each time you’re headed across the wind, and is safer than full circles near a hill. This is simply a shortened version of standard ridge soaring technique, and will sometimes be the only method that works. (Figure-eights are valuable in rotor and wave as well, for the same reasons.) With multiple sailplanes in close proximity, however, changing directions in this way may not be sufficiently safe…
However you work this thermal, if you know or suspect there’s wave overhead, leave your thermal from the highest point you can reach and fly directly into the wind. Then, with a little luck (and if you hold your tongue just right) you might achieve one of soaring’s most special miracles: THERMALING INTO WAVE!
When you expect a thermal or you know there is one and hope to use it, fly as lightly as possible on the controls and feel for any perceivable sense of dynamic. Merely wandering can prove counterproductive, for it allows lift to push an undirected sailplane away and into sink.
Instead, try some form of logical search pattern that will keep you oriented so you can return to any particular point within the search area. Experience will help in choosing what sort of search pattern to employ. A very broad circle may suffice, but a square, rectangle, or figure eight might work better.
It’s often best to try the highest ground you can reach first, even if it seems less promising than some lower spot. (If you flew over lower ground first and failed to find lift you might then be too low to try a higher place.) As altitude is lost in the search, that’s when you should explore progressively lower areas. Of course you must plan any search pattern in mountainous country so that, if nothing is found, you’ll still have sufficient altitude to glide out to a safe landing…
Sloping terrain offers nothing if you’re below it. (The same is true of thermal hunting, of course. Those black rocks may be hot enough to cook on, but if you are not above them, the lift they generate will be above you – and out of immediate reach.) The terrain beneath you is what counts!
Even in the absence of strong wind, the day’s first lift normally will be found above some kind of sloping ground. If sun and wind are coming from approximately the same direction, it should be easy to locate. But if they oppose each other at odd angles, lift may be so broken or intermittent that simply staying up is a great challenge. But whether it amounts to weak thermals enhancing ridge lift or vice versa, you can usually expect either to strengthen as the sun rises in the sky. Then, aside from any squalls or frontal-related activity, expect both thermals and wind to weaken as evening approaches.
