Bubble Thermal
Last week we discussed a technique to find a missed thermal. You thought you would be the thermal master by not falling-out on your next tow. Beware, sometimes when you turn around to find the thermal, it's really gone. Why? It's time to learn about the bubble thermal.
Your friend who turned while you proceeded for a few more seconds is now climbing well behind you. You turn around which by now is probably in the sink, increasing your altitude separation, now underneath him, you are not climbing. He found the bubble and you did not, I have seen this happen while being within 100ft.
Thermals are not always these great columns of rising air that are explained in your basic books. They can be like bubbles. I always imagined the thermals as a column and within these columns are bubbles, almost like blowing bubbles in the pool. This may not be accurate but it was easier to visualize for me.
This visualization helps explain how someone 100ft above you can be climbing while you are not. It also reaffirms the 'don't backtrack for the thermal' thought process. It may have been a bubble and even with your moving map or superhuman spacial orientation, you won't find the thermal again.
In previous articles, I talk about centering quickly this is another reason why it is important. Why it is important to feel the glider and turn in the correct direction the first time and not have to do a 270 correction. Why continually trying to center the thermal is important so you do not lose the bubble.
These overly frustrating thermals require when looking out on track for other gliders, the only ones that really matter will be the gliders that you will reach the same altitude. Deviating towards a glider that is 2000ft above you might not be worth it... Wait who am I kidding, circling gliders are like clouds. Remember Dale Bush's motto "Always follow the clouds unless they are too far off course. Then follow them anyway."
Banner Photo by Petr Kolmann
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Garret Willat holds a flight instructor rating with over 8000 hours in sailplanes. His parents have owned Sky Sailing Inc. since 1979. He started instructing the day after his 18th birthday. Since then, Garret has represented the US Junior team in 2003 and 2005. He graduated from Embry-Riddle with a bachelor's degree in Professional Aeronautics. Garret represented the US Open Class team in 2008 and 2010 and the Club Class team in 2014. Garret has won 3 US National Championships.