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Old Apr 26, 2004, 03:20 PM
hang4 is offline
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Joined Apr 2004
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Well gentleman, i am new here and new to RC planes, but let me say this and take it for what it is worth to you, hope it helps. I'll preface this by saying I spent years flying a hang glider so you know what that means. Ridge or mountain soaring is fun, but nothing compares to finding the blue lift (thermals). Most hang glider pilots eventually get a vario (variometer) to detect thermals with. Like an altimeter except it tells you about the air you are in ...how fast you are being lifted or sinking, by a beeping noise. Now if someone were good in electronics and could build one in micro minature size and put in a RC glider that would send back just the audio to a set of headphones, man what a revolution it would make in RC gliders. But anyway, thermals are really hard to locate. It does take time, knowledge and a lot of looking. As some of the others have stated here...the main thing is to watch and be aware of conditions and your surroundings. One of the easiest things that I didn't see mentioned to look for and you can do this before you even leave your house....look at the clouds. If you see those big white puffy cotton ball clouds, and they are all over the sky, the thermals are cooking. That was the first thing we would look for when hang gliding. They are caused by rising thermals. You can still have thermals without them but they are a sure sign of an unstable atmosphere which is what you really want when thermaling. Another thing to look for at the site is the color of the area around you. As i'm sure you know dark colors absorb heat quicker an better that lighter area... But remember it is all relative. You can be in or near a field that is green and have area's that have darker green grass because of water or fertilizer whatever. The darker areas will produce the better and more consistant thermals. Look for anything..a road, a building roof any of these things will produce thermals first. For those who don't know what a thermal looks like...if you could see one....It is simply a bubble of air that is warmer than the surrounding air. It has surface tension just like water. As a surface heats the bubble of air builds until the surface tension will not hold it there any longer, that is in dead calm conditions. If a little breeze comes along it will break loose and rise sooner. So, in dead calm conditions, circle and look for your thermals directly above those darker areas. If a slight breeze of any kind is present circle just downwind from the dark area. When the thermal breaks loose it will drift with the wind. As the thermal rises it cools at the top of the bubble so as you rise with it try not to climb quite as fast as the thermal. At the very top of the thermal is the coldest air found. So it is sinking and moving to the outside of the thermal. If you get in that area you will still technically be in the thermal but it will be all sinking air. Not only that but as it sinks it can be quite turbulent. Your inside wing will be in warm air trying to rise and the outside wing in cooler air sinking. Not a good attitude for a hang glider or thermaling plane.
Well i think i have run on enough. Hope this is helpful to someone.
As I said I am just learning about flying RC's but I have tons of experience on riding thermals and soaring hang gliders. So, I don't believe the technique's of finding and riding the air is any different. If I can answer any question about that part, please feel free to ask.

Bill
Hang4
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