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Speed to Fly and Thermals. Wing Polar http://parapente.para2000.free.fr/wings/index.html. Compare two Wings. Travel Speed for downwind XC . South Africa Thermals. Highest temperature can be expected between 15.00 and 17.00 in a day. Means thermals are highest late in the afternoon
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Wing Polarhttp://parapente.para2000.free.fr/wings/index.html
South Africa Thermals • Highest temperature can be expected between 15.00 and 17.00 in a day. Means thermals are highest late in the afternoon • Thermals start off in the day narrow and strong and become wide and weak in the late afternoon
Thermal probability Thermal probability 1.5 km 1.5 km 8 km 8 km 15 km 15 km 0.5 m/s 0.5 m/s 20% 20% 90% 90% 99% 99% 1.0 m/s 1.0 m/s 10% 10% 60% 60% 84% 84% 2.0 m/s 2.0 m/s 5% 5% 30% 30% 52% 52% 3.0 m/s 3.0 m/s 2% 2% 10% 10% 18% 18% Chance of finding a Thermal
Distance to next Thermal Rule of thumb is that one needs 2.5 times the height of a thermal to find another one. For Dunnottar, low cloudbase days work best. 700 meters and a glide ratio of 6-7 = 4-5 km 700 meters x 2.5 = 1.8 km to the next thermal1500 meters x 2.5 = 3.8 km, just possible 3000 meters x 2.5 = 7.5 km, fly Welkom
Where to find the lift under a cloud • On a weak wind day on the sunny side • Or up wind and towards the sun. For Gauteng area, wind is predominant NW. Sun in the afternoon is shining from the NW, so look for the lift in the NW corner of a cloud
That’s all for today Mort recommends that you got your recovery organized More at http://marca.homelinux.com/ulf/skygod/s2f/s2f.html