Hiya Eagle 1,
1) When turning, the glider is subjected to centripetal & centrifugal forces, resulting in what we experience as "G". E.g. in a coordinated turn with 60 deg. bank, the glider is subjected to 2 G. Effectively, if your gliders mass is 400 kg. the wings will now have to create 800 kg. of lift. This is exactly equivalent to flying the glider under 1 G, but with a mass of 800 kg. Now - given they fly the same speed, which of the two is gonna have the higher polar sink? Aaaahh - realisation dawns! That is the reason why the speed for minimum sink increases above the AOM value (which is for s&l) when circling in a thermal.
2) Because the loadfactor is measured perpendicular to the flightpath. Say the flightpath is 90 deg. - i.e. straight up or down. How much load will the wings need to support? None, since in a climb, the kinetic enegy of your glider is converted into potential energy, so the kinetic energy cancels the gravity out, and the wings are unloaded. The same in a dive, only the drag is what counteracts gravity. For the same reason, you'll see that e.g. the K21 will need to be pitched beyond a vertical pitch attitude on the way down to produce a vertical line, since you need a negative AoA to produce zero lift on an assymmetrical profile. The Swift & Fox don't need any such compensations, since they have a (near-)symmetrical profile.
Hope this helps - best regards,
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