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I trying to find a way to stay in a jet stream unpowered for a larger question. Is there a glider, kite or plane that flies best when in turbulent weather?

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  • $\begingroup$ aviation.stackexchange.com/questions/24420/… $\endgroup$ – user20435 Mar 26 '16 at 18:39
  • $\begingroup$ I suggest altering the title of the question, so it's clear you're asking about something that flies better in turbulence, not which one flies the best. $\endgroup$ – D. Clayton Mar 27 '16 at 20:51
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Turbulence is always a nuisance. It will require more control inputs to stay at the desired polar point, which increases drag. Also, small-scale turbulence will cause earlier transition of the boundary layer, which is important for gliders with a laminar airfoil. Powerful turbulence might even overload the airplane's structure.

Jet stream turbulence is low and only becomes noticeable at the boundaries between the fast moving air of the jet stream and calmer air above and below. To stay unpowered in the jet stream is impossible - any unpowered craft will lose altitude due to drag when moving through the air, and even a balloon will be hard to stabilize at the altitude of highest wind speed.

Even a kite is not unpowered - it needs some force acting on the line; either by an airplane flying below or by something holding the end of the line on the ground.

If you want to know what makes turbulence more bearable: Higher wing loading, lower aspect ratio and wing sweep will help. A higher wing loading means higher airspeed, so the relative speed changes from turbulence will become smaller. Both aspect ratio and sweep will reduce the lift curve slope, so changes in angle of attack will result in smaller force changes.

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    $\begingroup$ You're confused about power. A kite can be a source of power. Example. And unpowered gliders don't lose altitude when piloted skillfully in decent conditions. The force on a kite's line is not usually a source of power. $\endgroup$ – Matthew Elvey Mar 22 '16 at 20:39
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    $\begingroup$ @MatthewElvey: Just change your reference frame ... $\endgroup$ – Peter Kämpf Mar 22 '16 at 21:47
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    $\begingroup$ @MatthewElvey: Now I want to see proof for thermalling or ridge flying in the jet stream. You did notice that I was speaking strictly of flying in the jet stream, didn't you? $\endgroup$ – Peter Kämpf Mar 22 '16 at 21:49
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    $\begingroup$ OK. I was speaking of gliders in general. While this Wired article mentions gliding using a "jet stream" to go 1000 miles, it supports you, saying the plan is to "fly nearly 1,000 miles simply by using lift provided by the rising air, and speed provided by the jet stream." Anyway, I agree with your answer - Turbulence is always a nuisance in this scenario. $\endgroup$ – Matthew Elvey Mar 22 '16 at 22:10
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    $\begingroup$ @PeterKämpf, but would dynamic soaring be possible in(-and-out of) jet stream? The velocity difference is large, but I don't know whether the transition is sharp enough. $\endgroup$ – Jan Hudec Mar 28 '16 at 11:00

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