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Icaro Laminar 13 MRX: Difference between revisions
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→Tuck avoidance: Sensor: add link; Analysis tuck Jesper
(→Tuck avoidance: Sensor: add link; Analysis tuck Jesper) |
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=== Tuck avoidance === | === Tuck avoidance === | ||
==== Tuck and near-tuck video examples ==== | |||
Below are links to 5 different videos in which tucks or near-tucks occur. | Below are links to 5 different videos in which tucks or near-tucks occur. | ||
Although the initial situations and the sequence of events appear to be very different, it will be shown later on that they all follow the same pattern and can therefore be avoided using the same control methods. | Although the initial situations and the sequence of events appear to be very different, it will be shown later on that they all follow the same pattern and can therefore be avoided using the same control methods. | ||
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{{#ev:youtube|https://www.youtube.com/watch?v=UMsIkAOeJ0I | 500 | inline | Extreme Hang Glider Whip Stall (Falcon)|frame}} | {{#ev:youtube|https://www.youtube.com/watch?v=UMsIkAOeJ0I | 500 | inline | Extreme Hang Glider Whip Stall (Falcon)|frame}} | ||
{{#ev:youtube|https://www.youtube.com/watch?v=Ofh0G0cohP0 | 500 | inline | Hang glider Tuck and in air collapse Tolmin Slovenia (Jesper)|frame|start=0&end=7&loop=1}} | {{#ev:youtube|https://www.youtube.com/watch?v=Ofh0G0cohP0 | 500 | inline | Hang glider Tuck and in air collapse Tolmin Slovenia (Jesper)|frame|start=0&end=7&loop=1}} | ||
<br> | <br> | ||
==== Analysis of the Sensor video ==== | |||
Firstly, the analysis of the Sensor video (''tumbling a hang glider''): | Firstly, the analysis of the Sensor video (''tumbling a hang glider''): | ||
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https://forum.hanggliding.org/viewtopic.php?p=150334#p150334 <br> | https://forum.hanggliding.org/viewtopic.php?p=150334#p150334 <br> | ||
Also read his following posts in this thread. The last one ends with the sentence:<br> | Also read his following posts in this thread. The last one ends with the sentence:<br> | ||
''"Im pretty sure if i were on the basetube and just put hte bar to my knees i would have just stopped at "s---"''<br> | ''"Im pretty sure if i were on the basetube and just put hte bar to my knees i would have just stopped at "s---"''<br> | ||
How true. | How true. | ||
<br> | <br> | ||
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The initiation of the tucks or near-tucks in the other videos can also be subdivided into the 4 phases. The individual phases are just more or less pronounced. | The initiation of the tucks or near-tucks in the other videos can also be subdivided into the 4 phases. The individual phases are just more or less pronounced. | ||
<br><br> | |||
==== Analysis of the U2 video ==== | |||
In the U2 video (''Hang Glide Reserve Deployment''), the initial state of the tuck initiation is at a significantly higher angle of attack compared to the Sensor due to its flight attitude (nose high) at the onset of the stall (point 1). | In the U2 video (''Hang Glide Reserve Deployment''), the initial state of the tuck initiation is at a significantly higher angle of attack compared to the Sensor due to its flight attitude (nose high) at the onset of the stall (point 1). | ||
In addition, the pilot pulls-in more, which results in a very negative moment (point 2). The diagram of the U2 clearly shows that phase 1 is much more dominant compared to the Sensor. The area under the moment curve is huge due to both the range of the angle of attack and the more negative moment (max. pulled-in). | In addition, the pilot pulls-in more, which results in a very negative moment (point 2). The diagram of the U2 clearly shows that phase 1 is much more dominant compared to the Sensor. The area under the moment curve is huge due to both the range of the angle of attack and the more negative moment (max. pulled-in). | ||
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<div style="clear:both"></div> | <div style="clear:both"></div> | ||
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==== Analysis of the Falcon video ==== | |||
In the Falcon video (''Extreme Hang Glider Whip Stall'') you can see a pilot who is only a passenger of his own hang glider most of the time. Due to the excessively high towing speed, he is hanging paralysed in his harness until he releases the tow rope or the weak link breaks. Due to the overspeed, the hang glider then pitches up to an almost vertical attitude. In terms of flight attitude, this is really the worst position. | In the Falcon video (''Extreme Hang Glider Whip Stall'') you can see a pilot who is only a passenger of his own hang glider most of the time. Due to the excessively high towing speed, he is hanging paralysed in his harness until he releases the tow rope or the weak link breaks. Due to the overspeed, the hang glider then pitches up to an almost vertical attitude. In terms of flight attitude, this is really the worst position. | ||
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<div style="clear:both"></div> | <div style="clear:both"></div> | ||
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==== Analysis of the Laminar video ==== | |||
The fact that '''nuances can make the difference between tuck and recovery''' can also be seen in the Laminar video (''Whip Stall in Laminar14MRX''). Phase 1 corresponds somewhat to that in the U2 diagram, phase 2 to the Sensor and phase 3 more to the Falcon. For this reason, a separate Laminar diagram has been omitted. | The fact that '''nuances can make the difference between tuck and recovery''' can also be seen in the Laminar video (''Whip Stall in Laminar14MRX''). Phase 1 corresponds somewhat to that in the U2 diagram, phase 2 to the Sensor and phase 3 more to the Falcon. For this reason, a separate Laminar diagram has been omitted. | ||
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<div style="clear:both"></div> | <div style="clear:both"></div> | ||
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==== Analysis of the 'Tuck out of the blue' video ==== | |||
The fifth video (Hang glider Tuck and in air collapse Tolmin Slovenia) is a very rare documentation of a tuck out of the blue. In contrast to the previous videos, in which the tuck initiation is predictable (either due to the high angle of attack and/or the pilot's deliberate control input in phase 0), here the hang glider tucks suddenly out of a normal gliding attitude. | The fifth video (Hang glider Tuck and in air collapse Tolmin Slovenia) is a very rare documentation of a tuck out of the blue. In contrast to the previous videos, in which the tuck initiation is predictable (either due to the high angle of attack and/or the pilot's deliberate control input in phase 0), here the hang glider tucks suddenly out of a normal gliding attitude. | ||
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Yes, that is possible!<br> | Yes, that is possible!<br> | ||
Either he could have flown a little faster (pulled-in slightly). This would have made him less susceptible to gusts or, ideally, he should have been in the maximum possible forward pilot position at point 5 in the diagram (at the very latest at α=-4°; CM=0 | Either he could have flown a little faster (pulled-in slightly). This would have made him less susceptible to gusts or, ideally, he should have been in the maximum possible forward pilot position at point 5 in the diagram (at the very latest at α=-4°; CM=0). Admittedly, the time window for pulling-in is very small (approx. 1s). It is therefore important to be mentally prepared in advance and to have “automated” control reflexes. You can practise this with ''FlightGear'', for example. ;-) | ||
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=== Impact of gusts on pitch-stability === | |||
--- TBD --- | |||