164
edits
Icaro Laminar 13 MRX: Difference between revisions
Jump to navigation
Jump to search
→Analysis of the 'Tuck out of the blue' video: Summary
| Line 265: | Line 265: | ||
# At t=3:24s the downward rotation comes to a brief stoppage (see right speed bar in front of the background; you have to look very closely; frame by frame analysis!) I do not yet have an explanation for this behavior. Immediately afterward, however, a much more pronounced pitch-down occurs (pilot is still on the very left; VG rope is still blown out to the right). | # At t=3:24s the downward rotation comes to a brief stoppage (see right speed bar in front of the background; you have to look very closely; frame by frame analysis!) I do not yet have an explanation for this behavior. Immediately afterward, however, a much more pronounced pitch-down occurs (pilot is still on the very left; VG rope is still blown out to the right). | ||
# t=4:12s: The yawing has stopped (VG rope is centered again). The main suspension begins to become slack (first visible at the top of the hang strap). The arms are already slightly pushed-out. The lateral pilot deflection remains unchanged to the left. This situation corresponds to point 4 in the diagram. The nose of the hang glider is not yet pointing exactly vertically downwards. | # t=4:12s: The yawing has stopped (VG rope is centered again). The main suspension begins to become slack (first visible at the top of the hang strap). The arms are already slightly pushed-out. The lateral pilot deflection remains unchanged to the left. This situation corresponds to point 4 in the diagram. The nose of the hang glider is not yet pointing exactly vertically downwards. | ||
# t=4:15s: Jesper is still on the far left. His arms start pushing | # t=4:15s: Jesper is still on the far left. His arms start pushing out. It would be important to know whether he has actively pushed-out or whether the control bar has only moved forward without his intervention and how the bar pressure has changed in direction and strength. In this phase there is no slowing down of the rotation of the wing observable (in contrast to the tuck of the Sensor). It looks rather similar to the tuck of the U2. | ||
# Then, due to the rear center of gravity position (fully stretched arms), an extremely fast rotation begins. Jesper drifts from the sideways deflected position to the center. The right hand no longer rests relaxed on the control bar ( | # Then, due to the rear center of gravity position (fully stretched arms), an extremely fast rotation begins. Jesper drifts from the sideways deflected position to the center. The right hand no longer rests relaxed on the control bar (Is this an indication that he has pushed-out deliberately?). | ||
# t=5:08s: At this point, the harness/legs fall symmetrically into the rear wires. The negative lift forces are now only transferred to the pilot via the rear lower wires and the hands at the control bar. The nose of the hang glider points vertically downwards. | # t=5:08s: At this point, the harness/legs fall symmetrically into the rear wires. The negative lift forces are now only transferred to the pilot via the rear lower wires and the hands at the control bar. The nose of the hang glider points vertically downwards. | ||
# t=4:18s to 5:18s: Continuous increase of the negative dihedral (increasing negative air force). | # t=4:18s to 5:18s: Continuous increase of the negative dihedral (increasing negative air force). | ||
| Line 276: | Line 276: | ||
<div style="clear:both"></div> | <div style="clear:both"></div> | ||
[[File:Tuck initiation; Definition and characterization of the individual phases.jpg|left|thumb|800px|Tuck initiation; Definition and characterization of the individual phases]] | [[File:Tuck initiation; Definition and characterization of the individual phases.jpg|left|thumb|800px|Tuck initiation due to unpredictable events (gust and turbulence); Definition and characterization of the individual phases]] | ||
<div style="clear:both"></div> | <div style="clear:both"></div> | ||
<br> | <br> | ||
Could Jesper have avoided the tuck?<br> | Could Jesper have avoided the tuck?<br> | ||
Yes, | Yes, of course!<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). Admittedly, the time window for pulling-in is very | 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 short (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. ;-) | ||
<br> | <br> | ||
=== Impact of gusts on pitch-stability === | ==== Why all this theoretical crap? So how can I avoid a tuck in practice? ==== | ||
Well, if things are completely out of control (i.e. a situation arises that you didn't expect and/or scares you to death), simply apply the golden rule of hang gliding:<br> | |||
'''Shift the center of gravity as far forward as possible.''' | |||
In most cases, the problem will have solved itself by then. | |||
This requires the following actions: | |||
#'''Pull in''' as fast and as much as you can (without thinking too much - you don't have that time). | |||
#Be prepared to pull in hard to '''counteract the force of the control bar'''. | |||
#'''Prevent''' the '''control bar''' from '''moving forward''' by itself under all circumstances. This is extremely important! | |||
#As soon as the hang glider is flying stabilized again, '''wait a short time''' just to be on the safe side. | |||
#Then '''gently recover''' from the dive by letting the control bar move forward slowly. | |||
#Don't forget to start thinking again. | |||
That's all! | |||
The above applies to unpredictable and sudden events. For planned actions such as the intended flying of whip stalls, acro, etc., however, a lot of thought should be given beforehand. Therefore, a little '''theoretical knowledge can't hurt'''.<br> | |||
<br> | |||
===Impact of gusts on pitch-stability=== | |||
--- TBD --- | --- TBD --- | ||