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georgex έγραψε:Πολύ σημαντικό. Αλλά το κατάλαβα αφού την έπαθα.
Συγκεκριμένα σε SIV κάνω σπιράλ, μόλις το 3ο που έκανα μια και ακόμα αρχάριος, και επί της ευκαιρίας μια και ήμουν πάνω από θάλασσα λέω θα το κάνω δυνατό.![]()
Αμ δεν είχα διαβάσει στο μάνουαλ ότι το συγκεκριμένο αλεξίπτωτο κλειδώνει στο σπιράλ... Έχω μπεί του σκοτωμού, έχω αφήσει το φρένο και περιμένω να βγεί... περιμένω... περιμένω... βρε μήπως να τραβήξω λίγο το εξωτερικό φρένο? πως μου ήρθε τότε αυτή η ιδέα... οπότε βγήκα και δεν έκανα μπλούμ (ή μάλλον σπλάτς, όπως τα έντομα στο παρμπρίζ).
georgex έγραψε:Μπορεί να γίνει κάτι με όλη την ενέργεια που έχει το αλεξίπτωτο? Μήπως ένα wing-over την ώρα που πέρνει φόρα να ανέβει?
O Adrian Thomas έγραψε:There seems to be some confusion in this thread about what a lock-in means in a spiral. There are two things being discussed. 1. a glider can enter a steep spiral and rock over into a downward position with the leading edge pointing almost at the ground. Pilots often talk about this as a locked-in spiral but it is not what is being tested for (IIRC). It is not particularly dangerous except that the descent rate can be very high and the g forces can also be very high. Pilots have been known to have their arms pinned back immovable because of the g forces. If this happens and you are still holding the controls LET GO the glider will recover itself (at least every wing I have flown would). You may then have a messy surge to deal with but it is better than hanging on rigidly which could leave you in the spiral.
2. What the testers are looking for is 'Spiral Instability' this is when a glider once put into a turn continues to increase the bank angle and rate of turn even when the controls are released. This is what makes gliders fail tests - if you go into a spiral on a spirally unstable glider and release the brakes it will continue to spiral and might even tighten in. A glider with this behaviour would certainly not get a DHV 1-2 rating. I've seen Mike Kung testing for this and he does not muck about with it - very spectacular indeed, and very very thorough.
Spirals: I use spiral dives as my preferred rapid descent mode, but always, always use asymmetric (offset) spirals. These are spirals that start as a steep 360 using inside brake and weightshift to tighten the turn, but then once the glider is in a steep turn I slacken the brakes and reduce the weightshift at the same point in the 360. The result is that the turn becomes asymmetric with a wide open turn at one side, and a steep turn on the other. If you build it up enough you can end up above the glider on one side of the turn and below it on the other. (don't try this at home but reverse the direction with enough energy and you loop).
Why do I do asymmetrics and not straight spirals? Because the forces on the glider, and the G forces on me are dramatically reduced, but the descent rate is still very high. Once per 360 I am in a position that is well-designed for exiting the 360, and the steadily changing g-forces and orientation make it easier to avoid dizziness and stay aware of where you are. Speeds get very high but the glider is positive all the way round. I try to minimise brake to keep the speed up. After all the only reason for doing this stuff is to get down as fast as possible.
Fly safe,
Cheers, Adrian
Ένας μαθητής του Chris Santacrose έγραψε:On my most recent maneuver clinic (Sept/2002) with Chris Santacroce. we practiced our asymetric spirals, his words of advise to us were to "use asymetric spirals", not spiral dives !!! Thus a much safer controlled descent technique learned. No more death spirals please... learn to find the peace in the air, don't blame the new wings for your "brain farts". The new wings want to fly if you let them!
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