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Atis 4 M

Sicherheitsklasse 4
Atis 4 M

Instability rating

Safety class 1 Safety class 2 Safety class 3 Safety class 4 Safety class 5
asymmetric collapse
course change
forward pitching
height loss
sink velocity
G-Force
Frontal collapse
course change
Speed (Recovery)
height loss
sink velocity
Spiral dives
G-Force
Sink velocity after 720°
Maximum sink velocity
Behaviour on brake release
course change after spiral dive exit
Height loss during recovery
Safety class 4
Pilot skill requirements:
Pilots should be able to recognise the onset of instability and be able to prevent or minimise glider reactions through immediate and precise pilot inputs.
Advanced piloting skills and regular flight practice necessary.

Glider characteristics

Launch preparations: easy
launch characteristics: balanced, climbs constantly, no guidance necessary, good feedback during inflation, moderate braking required, control check simple, low takeoff speed
asymmetric collapse: canopy colllapses at high angle to leading edge, high dynamics, total course change 270-360°, (4), very fast course change rate, marked forward pitching 60-75°, (4), high height loss 40-49 m, (3), high sink velocity 20-24 m/s, (3), G-Force 2,5- 2,9 G, (2)
Frontal collapse: canopy collapses with high total collapse aera, moderate pitch backwards 30-45°, marked pitch forwards 45-60°, moderate dynamics, course change <90°, (2), variable recovery behaviour, at times immediate, at times delayed, automatic recovery, (3), usually symmetric recovery, immediate return to normal airspeed, moderate height loss 30-39 m, (2), low sink velocity 10-14 m/s, (1)
Spiral dives: moderate sink velocity increase, Low G-Force 3,0- 3,5 G, (1), Sink velocity after 720° <18 m/s, (3), Moderate maximum sink velocity < 18 m/s, (2), sink velocity increase < 6 m/s on brake release, (2), Course change 180-360° after spiral exit, (2), moderate height loss during recovery 30-60 m, (2)
B-Stall: normal force required, moderate pitch backwards 15-30°, low pitch forwards <15°, stable sink phase, no tendency to deform, delayed return to normal airspeed < 3 s, 8-10 m/s, height loss on recovery 20-40 m
big ears: simple initiation, stable flight phase, immediate automatic recovery, Vsink unaccelerated 3-3,5 m/s, Vsink accelerated 4-4,5 m/s, Vunaccelerated 3-5 km/h less than trimspeed, Vaccelerated 5-8 km/h faster than trimspeed
Steering behaviour: balanced to agile, 65 cm brake travel range, very noticable brake pressure increasse, Late stall point, easily identifiable

Notes

en:
Launch preparations:
Sky's Atis 4 follows practiced design principles and does not use any plastic rods in the
canopy. The risers split into 5 and connect to a complete set of sheathed lines.
Sorting is easy, but the canopy mid-point is unfortunately not marked.

Launch characteristic:
Sky's Atis 4 does not always inflate homogeneously, and climbs occasionally at an angle – maybe this is a result of the missing plastic rods. The canopy climbs quickly and needs a good jab on the brakes to stabilise at the zenith.

Asymmetric Collapse:
Sky Paraglider's Atis 4 reacts quite differently. The canopy generally looses a lot of its
wing area on a collapse which results in a very rapid turn. This increased twist danger was
also accompanied with large pitch forward dives. To determine if this marked dynamic
behavior could also lead to further complications such as cravats, the manoeuvre was
repeated 10 times by our test pilots. These repeat tests indicated that the initial dynamic
reactions then rapidly died down, and recovery was within the normal 50 meters height
loss range for its class. Nevertheless, the initial dynamics and increased twist danger must
be viewed critically.

Front collapses:
Sky Paraglider's Atis 4 recovers with relatively low height loss for an LTF-B
glider. Again, this canopy opens first in the middle, with the wingtip inflation being delayed.
On a few very massive 100% front stalls the canopy did form a short front horseshoe.

Spiral Dive:
Sky Paraglider's Atis 4 is well behaved in spiral dives. Moderate sink velocities, no strong
acceleration surges on exiting and rapid recovery to normal flight.

B-Stall:
Sky Paraglider's Atis 4 recovers slowly on exit and care should
be taken to apply no brake during this recovery phase.

Big Ears:
Very easy,wingtips stable,no flapping, good sink velocity.

Rating

Safety class 4

This class of paraglider reacts demandingly to one or more of the following manoeuvres: frontal collapse, asymmetric collapse or spiral dive.
Demandingly means that the above manoeuvres result in marked dynamic reactions from the glider and/or large height losses.

Advanced piloting skills which need to be regularly practised, together with good personal reaction times are required to safely fly this class of gliders. Basic recovery techniques for ending a manoeuvre are not sufficient to maintain control, reduce height loss to a minimum and prevent subsequent critical reactions. Pilots should be able to recognise the onset of the above manoeuvres and be able to prevent or minimise their effects through immediate and precise pilot inputs.

Additional experience such as regular ground handling and SIV training is required to safely fly gliders of this class. Special training or pilot skills which exceed standard training may be required for the safe performance of emergency descent techniques. Gliders of this Safety Class are not suitable for beginners, irregular flyers or low-airtime pilots.