Niviuk R-BUS, User Manual

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The possibility of the R-BUS stalling during normal flight is very unlikely. It
could only happen if you are flying at a very low air speed, whilst over-
steering or performing dangerous manoeuvres in turbulent air.
To provoke a deep stall, the wing has to be slowed down to its minimum
air speed by symmetrically pulling the brake lines all the way (100%) down
until the stall point is reached and held there. The glider will first pitch
rearward and then reposition itself overhead, rocking slightly, depending on
how the manoeuvre was done. When entering a stall, remain clear-headed
and ease off the brake lines until reaching the half-way point of the total
the brake travel. The wing will then surge violently forward and could reach
a point below the pilot. It is most important to maintain brake pressure until
the glider has returned to its default overhead flying position.
To resume normal flight conditions, progressively and symmetrically
release the brake line tension to regain air speed. When the wing reaches
the overhead position, the brakes must be fully released. The wing will
then surge forward to regain full air speed. Do not brake excessively at
this moment as the wing needs to accelerate to pull away from the stall
configuration. If you have to control a possible frontal collapse, briefly pull
both brake handles down to bring the wing back up and release them
immediately while the glider is still in transition to reposition itself overhead.
Cravat
A cravat may happen after an asymmetric collapse, when the end
of the wing is trapped between the lines. Depending on the nature
of the tangle, this situation could rapidly cause the wing to spin. The
corrective manoeuvres to use are the same as those applied in case of
an asymmetric collapse: control the turn/spin by applying tension on the
opposite brake and weight shift opposite to the turn. Then locate the
stabilo line (attached to the wing tip) trapped between the other lines. This
line has a different colour and is located on the outside position of the
B-riser. Pull on this line until it is taught, as it should help undo the cravat.
If ineffective, fly down to the nearest possible landing spot, controlling the
direction with both weight shift and the use of the brake opposite to the
tangled side. Be cautious when attempting to undo a tangle while flying
near terrain or other paragliders; it may not be possible to continue on the
intended flight path.
Over-controlling
Most flying problems are caused by wrong pilot input, which then
escalates into a cascade of unwanted and unpredicted incidents. We
should note that the wrong inputs can lead to loss of control of the glider.
The R-BUS was designed to recover by itself in most cases. Do not try to
over-correct it!
Generally speaking, the reactions of the wing, which are caused by too
much input, are due to the length of time the pilot continues to over–
control the wing. You have to allow the glider to re-establish normal flying
speed and attitude after any type of incident.
4.4 FLYING WITHOUT BRAKE LINES
If, for any reason at all, the R-BUS’ brake lines become disabled in flight,
it will become necessary to pilot the wing with the D-risers and weight
shifting until landing. The D-lines steer easily because they are not under
much tension, however you will need to be careful and not handle them
too heavily in case this causes a stall or negative spin. The wing must
be flown at full speed during the landing approach, and the D-risers will
have to be pulled symmetrically all the way down shortly before contact
with the ground. This braking method is not as effective as using the
brake lines, and hence the wing will land with a higher ground speed.
4.5 LINE KNOT(S) IN FLIGHT
The best way to avoid knots and tangles is to thoroughly inspect the lines
as part of a systematic pre-flight check. If a knot is spotted during the
take off phase, immediately abort the launch sequence and stop.
If inadvertently taking off with a knotted line, the glider drift will need to