Advance acoustic XI 21, Manual

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Caution: to keep good manoeuvrability make sure to fly your
XI with enough airspeed while turning in thermals – not too much
outside brake.
Tip: if a brake line breaks you can steer the XI using the C risers.
Accelerated flight
The XI has a weight–optimised line and wing design as well as very ba-
lanced pitch behaviour in bumpy air. All this retains a very good gli-
de performance with only modestly increased sink rate in accelerated
flight. 3 line levels, and the profile chosen for the XI enables the wing to
be efficiently accelerated with little expenditure of pilot energy.
The XI wing remains extremely stable even in accelerated flight.
However, paragliders operate at a lower angle of attack while flying at
their higher speeds, and the degree of stability is generally reduced.
The higher aerodynamic forces involved at higher airspeeds mean that
a collapse can be more dynamic ( see also section «Collapses» ).
When encountering severe turbulence while flying accelerated release
the speedbar fully before applying the necessary stabilising brake. The
XI’s high degree of structural stability allows it to be flown in normal-
ly turbulent air while accelerated. Active speedbar should be employed
for adjusting angle of attack under these conditions, instead of brake.
Pitch attitude disturbances can be minimised in this way, and optimal
glide performance can be maintained. See also section
«
Speed sys-
tem with SPI
»
.
§
when the angle of attack increases ( e.g. wing pitches back when en-
tering lift ), the speed bar is briefly pressed harder
§
when the angle of attack decreases ( e.g. wing pitches forward ), the
speed bar is released
Caution: even though the XI is very stable in accelerated flight
you should only use as much speedbar as you feel happy with.
Tip: make sure that brake is not applied at the same time as
speed bar, otherwise you will find yourself in the worst possible
gliding situation, without gaining any advantage.
Tip: Always choose a suitable speed for best glide taking into
account the actual headwind, sink rate ( descending air ) and ex-
pected next climb.
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