Advance acoustic XI 21, Руководство пользователя

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Caution: In very turbulent air ADVANCE recommend trim speed
and active flying by brake lines.
Collapses
The XI features a very taut and stable canopy. With an active flying
technique in normal flying conditions, collapses can be almost com-
pletely prevented. The wing gives very precise canopy feedback and
makes it possible to sense an impending collapse early on, thus help-
ing timely pilot reaction. Should a collapse occur the wing will fold in a
predictable and progressive manner from wing tip towards the centre.
Asymmetric collapsing of the canopy
If the glider does, however, suffer a side collapse at trim speed, it will
respond to collapses of 50% or more with a slight turning tendency, al-
lowing heading to be easily held with light counter-steering. Normally,
the wing will reopen without pilot action. With an asymmetric collapse
in accelerated flight the wing will react more impulsively because of the
higher forces associated with higher airspeed. The turning behaviour
caused by a collapse at full speed is more dynamic, but can be well
controlled.
If a collapse is slow to reopen, a deep but fast pull on the closed side
brake will help. It is important to completely release the brake again
to let the glider keep its flying speed. Be careful with the brake on the
open side, and only apply enough to keep straight – so as not to stall
the wing.
Poorly flown wingovers can cause a wingtip to fold inwards from the
side, causing it to catch in the lines and create a cravat. Due to the
high drag they produce cravats can lead to strong rotation ( spiralling ).
Stop an increase in rotation rate by just the correct amount of out-
side brake. Then open the cravated wingtip by pulling the orange sta-
bilo line. Clearing a cravat can be also done more quickly by ‘pumping’.
The appropriate brake should be applied to 75% brake travel within a
maximum of two seconds, and then released immediately.
Caution: If you want to make an accelerated collapse during
safety training we recommend that you lead up to it slow-
ly – starting with unaccelerated and then partially accelerated
attempts.
Symmetric collapse ( frontstall )
After a spontaneous or A-riser provoked collapse the airflow breaks
away from the profile and the canopy will pitch back. The pilot swings
back underneath after a short delay. Wait, without applying brake, un-
til the wing is again above you and returns to normal flight. After a big
collapse reopening may be delayed, but do not forcibly encourage reo-
pening by the use of excessive brake, because of the risk of a fullstall.
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