Collapses - Advance Bibeta 4 Betriebshandbuch

Info: The higher airspeed while flying with the trimmers open
results in a higher internal wing pressure. This increases the
brake loading.
Tip: We recommend that you fly with closed trimmers while
thermaling. You will benefit from better wing stability, better
handling and a better climb rate (lower minimum sink rate).
Tip: Be careful not to use brake while accelerated. There is
no advantage, and you will find yourself in the worst possible
gliding situation. First close the trimmers – this will give the
wing more stability - then you can use the brakes.

Collapses

Asymmetric collapse
The BIBETA 4 is notable for its very solid and stiff canopy. With an
active flying technique in normal conditions collapses should be more
or less completely avoidable.
If, however, the glider should suffer a greater-than-50% asymmetric
collapse at trim speed the reaction will only be a slight turning ten-
dency, and track can be maintained without problem by means of
light braking. Under normal conditions the wing will open by itself.
Because of the higher forces associated with higher airspeed the gli-
der will react to an asymmetric collapse a little more vigorously at full
accelerated speed. The turning behaviour of the wing will be a little
bit more dynamic, but is easily controlled. Basically, flight direction
should be maintained by careful use of brake in the case of an asym-
metric collapse, then the closed side opened by pumping its brake to
increase the pressure in the wing. This helps the wing to open. Brake
inputs on the open side should be done carefully so as not to stall the
wing.
Poorly flown wingovers can make the wing tips fold in and cause a
cravat. Because of the high drag that they produce at the wingtip cra-
vats can cause a strong rotation moment (=spiralling). Oppose this
desire to rotate with careful use of opposite brake. Then clear the cra-
vat by means of the orange stabilo line.
Front Collapse
After a spontaneous or A-riser-generated front collapse normal air-
flow will break down. Reopening occurs quickly and by itself.
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