Schempp-Hirth Flugzeugbau Ventus-3T Sport, Руководство по эксплуатации самолета, Страница: 100 / 177

SCHEMPP-HIRTH FLUGZEUGBAU GmbH, KIRCHHEIM/TECK
Ventus-3T „Sport“ FLIGHT MANUAL
April 2018 CS 22
Revision – 4.5.9.1
4.5.9 Flying at low temperatures
When flying at temperatures below 0° C (32° F), as in wave or during the winter
months, it is possible that the usual ease and smoothness of the control circuits is
reduced. It must therefore be ensured that all control elements are free from
moisture so that there is no danger of them freezing solid. This applies especially
to the airbrakes.
From experience gained to date it has been found beneficial to cover the mating
surfaces of the airbrakes with "Vaseline" along their full length so that they cannot
freeze solid. Furthermore the control surfaces should be moved frequently.
When flying with water ballast, observe the instructions given in section 4.5.7.
Warning:
For the preservation of a proper surface finish free from cracking, the
manufacturer strongly recommends not to fly at high altitude with
associated temperatures below -20° C ( -4° F)!
A steep descent with the airbrakes extended should only be conducted in
case of emergency. To increase the sink rate, instead of the airbrakes,
the undercarriage may also be extended.
Important note:
Experience up to date indicates the polyester coating on this powered
sailplane to become very brittle at low temperature.
Particularly when flying in wave at altitudes in excess of about 6000 m
(approx. 20000 ft), where temperatures of below -30° C ( -22° F) may occur,
the gel coat, depending on its thickness and the stressing of the aircraft
components, is prone to cracking! Initially, cracks will only appear in the
polyester coating. However, with time and changing environment, cracks can
reach the Epoxy/Carbon cloth matrix.
Cracking is clearly enhanced by steep descents from high altitudes at
associated very low temperatures.