influence of the brakes on airfoil
15
Released trimmers without brakes operation
Fast flying setting.
Due to partial modification of the aerofoil with
dedicated riser system, centre of pressure of the
aerofoil is moved forward.
Released trimmers with brakes applied
Even slight brake operation (especially when fully
accelerated) will move centre of pressure backwards,
and the torque will decrease the angle of attack.
Additionally, the airflow is considerably disturbed. In
particular cases this can cause a collapse. Steering
lines operation may be necessary for corrections of
the heading, nevertheless when flying straight line
steering handles should be fully released. Otherwise
they will alter the equilibrium of the aerodynamic
forces affecting the profile.
Closed trimmers
Operating the brakes is in this configuration a typical
steering mode and does not cause any danger. Such
setting is used during launch, landing and thermalling.
The canopy is configured exactly as during the EN
tests.
center of pressure
lift
speed
sink
pitching moment
Influence of the brakes on airfoil effectiveness
when accelerated
Pilots used to classic canopies without trimmers tend
to fly “actively”, with steering lines constantly under
tension. Such piloting of a canopy with released
trimmers is totally ineffective and can even be
dangerous.
Basic rule when flying both accelerated and on
released trimmers says: steering must be smooth,
with no aggressive inputs, using no more than 25%
of the total steering range.
In case of encountering massive turbulence we
advise to close the trimmers completely and take
active control of the canopy via steering lines.
See following drawings.
