Dangerous situations and extreme flying
Section 07
27
Collapsing the paraglider
Asymmetric collapse
Asymmetric collapses are caused by the
stagnation point moving to the trailing edge of
the glider. A negative angle of attack makes
part of the canopy collapse and tuck under, and
the glider may plunge down, turn away or spin.
Recovery
Should an asymmetric collapse occur, counter-
brake slightly on the side of the glider that is still
inflated to stop it turning away and to stabilise it,
until the glider flies straight ahead again. With
large asymmetric collapses, it is important to
counter-steer carefully so that the glider does
not stall completely and go into a full stall.
The part of the glider which has collapsed
generally re-inflates automatically but this can
be assisted by applying light brake pressure on
the collapsed side (but not hectic “pumping”)
while counter-steering on the opposite side.
Make use of the full braking distance.
Following a very large collapse of more than
70%, the wing-tip of the collapsed side may
become trapped in the glider lines. Our tests
have shown that the TWIN RS 2 continues in
level flight surprisingly well, even with major
cravats, by counter-braking and weight-shifting
on the open side. Most cravats can be
reopened by pulling firmly on the stabilo lines.
WARNING
Counter-steering too strongly on the inflated
side of the glider can result in a stall and to
further uncontrolled flight manoeuvres
(cascade of events).
Front stall
A negative angle of attack can also cause part
or all of the leading edge of the glider to
collapse.
Recovery
The TWIN RS 2 will normally recover quickly and
automatically from a front stall, but re-inflation
can be assisted by light symmetrical brake
input. In the case of extreme front stalls across
the entire wing chord, the wing tips may move
forward making the glider form a U-shape.
Again, recovery is by light symmetrical braking
on both sides, but care must be taken that both
wing ends return to normal flight evenly.
Types of stall
When a paraglider flies through the air, a
laminar and turbulent boundary layer is created.
Extremely dangerous flight configurations can
result if the laminar boundary layer is
interrupted, with practically the entire airflow
along the top surface braking away. This
happens in particular when the angle of attack
is too great.
There are three different types of stall in
paragliding.
WARNING
Full stall and spin are manoeuvres which can
be fatal if recovery is not correct. These
manoeuvres should therefore be avoided.
However, it is important to learn how to
recognise the indications that a glider is
about to stall so that you can take immediate
action to prevent it.
Deep stall
Paragliders can go into a deep stall for a variety
of reasons: brake lines too short (no slack), old
or damaged glider material which therefore has
increased level of permeability, altered trim/line
length and changes to profile characteristics
caused by moisture (e.g. flying in rain).
Paragliders have a particular tendency to stall if
the wing-loading is too low.
In a deep stall, the airflow from the front
reduces and the glider goes into a stable flight
attitude without forward momentum. The
paraglider sinks almost vertically at 4-5m/s
and there is noticeably less flight noise.
Recovery
Remain in an upright position and push the A-
and B-risers in the direction you are flying, so as
to shorten them by 5-10cm.
If you have a speed system, you can also use it
to accelerate, so that the glider goes into a
normal flying position from the deep stall.
After you have landed, the glider and the length
of the lines must be checked.
