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23
Spin
The negative spin occurs when one side of the wing is stalled while the other is still flying. This
can happen when, if flying very slowly, one brake is pulled quickly to below the seat. When the
glider starts to spin, it will turn quickly around the vertical axis, with the stalled side flying
backwards. To recover from a spin, simply release the brake on the stalled side. The glider will
immediately speed up and, most likely, suffer an asymmetric collapse. Recover as described
above. If you suspect that a spin is imminent then immediately release the inside brake. The
glider will accelerate smoothly and resume normal flight with little altitude loss.
Wingovers
Wingovers are induced by flying alternating turns; each time letting the pendulum effect increase
the bank angle.
BEWARE! The UP Meru is a agile glider, and it is quite easy to get to an excessively high
angle of bank in just a few turns. Practice wingovers gently at first, as there is a chance
of quite large collapses at high bank angles.
Also notice that a wingover flown with more than 135 degrees bank angle is classified as
illegal aerobatics in some countries!
C-riser Steering
On full bar, the Meru can be controlled also with the red ball on the rear riser. Be aware to pull the
ball only until there is a remarkable increase of the brake pressure.
If for some reason the UP Meru cannot be controlled with the brakes, for example if the brake
handle has come off the main brake line, it can be steered and landed with the rear risers. Be
aware that, when rear riser steering, the glider is a great deal more responsive to pilot input, and
the stall happens very suddenly.
Further references
Rain-induced deep stall
There are two reasons why flying with a wet wing increases the risk of deep stalling:
First reason: A paraglider flying in heavy rain will soon grow significantly heavier and thereby
undergo changes in the centre of gravity and the angle of incidence. This may lead to deep stalls.
Note that older wings will absorb more water than newer ones due to the coating on older wings
being more permeable – this means that the critical mass may be reached sooner on older wings.
Second reason has to do with the actual rain drops on the top surface – if enough large rain drops
form that the entire top surface is covered, but they don’t join together to either flow off or become
a homogeneous mass, the surface may become so rugged that the airflow separates and the
wing stalls.
This phenomenon has been observed on hang-gliders and gliders for years but only recently have
we discovered that paragliders may also be affected. It is more likely to happen with new wings
where the cloth is still highly hydrophobic and the drops thus do not penetrate but remain on the
surface.
We know from computer simulations and practical tests that this is physically possible but we also
suspect that it occurs very seldom in real life flying.
In both cases the brake line travel becomes very short and even small input may suddenly induce
an airflow separation; in some cases even a gust or a sudden thermal may change the angle of
incidence enough to cause the deep stall.
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