Windtech zephyr-2 - Manual (Page 13)

13
-- spiral dive
The Spiral dive is performed by starting a series of 360 degrees turns, gradually pulling one brake
harder and harder and weight shifting into the turn. Pull more inside brake, and weight shift hard-
er, for a faster spiral dive but be careful not to stall one side and enter a spin in this way. Ease off
on the inside brake, and weight-shift less hard, to regain level flight. Like this, the pilot can con-
trol the bank angle and the sink rate of the glider in the Spiral dive. Always remember that whilst
in the Spiral dive you are drifting with the wind, and it is very easy to become disorientated.
This manoeuvre is not approved for bank angles higher than 60 º. At this upper limit the sink
rate of the canopy is approximately 10 m/s and the overload is equal to 2G's.
For bank angles higher than 60 degrees the sink rate can achieve 20 m/s but the greater overload
(High gravitational forces - G's) can cause eyesight and equilibrium problems, and cause some
people to 'black out' (faint), which consequently can make the manoeuvre extremely dangerous.
To recover from a spiral dive, the inner brake must be progressively and slowly released, until
the canopy assumes normal flight, and angle of bank, again. A good rule of thumb is to use the
same number of 360-degree turns as you did on entry on exit to give a safe and progressive
pullout. If you release hands up from a tight spiral dive you will experience a big surge followed
by a dive. (In turbulent air this can result in a collapse.) The ZENITH has been tested for this
but it is advisable to learn the correct exit method, i.e. progressively release the inside brake.
-- b stall
The B-line stall is a real stall even though the wing appears to be flying above your head the
laminar airflow over the wing is completely lost. During B-Stall, the canopy falls perpendic-
ularly to the ground (straight down, but drifting with the wind) at a sink rate of 5 to 12 m/s,
with an angle of attack of 90 degrees.
To enter a B-Stall, it is necessary to sit upright in your harness, reach up with the brakes still
in your hands (preferably with the toggles around your wrists) & securely clutch each B ris-
ers in each hand at the top near the Maillons Rapides (quick links). To enter the B-line stall,
pull down symmetrically on the B risers. (About 40 cm)
The force initially is quite hard (up to about 15cm) but for the last part the force required to
pull down is less. Keep your weight centred in the harness, and keep the risers held at a sym-
metric level to each other. The more B riser pulled the faster the decent rate, but the glider
can become unstable with a very deep B-line.
To return the glider to normal flight conditions:
Ease up the B-risers SYMMETRICALLY for 50% (25-cm of B-line still held) holding some pressure,
then symmetrically completely and rapidly release them. If necessary, control the surging forward
of the canopy by gently braking when the glider is in front of you. What you are trying to achieve
is to not shock-load the glider by an immediate release from a deep B-line, whilst at the time not
easing off too slowly and risking a deep stall in turbulent conditions. Releasing the B-lines from
a deep B-line position works fine (& if unsure whilst attempting the manoeuvre simply release