Brauniger IQ-CLASSIC Operating Instructions Manual page 17

1. Climbing in a thermal
Best glide path
Fastest arrival path
Current flight path
1.While climbing in thermals, an integrating variometer that is invisible to the user collects
the average climb value for the past 30 sec.. This climb value and the active polar determine
the optimum flying speed during the descent. (according to McCready)
For each circle, the flight direction always points precisely towards the target; at this
moment, the wind component is obtained from the difference between air speed and ground
speed. Wind conditions are thus taken into consideration for all departure elevation
calculations.
The target symbol begins to flash as soon as the pilot reaches an altitude that allows him to
reach his destination at his best glide. Simply flying off now would be extremely risky,
however, since the slightest patch of descending air mass would compel him to touch down
first. Therefore, additional altitude should be gained at least until the precalculated arrival
elevation runs from negative figures through "0" and the target symbol is on continuously.
If the climb in the thermal was good, it is now recommended that you take the path for the
fastest arrival. Speed should be increased to the point that precalculated arrival altitude is just
above 0. The McCready indicator will level off at the average climb value.
If the climb in the thermal was poor, it is up to the pilot to decide whether to gain more
altitude in order to compensate for any zones of descending air.
2. When gliding to the target, the instrument displays the precalculated arrival elevation or,
more correctly, the altitude above the McCready glide path. This figure is also equal to the
arrival altitude above the target, but this is conditional on the path to the target not containing
any rising or falling masses of air and on the existing wind remaining constant. If the pilot
were to fly for a moment at the best glide speed, the arrival altitude then displayed would be
a safety margin that he can use to the target to counteract falling masses of air or can use up
by means of an increase in speed.
Compared with previous instruments in the IQ-Comp./GPS series, we have integrated even
more sophisticated arithmetics for the calculation of the above-listed functions from March
2003. The main benefit lies in the steadier display of the precalculated arrival elevation.
In Setmode 21 an additional security height (in m for each km distance) can be set to
compensate sinking air masses during the glide path.
2. Gliding down to your destination
Altitude displayed above the McCready glide path
Altitude above the best glide path
Target
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