Nielsen-Kellerman ClearNav - Manual (Page 59)

NK ClearNav Manual • Version 0.5 • July 3, 2008
Page 59 of 86
number to display most of the time as you “outsmart” the airmass.
Example Calculation:
As you cruise along on this glide the ClearNav is logging the difference between the current
measured sink rate and the theoretical sink rate at the current speed from the polar. For
example, for a single reading if the measured sink rate is 250 ft/minute and the polar gives a
sink rate of 300 ft/min at the current speed then the netto value of +50 ft/min is recorded for
this data point – indicating that the airmass is rising at 50 ft/min. The many numbers logged
during this glide are averaged and the average is displayed.
•
Average Climb
This is the average climb rate since take‐off – or since the start of the task. The number is
automatically reset when the task is started because the data measured before the start of the
task is likely to be very different from the data measured after the start of the task. Many pilots
will find that this number is much lower than their best guess at their average climb rate. This
number is theoretically a great number to use as a recommended MacCready setting.
•
Average Glide Netto
This is the average netto climb or sink achieved in all glides since take‐off – or since the start of
the task. The number is automatically reset when the task is started because the data
measured before the start of the task (while trying for minimum sink rather than cross‐country
speed) is likely to be very different from the data measured after the start of the task. The term
“netto” indicates that the sink rate at the current speed from glider’s polar is added to the raw
vario number so that the displayed number shows what the airmass is doing rather than the
combination of airmass motion and glider sink rate. A value of zero indicates that the glides
have (on average) been done in still air. A positive value indicates that the glides have been
done (on average) in rising air. A negative number indicates that the glides have been done (on
average) in sinking air. Theoretically, you will slow down in lift and speed up in sink and should
be able to get a positive number to display most of the time as you “outsmart” the airmass.
To access the Vario Display Options Window:
Press the Focus button once or twice until the Numeric Information Area at the bottom of the
screen is in focus (not the Selection Box).
Press the Left and Right buttons to put the focus on the Vario Window.