Polar And Glider - LXNAV LX80XX User Manual

Operating Modes Version 6.03, May 2017

5.1.12 Polar and Glider*

Use this dialogue to enter glider polar and other properties of glider. As default polar a
standard class glider is selected.
Polars for most modern gliders are already prepared. Press the LIST button and a dialogue
with a list of all available gliders will be shown.
Select the required glider using the PAGE selector knob and press the SELECT button. All
glider data will be copied from the chosen polar. You may quickly check the best glider ratio
and minimum sink rate to see if the polar data matches the glider performance. You can
modify the polar by changing coefficients a, b and c. A polar is defined as a quadratic
equation with the parameters a, b, and c. Use the LX-Polar program to calculate coefficients
a, b and c for a given glider's polar. The program requires at least three sink points entered
at selected speeds (e.g.: 100 km/h, 130 km/h, and 150 km/h). The program will calculate
the values of a, b and c, which should be noted and entered into the system.
You can download program free of charge from www.lxnav.com
Weights must be entered if user enters ballast in kilograms. There are three weights to
enter. Ref.weight corresponds to the Ref.load value and represents the value at which
the polar was measured or recalculated. Reference weight or reference wing load value will
be automatically recalculated based on Wing area property. Max.weight is the maximum
take-off weight allowed for a glider. It is not used in the calculation; it is just a reminder to
the pilot of the maximum take-off weight. Empty weight is weight of the glider without
pilot and ballast. The overload factor is calculated as:
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