Note: The OptGndSpdCone accuracy depends on the wind accuracy.
When the ESS is a cylinder the distance to the ESS does not depend on the pilot altitude. On the
contrary, when the ESS is a cone the distance to the ESS depends on the altitude. Because of this, the
NAV SD provide 2 distances in 2 dierent data elds. The Dist.Cone data eld shows the distance to
the ESS at the current pilot altitude (see Figure
5.2
). As the glider glide ratio (GR) is usually positive
and nite the altitude at which the pilot reaches the ESS is dierent from the current altitude, so real
distance to the cone depends on the GR. The Dist.ConeA data eld shows the horizontal distance to the
ESS considering the expected average GR trough the remaining path (see Figure
5.2
).
Note: The expected GR is calculated considering historical data and also the wind compo-
nent at that direction.
If a pilot is ying at the polar point corresponding to value indicated in the OptSpdCone data eld it will
take him a certain time to reach the cone. There is a vertical speed (thermal speed) which allows the
pilot to climb and reach the cone in the same amount of time. This vertical speed value is shown in the
ConeVSpd data eld and corresponds to the minimum thermal speed which compensates climb instead of
ying straight to reach the cone faster.
Note: The minimum thermal speed indicated in the ConeVSpd data eld does not take in
account the wind drift. If the winds blows in the cone direction the minimum thermal speed
is lower than indicated, otherwise is higher.
56
Summary of Contents for Flymaster NAV SD
Page 1: ...User manual Version 3 0...
Page 54: ...Figure 4 42 GPS Reset 53...
