User manual

XCSoar User Manual
The method that is used is defined in the configuration settings
dialog as the field ‘Auto Mc Mode’. The default setting is ‘final
glide’.
To enable/disable Auto MacCready, use the menu
CONFIG . MacCready Auto
When Auto MacCready is enabled, the MacCready infobox dis-
plays ‘AUTO’ instead of ‘MANUAL’; and the MacCready indica-
tor in the variometer gauge displays ‘AutoMc’ instead of ‘Mc’.
The Auto MacCready methods are described in further detail be-
low.
Final glide
When above final glide altitude, the MacCready ring setting may
be increased, resulting in a higher speed to be commanded. Be-
cause the ring setting has increased, this also increases the min-
imum strength of the thermal that would be efficient to stop and
circle in.
Similarly, when below final glide altitude, the MacCready ring set-
ting my be decreased, resulting in a lower speed to be commanded.
Because the ring setting has decreased, the pilot may be prepared
to stop and circle in weaker thermals.
Auto MacCready performs this adjustment automatically and con-
tinuously. Typically it is meaningless to enable this mode before
reaching final glide altitude, or nearly so, because early in the flight
the glider will be very much below the final glide altitude and the
Auto MacCready function would then drive the MacCready ring
setting to zero.
Mc=2 VOpt=75
Mc=0 VOpt=55
Mc=1 VOpt=65
Mc=3 VOpt=85Mc=4 VOpt=95
Above final glide
Below final glide
Safety height
83