User manual

XCSoar User Manual

vertical motion

Airmass

Dolphin speed to fly

Block speed to fly

A conﬁguration option ‘Block speed to ﬂy’ (see Section 11.6)

can be used to specify whether dolphin or block speed to ﬂy is

used. The infobox ‘V Opt’ shows the optimum speed according

to whichever mode is selected. When connected to the Vega in-

telligent variometer, the speed command sounds are based on this

optimum speed value.

5.7 Safety heights

Three safety heights are deﬁned to provide a degree of safety mar-

gin in glide computer calculations.

The safety heights are:

Arrival height : This is the elevation above ground at which the glider is

required to arrive at for a safe landing circuit, plus some

safety margin. This value is used in ﬁnal glide calculations

as well as the determination and display of reachable land-

able ﬁelds.

Terrain clearance : This is the elevation above ground, below which any com-

puted glide path is considered to provide inadequate clear-

ance to the terrain. The terrain clearance value affects the

glide range display, and if the ﬁnal glide at any point dips

below the terrain clearance elevation above ground, a warn-

ing marker (large red cross) is drawn on the screen. If the

terrain elevation model is invalid or out of range, then the

glide range display and the terrain warning marker is dis-

abled.