Advance acoustic EPSILON 8 23, User Manual

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Speed system with SPI
The EPSILON 8 has a speed system with a Speed-Performance-
Indicator (SPI), which reads off against 3 positions on the backs of the
risers. The red markers on the speed system enable a precise speed
bar position to be set to suit the in-flight situation. Best gliding to the
next thermal needs an on-going choice of speed to fly, depending on
the current values of headwind, expected next climb rate , and the ra-
te of sink.
Each of the EPSILON 8 SPI positions has an icon with a value for
headwind, expected climb and sink rate. These indicated positions are
effective for only one of their three values, taken in isolation – conside-
red by itself. This means that either the headwind, or the expected ra-
te of climb, or the sink rate applies to that position. The SPI principle is
based on the simple (using headwind and sink) and the extended (in-
cluding expected climb rate) McReady Speed-To-Fly theory.
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