At 23:02 24 September 2019, Martin Gregorie wrote:
On Tue, 24 Sep 2019 15:30:42 -0700, waremark wrote:

And then you land out before arriving at the airfield! I cannot
understand why people ever set finish rings at a height which
isn't sufficient to ensure a comfortable arrival at the airfield.

Looks reasonable to me: just set a small finish ring, say with a
radius equal to the distance from the airfield TP to the high key point
for the run being used on that day and ring height to what the
destructors like as high key height. That should be pretty close to
putting you at the start of what amounts to a text-book approach.


Mark,

If a Competition Director is setting a finish ring too low, have a word
with them. And also remember that you are PIC, not the CD. If you
need more height to land safely because of a stronger head wind,
weaker tail wind, pressure drop, bugs, rain or general nervousness,
the finish ring does not constrain you from crossing it above the
height set by the CD. For a given ring size, the CD will re-assess the
minimum height daily based on the minimum performance of gliders
competing and the conditions.

Martin,

See the BGA and IGC competition rules to understand properly what
a finish ring is about.

BGA:

A ring of specified radius (normally, but not exceeding, 3km) around
the finish point encompassing the contest site and the landing
circuits.

When a Finish Ring is specified, a minimum altitude related to glider
performance of the lowest performance glider in task group, terrain
and obstructions should be set. Unless there are specific
obstructions, the minimum altitude should be set to allow gliders to
just pass over the ring on a normal final for direct landing in the
expected prevailing wind.

For both the finish Line and Finish Ring, a viable direct landing
option must be available to allow finishers to land ahead without
turning after crossing the line or ring. A Control point should be
utilised as necessary to ensure compliance.

IGC:

A circle of specified radius (minimum 3 km) around the Finish Point
encompassing the contest site and the landing circuits.

Finish Ring is to be regarded as the preferred finish procedure as it
allows each pilot to slow down and concentrate on the landing
procedures and other sailplanes prior to landing.

Organisers are encouraged to use a Final Turn Point to align the
sailplanes with the desired direction of finishing.


You can download some logger files from the competitions at
Lasham to see how it works in practice.

MC