On Jan 3, 3:31*pm, wrote:
Hi Race Fans
The proposed contest rules changes for 2009 are available at the SSA
web site *under Sailplane Racing/Rules& Process. Due to a long time in
developing some of these changes the comment period will be quite
short. Please comment to RC members by 1/7/2009. Debate on this site
will be used as grist for coming activities but is not considered
formal feedback.
Respectfully submitted
For the Rules Subcommittee
H Nixon *RC Chair

(quote) Rule 10.8.6 has been changed such that starts will only
receive distance credit for distance flown from the“front” half of a
start cylinder.

The distance of the first task leg shall be taken as the distance from
the Start
Position to the control fix at the first turnpoint, but not greater
than the distance
from the Start Point to that control fix. (end quote)

The change to rule 10.8.6 appears to be intended to discourage starts
from the back half of the start cylinder. The comment suggests that
any start from the front half will score actual distance flown.
However, it appears that pilots starting near the back boundary of the
front half may fly non scoring distance without realizing it.

Consider the following worst case: Start cylinder 5 mile radius, area
task with first control area of 30 mile radius, center of first turn
area is 40 miles from start point. This gives a minimum first leg of
5 miles.

The proposed rule states - The distance of the first task leg shall be
taken as the distance from the Start Position to the control fix at
the first turnpoint, but not greater than the distance from the Start
Point to that control fix. This means the full score area of the
start cylinder is defined by an arc drawn from the first area control
fix through the start point. If the control fix happens to be near
the center of the first turn area then the arc will intersect the
start cylinder edges close to the straight line that defines the front
half. However, if the pilot chooses to turn anywhere except on a
straight line drawn through the start point and the first control
point, the arc will intersect the start cylinder away from the front
half line. The extreme case appears to be when the first turnpoint
control fix is on the edge of the turn area at a point that is on a
tangent drawn from the start point. There are two such points.

The worse case scenario is realized when a pilot starts the task close
to the edge of the back half on the assumption he will fly to one
tangent point and, because of a change in conditions, actually flies
to the other tangent point.

In a simple graphic analysis of the defined task I estimated a
distance of over 8 miles of start cylinder circumference between the
intersections of the two extreme case arcs and the start circle. In
other words, the potential front half circumference of approx 31.4
miles is reduced to a no risk arc of approx 23.4 miles. Someone with a
greater enjoyment of math will come up with a more accurate answer.

How, with the proposed rule change, is the pilot expected to know
whether the selected start cylinder exit point will result in a
devalued first leg distance?

Andy