At 01:48 28 July 2007, Marc Ramsey wrote:
BB wrote:
In my opinion the clock should stop as soon as the
pilot enters the
cylinder. We shouldn't have pilots in the finish cylinder
still
racing.


You haven't met enough contest pilots. If the rules
change in this
way, pilots will aim to finish one mile out, 50 feet,
90 knots and
then float in to the landing, european-style.

Applying an appropriate penalty for finishing below
the Minimum Finish
Height would eliminate that behavior. I was actually
surprised to find
that the SSA competition rules provide no guidelines
as to how to
penalize pilots who don't make it into the finish cylinder.
Given the
difficulties of knowing precisely how high one is finishing,
missing by
50 or so feet shouldn't result in a huge penalty, but
it should also
never be beneficial to intentionally finish low...

Marc

DISCLAIMER: I understand under the new rules speed
points are no longer allocated pro-rata so as to create
bit more spread at the top of the scoresheet. My math
may, therefore, be a bit off.

The worst case scenario for making marginal final glide
decisions is on a short task where a pilot is climbing
slowly trying to make it up to final glide altitude.
The slow climb takes up lots of minutes per foot gained
and every minute drags down your speed relatively more
on shorter tasks.

So, say you are climbing at 2 knots. It will cost you
about 4 points for every hundred feet you climb, or
about 40 points to go from a white-knuckle 2-knot glide
to 0' at the finish up to a 2-knot glide to a 1000'
AGL arrival. For a 4-hour task the 4 points per 1000'
drops to 2 points per 1000'.

You could imagine a penalty structure that looks something
like: 8 points per hundred feet divided by the minimum
task time (or the winners time, or your time). This
eliminates most of the incentive to cut a last thermal
short since it is in the pilot's interest to keep climbing
if he thinks there is any chance he will be under the
minimum finish height and he is achieveing a climb
rate of 2 knots or more.

If you're climbing in your final thermal at less than
2 knots you are looking at a dicey glide no matter
what, and probably are contemplating a rolling finish.
It's not clear to me that a penalty structure built
around slower than 2 knot climb rate would do any good
- plus the penalties start to get kind of large (e.g.
16 points per 100 feet if you pick 1 knot as the climb
rate).

With the penalty structure I've described, if you finish
at 500' below the minimum finish height (so you are
at most 500' AGL) and actually fly to more or less
a full pattern it would take about 2.5-3 minutes to
get from the edge of a 1-mile cylinder to a full stop.
This is based on looking at a couple of my contest
finishes at Parowan where the runway is pretty long
and they were asking us to roll all the way to the
end. Guess what? The penalty as described above would
work out to the equivalent of an additional 2.5 minutes,
so the worst case scenario for a low flying finish,
would be no worse than taking the time to landing and
stopping. If you just barely miss the minimum height
you are a lot better off.

In terms of coming to a screeching halt in the middle
of the runway on a rolling finish - it's worth 2-5
points in my estimation. You need to weigh that against
all the other safety considerations and potential penalties
that might be imposed of you were really ver-the-top
about it. Plus the ill-will from your crew when they
have to schlep your glider halfway across the airport.

9B