Contest Scoring Formula Breakdown

On Dec 15, 10:18*am, mattm wrote:
On Dec 14, 8:04*am, Andy wrote:





On Dec 12, 11:29*am, wrote:

On Dec 12, 1:05*pm, T8 wrote:

On Dec 12, 10:08*am, Scott Alexander
wrote:

I'm still confused on why it is that if the minimum time of a contest
day is 2:30, then you should plan to be back no later than 2:40. *Can
anyone explain the breakdown of the formula to me?

Thanks!

It's because all the climbing you do before the start is "free" (i.e.
not time on task). *The higher the gate, the shorter the task, the
greater incentive there is to finish at (but not under!) minimum
time. *Thought experiment: what's the best strategy for a 15 minute
minimum task with a 6000' gate?

This guideline gets tossed if there's an opportunity to go faster at
the end of the day due to ridges, cloud streets, etc. *Example: Day 4
at R2 this year. *Winners were an hour or more over minimum time. *It
also makes sense to stay out on course longer if you've made some bone
head move early on that slowed you down. *The longer you fly on a day
like that (without further mistakes) the more you dilute your goof.

-Evan Ludeman / T8

Evan has it right.
Very simply, any time you think you can improve your speed, keep
going.
This is very commonly true on short tasks where most of us start too
soon.
It is also true if CD rightly has not made the start rediculously high
because free climb is a smaller proportion of the flight.
On the other hand, weak day, slow speeds, day not improving, try to
finish just over time. Undertime is to be avoided because you leave
achievable miles unused.
More important- concentrate on good climbs and selection of flight
path.
Good Luck
UH

In addition to the above logic for being as close to min time as
possible, the extra 10 minutes is a rule of thumb "buffer" to keep you
from being under time. This is because most pilots and glide computers
can't guess arrival time that precisely and the "penalty" for being
under time is much steeper than the "penalty" for being over time.
Getting marked to min time is essentially averaging in zero mph for
the time you are under versus amortizing the "free" initial climb over
a longer time on course if you are over. The longer the final leg the
more buffer you should add because the longer you will have to make up
minutes if the final leg is stronger the initial estimate. *There is
almost nothing worse than watching your estimated time on task
steadily drop below min time on final glide, knowing that there is
nothing you can do about once you make the final turn.

At one time (2004?) there was a rule to eliminate this mathematical
anomaly in the formula by adding 15 minutes to everyone's time on
course for scoring purposes. 15 min is an estimate of the time
required for the initial climb so the resulting speed for the entire
race more closely approximates the sustained cross-country speed. Many
pilots didn't like it because in some cases a pilot with a higher raw
speed due to flying a short task could score lower than a pilot who
flew a longer task and a lower raw speed. You have to bend your brain
a bit to understand how this could be true - and then bend it some
more to come up with a thoughtful perspective about which pilot really
flew a better race.

9B

And one last note gleaned from a contest flying camp. *Instead of
adding
a 10 minute buffer, just estimate 2 miles per minute (120mph) for
final
glide. *You're not likely to fly that fast, especially in sports class
or
on a dry day in FAI classes, so you won't come in under time. *E.g.,
you're 20 miles out, so figure 10 minutes. *If you're 15 minutes under
time,
then you should fly further and find more lift.

-- Matt

It's not a bad rule of thumb, but it doesn't account for differences
in starting height, winds and any expectations about lift encountered
along the way. This is what glide computers do. The 10 minute buffer
is intended to account for the computer being wrong for any of a host
of reasons. Dolphining and finding bands of lift (or sink) are the
main drivers of the computer being off. That's what the 10 minutes is
for. So if your computer tells you you can get home right on min time,
you keep on flying until it says you'll be 10 minutes over. 10 minutes
is what you add to your estimated time to get home.

9B

9B