Contest Scoring Formula Breakdown

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!

I will take a shot at it.

The best way for me to see this is to try it on a very simplified
contest flight.

So let’s try a 1 hour task. With a Start Gate at a maximum of 7000
feet and the finish gate at a minimum of 1000 feet. Lift is a
constant 250 ft/min.

Of course you will want to start as high as possible which will be
7000 feet.

I am going to use a hypothetical glider to keep the number simple.
Lets say your best speed is 60 MPH at a 250 ft/min descent.

#1 So from your start i.e. your 1st thermal you can lose 6000 feet to
put you at 1000 feet AGL. At 250ft/min this will take 24 minutes and
you will glide 24 miles. At this point you pick up another 250 ft/min
thermal and climb to 5500 ft. this takes another 18 minutes so you
have a total of 42 minutes on course. You then glide for 18 minutes
back to the finish line taking another 18 minutes to finish right at
1000 feet. So you have been on course for exactly 1 hour and have
covered 42 miles.
Your speed is 42 miles per hour.

#2 so, the same day but you decide to stay on course a bit longer. So,
on the 2nd thermal instead of climbing to 5500 feet you climb to 7000
feet. And fly some extra distance with extra the altitude. So it takes
you 24 minutes to climb to 7000 feet and you glide 24 miles to the
finish. This gives you a time on course of 72 minutes and distance of
48 miles for a speed of 48/1.2 = 40 MPH.

#3 let’s say you decide to take another thermal from the last example.
So at the 72 minute mark you hit another thermal and climb to 7000
feet this adds another 24 minutes, but of course you can glide for
another 24 minutes. So this gives you a time on course of 72+24+24 =
120 minutes and a distance of 72 miles. So your speed is 72 / 2 = 36
mph.

The reasoning that the speed gets slow the longer you stay out is that
you were given the 1st thermal. Try calculating this as if the maximum
start gate was 1000 feet.

#1 you climb to 7000 feet taking 24 minutes. You glide for 24
minutes. You climb for 6 minutes and glide for 6 minutes to the
finish. You are still 1 hr and have flown 30 miles for 30 MPH
average.

#2 you climb to 7000 feet taking 24 minutes, you glide for 24 minutes
you climb for 12 minutes and glide for 12 minutes. You time is 72
minutes and your distance is 36 miles.
Your speed is 36 / 1.2 = 30 MPH.

#3 You climb to 7000 feet and glide 24 miles for 48 minutes you climb
again to 7000 feet and glide another 24 minutes. As you can see it is
taking you 48 minutes for 24 miles. So a third thermal will take
another 48 minutes so you total time on course is 48* 3 Thermals = 144
minutes. Your distance is 24*3 = 72 miles. So your Speed is 72 / 2.4
hrs = 30 MPH.

So this demonstrates that since we start at the top of the 1st thermal
under consistent conditions it is advantages to come in as close to
the minimum time as you can.

Your course in reality changing conditions can change what is the best
strategy; however I hope this answers your question.

Brian

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

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

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

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

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

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


Put another way - you should add 10 minutes on top of the 2 minutes
per mile, not instead of it. For very long final legs add a bit more
than 10 minutes.

Andy

On Dec 17, 9:07*am, Andy wrote:
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

Put another way - you should add 10 minutes on top of the 2 minutes
per mile, not instead of it. For very long final legs add a bit more
than 10 minutes.

Andy

Sounds reasonable. The 2x rule of thumb was from DJ a couple of years
ago
and works pretty well for sports class. However, on my personal best
flight in sports
class I muffed up the finish time by not computing my target finish
time early
in the flight when I still had brain cells available to carry the hour
(3:45 task time).
The 10 minute buffer might have just about saved me the early finish.

-- Matt