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Old December 18th 10, 09:09 PM posted to rec.aviation.soaring
Andrzej Kobus
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Default USA 2010 Competition Rules Committee Minutes Posted

On Dec 18, 3:58*pm, "kirk.stant" wrote:
On Dec 18, 9:49*am, John Cochrane
wrote:









Is it maybe time to retire the separate concepts of speed points and
distance points? IN particular, wouldn't it be better if outlanders
got credit for speed too?


As far as i can see, the only reason not to is the practical one that
in the old days there was no evidence of exactly when an outlanding
was made, making it impossible to reliably calculate speed to that
point.


In these days of GPS traces that is no longer true.


It's 01:40 here and I only gave this a few minute's thought, but I
can't immedately see major unfairness in the following proposal:


raw points = S * (D - L/2)


Whe


D = the scoring distance as defined by the task rules
L = the distance from the landing point to the finish line (0 for
finishers)
S = speed achieved over the scoring distance


The raw points could be simply kept as is and totaled up over the
contest (this would devalue bad days in a natural way), or the maximum
could be scaled to 1000 or some lesser value according to existing day
devaluation rules.


This seems to me to have the following nice characteristics:


- if you fly the same distance as someone else then it's better to do
it faster, regardless of whether you both complete the task or both
land out at the same place.


- if you achieve the same speed as someone else then it's better to
maintain that speed over a longer distance.


- speeds tend to have a fairly small spread on a given day (except for
those who spend a long time on a low save), so the preferred method to
more points is more distance.


- the penalty for landing out just short of the airfield is very
small, reducing the incentive to try to stretch and just scrape over
the fence.


- once you stop making forward progress it's better to land out
promptly than to waste a lot of time scratching at low level. This may
be true even in the case of an eventual save. (I'd have to run the
figures)


- if faced with a long, slow, skinny, final glide it may in fact be
better to fly quickly to a good outlanding area that you can reach
easily. (once again I'd have to run the figures)


- distance flown away from home counts for half, distance towards home
counts for 1.5x. If you're going to land after 100 miles it's better
to do it out and return than straight out.


What do you think? Totally stupid? Perverse and unsafe incentives I
didn't notice? Too complex?


I'm certainly prepared to debate whether that "2" is the right value.
For sure the number needs to be bigger than 1, otherwise a straight
out task is worth zero.


I also wondered about a slight variation:


raw points = (D^2 - (L^2)/2) / T


Where T is the flight time.


This is less different than it first appears. S = D/T, so the first
version can also be given as:


raw points = (D/T) * (D - L/2) *= *(D^2 - DL/2) / T


This is the same in the event of a straight out flight but the
alternative version penalises landouts near home relatively much less
after a long flight than after a short one.


The main problem I see is that "speed to landout" can encourage you to
dive to the dirt, and needs a major calculation to figure out when
that's the right thing to do. At least my landouts seem to be preceded
by a half hour of grinding away in half knot lift at 1000 feet. (And
too many of my contest flights are interrupted by a half hour of
griding away in half knot lift!). A pilot gets a lot more points in
this system if he gives up and lands right away.


Maybe the answer then that the scoring program should evaluate every
possible "end of the flight" and give you the one with the most
points. For example, 80 mph to 90 miles is better than the eventual 50
mph to 95 miles where you eventually land. But that seems pretty
complicated, and still leaves some hard strategizing for the pilot on
when it's worth stopping to work weak lift.


This is worth thinking about. Our points formulas are horribly
complex, but every good idea for simplfying them hits a brick wall on
how do you treat landouts vs. speed.


Maybe zero points for landout, but you can drop your worst day?


Well, the other problem is that we've built up a lot of experience
with the current system, so radical changes are dangerous.


John Cochrane


How about scoring a finish under min time as a landout at the finish
line? *No arguing, it's the same as blowing your final glide and
landing short. *That would create some incentive to stay out on course
longer!

Kirk
66


That would be real good for the fastest pilot of the day who came 1
min early.