AT, TAT, MAT?

On Oct 13, 4:25*pm, BB wrote:
I don't understand - if you add 15 minutes, what's to stop people from
trying to come in 14 minutes and 59 seconds sooner? *Doesn't that just
shift the "minimum task time" without affecting the racing (if not,
what's the logic I'm missing)?

--Noel

I'm guilty of being too obscure. A few years ago the US experimented
with the following rule. To determine your speed for scoring, we take
(Time + 15 minutes)/distance. Time still had to be greater than
minimum time.

The effect of this change is to offset the fact that you get one fast
final glide, or equivalently one fee thermal to the top of the start
gate, per flight, and therefore remove the critical importance of
finishing close to the minimum time.

For example, suppose you fly 50 mph through the air -- top of start
gate to top of last thermal -- *and then *do a 15 minute, 100 mph
final glide on a 2:00 hour turn area task. If you fly it perfectly and
finish in two hours, you go (50 x 1.75 + *100 x 0.25 )/2 = 56.2 mph.
If you blow it and do a 2:30 flight, you go (50 x 1.25 + 100 x 0.25) /
2.5 = 55 mph * or 972 points. That is a huge difference in contest
soaring, so no wonder pilots invest in thousands of dollars of
computers.

*If you add 15 minutes to each time, though, you get scored for 50 mph
in each case! The 15 minute time addition exactly offsets the one-
glide-per-flight effect and makes it unimportant how long you stay
out, so long as you end above minium time and fly fast.

I wish I could say that this was overturned by the evil conspiracy of
flight computer manufacturers. Pilot confusion and poor salesmanship
by its advocates *did in a very pretty idea.

And I am not trying to revive it -- lost cause!

John Cochrane

The main argument against this was due to the rate = distance / time
formula being drilled into us in junior high school. Many people hated
the idea that your speed wasn't distance divided by time. Of course at
that time points were proportional to calculated speed.

Since we have now (I suspect) increased distance points to 600 and
thereby compressed scores so speed points are not necessarily pro-rata
to actual speed around the course, it might be acceptable to re-think
a form of this. While it was analytically elegant to think in terms of
the 15 minutes added in calculating speed around the course I think it
might be better to think about it in terms of how points are awarded
and leave the speed calculation alone. I realize that there are
circumstances where a slower raw speed might earn higher points than a
faster raw speed, but my recollection is that the differences are
minor and the only way this would happen is if someone took a much
longer flight than a competitor flying nearly the same speed. Making
the scoring work with the equivalent of 10 minutes added rather than
15 would likely clean up this apparent anomaly. Also, a modest
incentive not to go chase a cloud street into the next state may not
be so bad.

I would add that, while John's logic and math are absolutely correct
there is often enough going on with the weather that overrrides how
much time you do (or should) spend on course that the logic for being
just on time versus a few minutes late gets washed away like good
intentions.

Now that the government is taking John's advice and recapitalizing the
banks rather than buying their bad loans, maybe we should revisit his
soaring advice too.

My soaring season is done, so I may as well re-hash this sort of
thing.

9B