How does Winscore calculate finish altitude?

I don't find this to be true, Andy. Altimeters need
to be re-set primarily when landing at a destination
1000's of miles away from the takeoff location. I find
my altimeter to be surprisingly accurate when landing
at my takeoff location after a 4 hour flight. This
is true with the SN10 altineter, also.
JJ


>The issue is that the the altimeter setting is usually
>unknown at the
>time of landing but it is almost certainly different
>for the altimeter
>setting at takeoff time. The altmeter error on landing,
>if still
>using the takeoff altimeter setting, may exceed 100
>feet even if there
>is no significant weather change.
>
>Andy
>
>

> I think if you have a 'zero penalty' band pilots will
> tend to use it. I can't figure the difference between
> and 700' finish with a 200' band and a 500' finish.

Andy,

My point is that the current system encourages you (the racing pilot)
to shave the 500' limit as close as you can, but at the risk of losing
a lot if you miscalculate - or opt for a low altitude dash to a rushed
landing to minimize your losses. Plus it encourages expensive gadgets/
software (as I now realize that my SN10 will show the info I need, for
example - priced one lately?) and clock watching at the finish.

Providing an "altitude-neutral" band to finish in should remove the
incentive to aim for the bottom, since there would no longer be a
benefit to be gained, while the risk of losing a lot would be a strong
incentive to aim for the top of the finish band. The band should be
big enough to hit easily with a properly set regular altimeter (I
think 200' would work) without being so big the adjustment for
altitude becomes "gameable".

Heck, how about adding one second for every 2 feet below the top -
that works out to a 1.2 knot final climb - which wouldn't hurt you
much if you were 20 ft low, but would still encourage not finishing
199 ft low (who wants to give away time, after all).

The addition of "no racing after the finish" (i.e. if below the
bottom, the "hard deck" in fighter speak, you get your finish and
penalty right there and can forget about a straight in finish and
concentrate on making a safe low altitude landing) would additionally
discourage high risk finishes.

I know, I know, enough whining, this is pretty much beat to death -
time to start bashing 2-33s again...

Cheers,

Kirk

kirk.stant wrote:
....
> My point is that the current system encourages you (the racing pilot)
> to shave the 500' limit as close as you can, but at the risk of losing
> a lot if you miscalculate -

Kirk,

Doesn't the old fashioned system encourage you to finish at 50 ft
altitude and 70-90 knots airspeed (whatever was MC speed for your last
thermal) ? Each pilot added extra margin for their own comfort, but
the scoring encouraged them to leave no margin.

Todd Smith
3S

Andy wrote:
> On Jul 29, 4:01 pm, Marc Ramsey <m...@ranlogREMOVE.com> wrote:
>> The SN10 also does a pretty good job at this (mine is better, of
>> course), what's the issue?
>>
>
>
> The issue is that the the altimeter setting is usually unknown at the
> time of landing but it is almost certainly different for the altimeter
> setting at takeoff time. The altmeter error on landing, if still
> using the takeoff altimeter setting, may exceed 100 feet even if there
> is no significant weather change.

SSA competition rules explicitly state that the finish altitude is
determined based on the most favorable (to the pilot) of the baselines
established at *takeoff*, as well as landing. Guy has verified that
Winscore is doing precisely that. If one leaves their glide computer at
the takeoff altimeter setting, or the glide software is able to
calculate a takeoff pressure altitude baseline and uses that to
determine the finish arrival altitude (as mine does), altimeter error is
simply not a factor...

Marc

On Jul 30, 7:21 am, John Sinclair
<REMOVE_TO_REPLY.john.sincl...@att.net> wrote:
> I don't find this to be true, Andy. Altimeters need
> to be re-set primarily when landing at a destination
> 1000's of miles away from the takeoff location.

We have an AWOS right on the airport, so I set the mechanical and 302
to this shortly before takeoff. When I check the altimeter after 4-6
hours, the change is typically 1-200' - and usually puts me lower.
Really unsettling if I'm on a marginal glide and the air looks stable
ahead.

-Tom

Tom,
You are noting the altimeter correction factor and
then applying it to the new altimeter setting, aren't
you?

If I get 29.90 from AWOS at Minden and then set it
into my altimeter and it reads 4800 feet, I must readjust
the setting to make it read field elevation (4720)
and then note the altimeter correction factor (- .1)
which I must apply to any new altimeter setting I get
in the air.
JJ

At 17:12 30 July 2007, 5z wrote:
>On Jul 30, 7:21 am, John Sinclair
> wrote:
>> I don't find this to be true, Andy. Altimeters need
>> to be re-set primarily when landing at a destination
>> 1000's of miles away from the takeoff location.
>
>We have an AWOS right on the airport, so I set the
>mechanical and 302
>to this shortly before takeoff. When I check the altimeter
>after 4-6
>hours, the change is typically 1-200' - and usually
>puts me lower.
>Really unsettling if I'm on a marginal glide and the
>air looks stable
>ahead.
>
>-Tom
>
>

On Jul 30, 2:12 pm, John Sinclair
<REMOVE_TO_REPLY.john.sincl...@att.net> wrote:
> Tom,
> You are noting the altimeter correction factor and
> then applying it to the new altimeter setting, aren't
> you?

When I set my altimeter per the Kollsman window, it reads field
elevation +/-20' so there is no correction factor needed.

In a contest, if the field elevation is 1234' MSL, and if there is a
nearby altimeter available, I'll typically see something like
1200-1250, so I just set my 500' finish to be at 1800' MSL as
indicated on the altimeter.

FYI, it's really easy to sync the Kollsman indication to match the
field elevation, but probably not something to be done outside a
repair station. :)



-Tom

At 13:54 30 July 2007, Kirk.Stant wrote:
>> I think if you have a 'zero penalty' band pilots will
>> tend to use it. I can't figure the difference between
>> and 700' finish with a 200' band and a 500' finish.
>
>Andy,
>
>My point is that the current system encourages you
>(the racing pilot)
>to shave the 500' limit as close as you can, but at
>the risk of losing
>a lot if you miscalculate - or opt for a low altitude
>dash to a rushed
>landing to minimize your losses. Plus it encourages
>expensive gadgets/
>software (as I now realize that my SN10 will show the
>info I need, for
>example - priced one lately?) and clock watching at
>the finish.
>
>Providing an 'altitude-neutral' band to finish in should
>remove the
>incentive to aim for the bottom, since there would
>no longer be a
>benefit to be gained, while the risk of losing a lot
>would be a strong
>incentive to aim for the top of the finish band. The
>band should be
>big enough to hit easily with a properly set regular
>altimeter (I
>think 200' would work) without being so big the adjustment
>for
>altitude becomes 'gameable'.
>
>Heck, how about adding one second for every 2 feet
>below the top -
>that works out to a 1.2 knot final climb - which wouldn't
>hurt you
>much if you were 20 ft low, but would still encourage
>not finishing
>199 ft low (who wants to give away time, after all).
>
>The addition of 'no racing after the finish' (i.e.
>if below the
>bottom, the 'hard deck' in fighter speak, you get your
>finish and
>penalty right there and can forget about a straight
>in finish and
>concentrate on making a safe low altitude landing)
>would additionally
>discourage high risk finishes.
>
>I know, I know, enough whining, this is pretty much
>beat to death -
>time to start bashing 2-33s again...
>
>Cheers,
>
>Kirk
>


I must be missing the point Kirk - if there is no penalty
for finishing at the bottom of the 'neutral band' then
I'd be inclined to shoot for the bottom of it to save
time. With the 30 seconds per 100' penalty band my
behavior changes - in that case I'd shoot for the top
of the penalty band but wouldn't worry too much about
a few feet of miscalculation or misjudgement. Are you
thinking of my 'penalty band' when you say 'neutral
band'? Maybe that's it.

9B

On Jul 31, 1:06 pm, Andy Blackburn <REMOVE_TO_REPLY.lear...@>
wrote:
> At 13:54 30 July 2007, Kirk.Stant wrote:
>
>
>
>
>
> >> I think if you have a 'zero penalty' band pilots will
> >> tend to use it. I can't figure the difference between
> >> and 700' finish with a 200' band and a 500' finish.
>
> >Andy,
>
> >My point is that the current system encourages you
> >(the racing pilot)
> >to shave the 500' limit as close as you can, but at
> >the risk of losing
> >a lot if you miscalculate - or opt for a low altitude
> >dash to a rushed
> >landing to minimize your losses. Plus it encourages
> >expensive gadgets/
> >software (as I now realize that my SN10 will show the
> >info I need, for
> >example - priced one lately?) and clock watching at
> >the finish.
>
> >Providing an 'altitude-neutral' band to finish in should
> >remove the
> >incentive to aim for the bottom, since there would
> >no longer be a
> >benefit to be gained, while the risk of losing a lot
> >would be a strong
> >incentive to aim for the top of the finish band. The
> >band should be
> >big enough to hit easily with a properly set regular
> >altimeter (I
> >think 200' would work) without being so big the adjustment
> >for
> >altitude becomes 'gameable'.
>
> >Heck, how about adding one second for every 2 feet
> >below the top -
> >that works out to a 1.2 knot final climb - which wouldn't
> >hurt you
> >much if you were 20 ft low, but would still encourage
> >not finishing
> >199 ft low (who wants to give away time, after all).
>
> >The addition of 'no racing after the finish' (i.e.
> >if below the
> >bottom, the 'hard deck' in fighter speak, you get your
> >finish and
> >penalty right there and can forget about a straight
> >in finish and
> >concentrate on making a safe low altitude landing)
> >would additionally
> >discourage high risk finishes.
>
> >I know, I know, enough whining, this is pretty much
> >beat to death -
> >time to start bashing 2-33s again...
>
> >Cheers,
>
> >Kirk
>
> I must be missing the point Kirk - if there is no penalty
> for finishing at the bottom of the 'neutral band' then
> I'd be inclined to shoot for the bottom of it to save
> time. With the 30 seconds per 100' penalty band my
> behavior changes - in that case I'd shoot for the top
> of the penalty band but wouldn't worry too much about
> a few feet of miscalculation or misjudgement. Are you
> thinking of my 'penalty band' when you say 'neutral
> band'? Maybe that's it.
>
> 9B- Hide quoted text -
>
> - Show quoted text -

I guess I'm not making myself very clear. I see the "neutral band" as
an area where there is no advantage anywhere in it - you get the time
it would take to climb to the top added if you finish below the top.
So you might as well climb the extra 200 ft and not risk a low finish,
but having done that, if you run into sink and finish 100' below the
top (but 100' above the bottom) you only get dinged by the time you
would have spent getting that 100 ft back. But if you push it and aim
for the bottom of the neutral band, you get time added (time it would
have taken to climb to the top), and if you miss low - then you get a
big hit (no finish or rolling finish). To me, that would encourage me
to plan my final glide to the top of the window, but not worry too
much if I'm 50 ft low when I finally cross the line. If I saw I was
getting too close to finishing at the bottom, then I could slow down
early enough or change my finish strategy.

I guess that the crucial calculation would be the climb rate used to
equalize the neutral band. A bad choice would obviously create a bias
towards finishing high or low. Better to bias towards finishing high?

And maybe 200' is too much - perhaps a 100 ft window?

I'm no mathematician, so my logic and assumptions may be false, but it
seems doable to have the rule create a "window" that we can aim for
(assuming we want to win, and are not going to climb way above the
optimum finish height).

A side note - which of the current glide computers/PDA programs figure
the final glide to the finish line, instead of to the finish point
(center of the finish circle)? I'm pretty sure my SN10 figures to the
center of the finish circle, not the actual line - Dave Nadler, if you
are reading this, could you chime in?

Kirk