US SSA/SRA Contest Rules Poll

I think it is simple.

Here is my language: "Your start is scored for distance and time when
and where you exit the start cylinder the last time"

As Larry points out, the issue of separating pre-start and post-start
traffic is fairly easy to solve. As one minor addition, if you do slip
back in to the cylinder, you can then start again if you stay under
for two minutes, or take your original start, but scored in the old-
fashioned way. The scoring program already knows to look for multiple
starts and take the best one. The scoring program already finds the
"start fix" so the change is not hard to program.

Previous discussions of this option at SRA meetings focused on a
different issue, highlighted in the pro/con of the poll. In no wind
the "start anywhere" option is great, it's like a start line because
all parts of the start circle are equally good. But in significant
wind, the optimal start point is at the upwind edge of the cylinder,
rather than at the wind-triangle upwind point under current rules. If
in addition, it's a crosswind or downwind, the optimal point is 90
degrees away from the courseline. Now, as currently, it's not a huge
big deal to start 30 degrees away from this optimal point, but it is a
bit worse than currently because you start and then make a sharp
course change. Still, the US RC wisely decided not to use a start
line, because in a significant crosswind it funnels all gliders to one
point in space, the upwind edge of the start line. There is some
concern that the "start anywhere" option would have this same effect.

The most important question, I think, for the poll, is how do pilots
feel about this? Are the obvious advantages of "start anywhere" on
days without much wind offset by the potential disadvantage of this
scenario? In your experience, how often is there enough cross or
downwind on the first leg that this would be a problem? The RC is
pretty good at thinking through traffic issues, but this really is a
pilot preference issue, and hearing opinions on the poll will be very
useful.

John Cochrane

The scoring program already knows to look for multiple
starts and take the best one. The scoring program already finds the
"start fix" so the change is not hard to program.

I am not so sure about that.
I had the opportunity to help scoring the Canadian Nat's.
A contestant requested to be scored on the second last start.
This gave him a small advantage due to him being 5 minutes early.
Udo

On Nov 2, 10:40 am, BB wrote:
I think it is simple.

Here is my language: "Your start is scored for distance and time when
and where you exit the start cylinder the last time"

As Larry points out, the issue of separating pre-start and post-start
traffic is fairly easy to solve. As one minor addition, if you do slip
back in to the cylinder, you can then start again if you stay under
for two minutes, or take your original start, but scored in the old-
fashioned way. The scoring program already knows to look for multiple
starts and take the best one. The scoring program already finds the
"start fix" so the change is not hard to program.

Previous discussions of this option at SRA meetings focused on a
different issue, highlighted in the pro/con of the poll. In no wind
the "start anywhere" option is great, it's like a start line because
all parts of the start circle are equally good. But in significant
wind, the optimal start point is at the upwind edge of the cylinder,
rather than at the wind-triangle upwind point under current rules. If
in addition, it's a crosswind or downwind, the optimal point is 90
degrees away from the courseline. Now, as currently, it's not a huge
big deal to start 30 degrees away from this optimal point, but it is a
bit worse than currently because you start and then make a sharp
course change. Still, the US RC wisely decided not to use a start
line, because in a significant crosswind it funnels all gliders to one
point in space, the upwind edge of the start line. There is some
concern that the "start anywhere" option would have this same effect.

The most important question, I think, for the poll, is how do pilots
feel about this? Are the obvious advantages of "start anywhere" on
days without much wind offset by the potential disadvantage of this
scenario? In your experience, how often is there enough cross or
downwind on the first leg that this would be a problem? The RC is
pretty good at thinking through traffic issues, but this really is a
pilot preference issue, and hearing opinions on the poll will be very
useful.

John Cochrane

I see the effect as somewhat different.
Now, a pilot chooses between the optimum start point based on wind
and thermal distribution relative to
shortest distance to first turn. In fact what most do is try to find
the "fast gaggle(KS, DJ etc) and get with them.

With exit point start, the tradeoff no longer exists. The pilot simply
goes to the best cloud in the windward quadrant- just like everybody
else. They then collect around the same guys, and the result is pretty
much the same.
I describe this from experience in the WGC where we saw the same
thing.
The gaggle collects at the best cloud, and tries to go 30 seconds
after the Brits!

The start method that pretty much stops all of this and drives pilots
to make "soaring starts" is the multi-point start where the fleet is
randomly divided into 3-4 groups each with their own start cylinder.
With this one, there are no big gaggles and you have to go based on
your assessment of the soaring conditions. We put this into place, but
it died due to lack of interest. It worked very well in Oz in 2001.

The biggest benefit to exit point scoring is that it makes your flight
match the result generated
by See You.
Interesting debate.
UH

On Nov 1, 8:19 am, chris wrote:

The description said something about exiting out the back, then flying
through the gaggles in the start cylinder. I don't understand this
because if you did this then by definition you pass through the start
cylinder again and then have a restart on the 2nd exit right?

On a strong day the pre-start gaggles may be much higher than the
maximum start height. It would in theory be possible to exit the
rear, perhaps by climbing through the top adjacent to the rear of the
cylinder then bump pre-start gaggles for approx 10 miles without
descending into the top of the cylinder.

Andy

The description said something about exiting out the back, then flying
through the gaggles in the start cylinder. I don't understand this
because if you did this then by definition you pass through the start
cylinder again and then have a restart on the 2nd exit right?

On a strong day the pre-start gaggles may be much higher than the
maximum start height. It would in theory be possible to exit the
rear, perhaps by climbing through the top adjacent to the rear of the
cylinder then bump pre-start gaggles for approx 10 miles without
descending into the top of the cylinder.

Andy

It is possible to have the start cylinder height above the expected
top of the lift (or cloudbase) for the day. For the most part this
worked extremely well at this years sports nats. The problem was on
the blue days when, as the thermal weakened at the top, the highest
gliders would begin to sink back down, while lower gliders would still
slowly be climbing, ending with close to 20 gliders withing 200ft of
each other. Of course, this could also happen with a start cylinder
of limited height as pilots use spoilers to keep below the top. It
also is probably not practical in the West - 18000ft of free altitude
would make for some impressive speeds, however.

Has the "start arc" been seriously considered? This is a start line
that arcs towards the turnpoints at each such that the distance to the
center of the first turn is the same no matter where you start. It
would still be advantageous to start at the upwind part of the arc,
but you wouldn't be able to get an extra ~5mi on top of that by going
through the side of a cylinder. This is somewhat more complex to set
up, but most modern flight computers have been programmed to support
it and I know its been used in Europe, although have no idea how
successful it was.

2C

Has the "start arc" been seriously considered? This is a start line
that arcs towards the turnpoints at each such that the distance to the
center of the first turn is the same no matter where you start. It
would still be advantageous to start at the upwind part of the arc,
but you wouldn't be able to get an extra ~5mi on top of that by going
through the side of a cylinder. This is somewhat more complex to set
up, but most modern flight computers have been programmed to support
it and I know its been used in Europe, although have no idea how
successful it was.

2C

While I do not have any competition experience with gliders, something
I hope to change in 2008, I have competed for many years in hang
gliding competitions. For start cylinders we use two types; the
traditional exit cylinder and an ENTRY cylinder. The entry cylinder
is a large diameter cylinder, typically centered at the first turn
point or beyond it. Lets say the first turn point is 50 miles away,
the entry cylinder could be defined as a 45 mile diameter. Your start
time is determined when you last ENTER the start cylinder. The theory
for this approach is the diameter of the cylinder allows for more
spreading out of the competitors and allows the pilot to determine
best positioning for running to the first turn point. One thing that
you have to ensure is that the diameter of the entry cylinder is large
enough to prevent pilots from flying around the back side, entering
the cylinder from behind and proceeding to first turn point. This
issue can also be addressed by making the center of the start cylinder
also your first turn point.

The ENTRY cylinder sounds similar in concept to the startline arc
mentioned above. The entry cylinder has been very successful for hang
glider and paraglider compeitions.

Ron Gleason
DG303 N303MR

On a strong day the pre-start gaggles may be much higher than the
maximum start height. It would in theory be possible to exit the
rear, perhaps by climbing through the top adjacent to the rear of the
cylinder then bump pre-start gaggles for approx 10 miles without
descending into the top of the cylinder.

Andy

If this is viewed as a problem, we simply limit the option for last-
exit start to disallow flying over the top of the cylinder. (If you do
it, you still get a start, but scored under the old formula. You still
get a score for the day, and you still can start out the top as now,
but there is no advantage to doing it.)

Again, these traffic problems are easy to solve. The big question is,
do pilots want to do it this way? Or do the potential disadvantages in
strong winds, or the "big gaggle" just moving upwind a bit, make it
better to stay with things as they are?

John Cochrane

"BB" wrote in message
oups.com:

On a strong day the pre-start gaggles may be much higher than the
maximum start height. It would in theory be possible to exit the
rear, perhaps by climbing through the top adjacent to the rear of the
cylinder then bump pre-start gaggles for approx 10 miles without
descending into the top of the cylinder.

Andy

If this is viewed as a problem, we simply limit the option for last-
exit start to disallow flying over the top of the cylinder. (If you do
it, you still get a start, but scored under the old formula. You still
get a score for the day, and you still can start out the top as now,
but there is no advantage to doing it.)

Again, these traffic problems are easy to solve. The big question is,
do pilots want to do it this way? Or do the potential disadvantages in
strong winds, or the "big gaggle" just moving upwind a bit, make it
better to stay with things as they are?

John Cochrane





I see Andy's theory as such a 'non-issue'. What Andy is describing is
exactly the same action that takes place anywhere out on course. And
per his example, the gliders are already separated out into several
thermals, lowering the glider/thermal density.



Simply allow scoring for time and distance from any "exit" from the
cylinder and you have spread out the field as much as they will be
spread out. There will still be the leechers, and some big gaggles.
But we will have mitigated the "one optimal exit point" somewhat. Any
other restriction scenarios force everyone to the "frontmost" or
"windmost" point of the cylinder and the inevitable big gaggles.



My $0.02



Larry Goddard

01 "zero one"

On Nov 4, 9:27 am, BB wrote:
On a strong day the pre-start gaggles may be much higher than the
maximum start height. It would in theory be possible to exit the
rear, perhaps by climbing through the top adjacent to the rear of the
cylinder then bump pre-start gaggles for approx 10 miles without
descending into the top of the cylinder.

Andy

If this is viewed as a problem,

John and Larry, I was not presenting this as a problem, only as an
explanation to the poster who wondered how it could be possible to use
start gaggles to advantage.

Andy