2009 Proposed US Contest Rules Changes

On Jan 7, 1:35*pm, wrote:
On Jan 7, 12:28*pm, Andy wrote:





On Jan 7, 1:04*pm, wrote:

To visualize this draw two circles on a piece of paper - one has a
radius of 5 units (this is the start cylinder). Draw the second with a
radius of 30 units, just above the first and touching at the edge.
Your diagram now looks like a simple drawing of a soccer ball sitting
on top of a baseball. This is the worst case scenario - the biggest
possible first turn area (30 mi) sitting as close as possible to the
start cylinder (somebody check me that there isn't some minimum first
leg distance in the rules that is greater than 35 miles).

Close, but you have confused the issue by using an invalid task
example. *The minimum separation between the closest points of the
start cylinder and the first turn area is 5 statute miles. *See rule
10.3.1.1.

Andy

Thanks Andy,

RTFR - I was afraid of that. I'll redo the math.

Andy- Hide quoted text -

- Show quoted text -

Okay, The new numbers for a 40 mile first leg (center to center) are
that the "safe sector" has an included angle of around 85 degrees and
a distance along the circumference of 7.5 miles. If you increase the
first leg to 70 miles the angle goes up to 120 degrees and the
periphery extends to 21 miles. Compare that to a full "front half" for
reasonably long first legs of a bit under 31 miles around the edge of
the cylinder (it's not a full half circle because it's measured as an
arc from the first turn).

Whew!

9B

On Jan 7, 3:50*pm, wrote:
Okay, *The new numbers for a 40 mile first leg (center to center) are
that the "safe sector" has an included angle of around 85 degrees and
a distance along the circumference of 7.5 miles. If you increase the
first leg to 70 miles the angle goes up to 120 degrees and the
periphery extends to 21 miles. Compare that to a full "front half" for
reasonably long first legs of a bit under 31 miles around the edge of
the cylinder (it's not a full half circle because it's measured as an
arc from the first turn).

Your angles look reasonable to me but you seem to have made the same
mistake as I did in my second post for the length of the front half
circumference. The full circumference is piD or 31.4 miles. The
length of the front half circumference is then about 15.7, and the no
risk arc is about half of that at 7.5 for the task I defined. For the
120 deg included angle of your second task the circumference should be
about (120/360)*31.4=10.5.

I wonder which flight computer software will be the first to depict
this safe start area.

Andy

On Jan 7, 3:43*pm, Andy wrote:
On Jan 7, 3:50*pm, wrote:

Okay, *The new numbers for a 40 mile first leg (center to center) are
that the "safe sector" has an included angle of around 85 degrees and
a distance along the circumference of 7.5 miles. If you increase the
first leg to 70 miles the angle goes up to 120 degrees and the
periphery extends to 21 miles. Compare that to a full "front half" for
reasonably long first legs of a bit under 31 miles around the edge of
the cylinder (it's not a full half circle because it's measured as an
arc from the first turn).

Your angles look reasonable to me but you seem to have made the same
mistake as I did in my second post for the length of the front half
circumference. *The full circumference is piD or 31.4 miles. *The
length of the front half circumference is then about 15.7, and the no
risk arc is about half of that at 7.5 for the task I defined. *For the
120 deg included angle of your second task the circumference should be
about (120/360)*31.4=10.5.

I wonder which flight computer software will be the first to depict
this safe start area.

Andy

Arrrrgh! That explains my SAT scores for sure.

So, in summary: Instead of a full front half perimeter of 15 miles you
get somewhere between 7.5 and 10.5 miles for a 30 mile turn area -
working its way up to the full semicircle again as the first turn area
gets smaller. The searchable area for a start thermal goes from nearly
80 square miles for the full cylinder to under 40 square miles for the
best case under the proposed rule to a bit over 18 square miles under
the worst case Assuming you want to keep the whole turn area available
post-start, that is. Uncertainty about where the boundaries are would
likely squeeze the field into a somewhat smaller space.

I guess your computer could show you both the safe start area and the
penalty-free portion of the first turn area should you start outside
the safe area. That might burn some CPU cycles. Gonna need one of them
ClearNavs (or Ultimate - sorry Richard).

9B

On Jan 7, 5:19*pm, wrote:

You gotta love that unitended consequences rule!

Andy

Andy-Sama and Andy-San,

Why aren't the two of you on the RC? (Or at least consultants
thereto?)

My brain hurts

2NO

On Jan 7, 3:04*pm, wrote:
I presume the thing the RC wants to avoid is
pilots starting out the top of the back of the cylinder and bombing
through start gaggles. I'm not saying it can't happen, I just haven't
seen it.

Looks like the general rc philosophy is promoting airmanship rather
than gamesmanship. I like that.

There are some interesting strawmen presented in this thread... but
surely these are only strawmen.

Even in the worst case presented, the new rule is still a significant
improvement.

See you on the grid.

-T8

On Jan 8, 8:45*am, wrote:

Even in the worst case presented, the new rule is still a significant
improvement.


Sorry, I don't agree.

If the intent of the rule change is to prevent starts from the back
half there are better ways to do it.

The rule should define the "front half" as the semicircle of the start
cylinder that has its diameter normal to the line between the start
point and the first turn point. A valid start would only be given for
an exit from the front half.

The valid start area is then fixed for all contestants regardless of
where they turn in the first area. This valid start area is easily
visualized by the contestant without needing any special computer
software.

Andy

You really think it sounds better? From the sound of it, about the
only way to know for sure that you get a good start is going to be IF
the PDA software developers (I'm one of them) make some fairly MAJOR
enhancements to their software to depict this arc on the start
cylinder for you to see. And oh by the way, this ONLY something that
is being done here in the the US. I actually thought the "start
anywhere" concept was about the simpliest thing I'd heard so far.
This new way just makes my head spin trying to visualize it let alone
trying to pull it off in the air, in a gaggle with LOTS of other
gliders, etc., etc., etc.

In the end, it sounds like you could do the bombing through from the
back of the start cylinder but did people actually do that? It seems
like it would have to be a pretty good day or perhaps a perfectly
aligned ridge or street to make doing that very profitable. So are we
adding this complexity (read more head down time) to try to keep
something from happening that just wasn't happening?

But perhaps I'm missing the simplicity of it some how.

-Mark
OA

On Jan 8, 8:45*am, wrote:
On Jan 7, 3:04*pm, wrote:

I presume the thing the RC wants to avoid is
pilots starting out the top of the back of the cylinder and bombing
through start gaggles. I'm not saying it can't happen, I just haven't
seen it.

Looks like the general rc philosophy is promoting airmanship rather
than gamesmanship. *I like that.

There are some interesting strawmen presented in this thread... but
surely these are only strawmen.

Even in the worst case presented, the new rule is still a significant
improvement.

See you on the grid.

-T8

Yes, that seems to make more sense. But just to be explicit, you mean
the line between the center of the start cylinder and the center of
the first turnpoint, right?

-OA
On Jan 8, 9:08*am, Andy wrote:
On Jan 8, 8:45*am, wrote:

Even in the worst case presented, the new rule is still a significant
improvement.

Sorry, I don't agree.

If the intent of the rule change is to prevent starts from the back
half there are better ways to do it.

The rule should define the "front half" as the semicircle of the start
cylinder that has its diameter normal to the line between the start
point and the first turn point. *A valid start would only be given for
an exit from the front half.

The valid start area is then fixed for all contestants regardless of
where they turn in the first area. *This valid start area is easily
visualized by the contestant without needing any special computer
software.

Andy

On Jan 8, 7:45*am, wrote:
On Jan 7, 3:04*pm, wrote:

Looks like the general rc philosophy is promoting airmanship rather
than gamesmanship. *I like that.

There are some interesting strawmen presented in this thread... but
surely these are only strawmen.

Even in the worst case presented, the new rule is still a significant
improvement.

I thought that the original 'start anywhere' was a big improvement in
reducing gaggling and leeching. And it was actually simpler than the
old rule. I feel like this modification dilutes the impact of that
rule change by bunching starts back into a smaller part of the
cylinder and adds complexity and uncertainty to the start process.
Pilots do try to optimize for the rules even to save a few points or
tens of points. (The last contest I flew 40 points separated 6th and
2nd place).

To the extent that a rule affects pilot actual decision-making it's
not a strawman issue. Knowing whether you are giving up a few miles of
scored distance at the start is something that pilots will act on -
just the way we all acted on the old rule that encouraged pilots to
start from the edge of the cylinder closest to the courseline. Lastly,
my experience with the start anywhere rule last year is that pilots
bombing through pre-start gaggles didn't happen so, to me, that is
more the strawman issue that needs to be proven before adding
complexity to the rules. I'd love to hear from pilots who had a
different contest experience with the 2008 rules.

9B