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