"Chris OCallaghan" wrote in message
om...
Flying head down is never necessary. The center of the finish cylinder is
almost always close to some visible marker on the airport. If it isn't, I
ask
the CD to move it so it is. My software beeps when I cross the boundary of
the
cylinder, does yours? Finally, I only glance at the computer once in a
while to
see if I'm falling below glide slope, which I'd also be doing with a 50 foot
gate. But then again, I'm not anal about finishing at precisely 500 feet...

I don't agree. When you approach a cylinder, you are aiming at its
center. I haven't seen a computer program that optimizes the point on
the cycliner you should be aiming at given current position and
altitude and interpolates your desired finish height to that point.

I'm not a mathematician, but I think you'll find that the point you should be
aiming for on the cylinder is on the line from your current position to the
center of the cylinder. Since, as far as I know, your computer is guiding you
towards the center of the cylinder from your current position, then you will
cross that optimal point.

Instead you are looking down as the distance clicks off, and checking
your altitude to make sure that you don't fall slightly short.

I'm not worried about falling slightly short, since I'm nearly always 500 feet
or more above the minimum finish altitude. Frankly, if your computer can't help
you navigate to the desired height at the edge of the cylinder, yell at the
designer, or get a new instrument or software. This isn't rocket science.

BTW, if you look carefully at SSA contest rules 10.9.3, it states quite clearly
that a finish is recorded when you enter the 3 dimensional cylinder. It does
not say you have to enter at the edge, you can also enter through the bottom.
What this means is that even if you cross the edge of the cylinder at lower than
the minimum height, as long as you can pull up and get a single fix within the
cylinder, you've got a finish.

Now, some buttheads somewhere will no doubt start coming in below the cylinder
and pulling up through the center, figuring this will give them a speed
advantage. It won't, since while you finish time is recorded where you enter
the cylinder, your finish distance only goes to the edge.

As noted in earlier threads this means more heads down and more
variations in traffic height and speed, all converging on a much
smaller area (the optimum point on the cylinder).

If everyone is coming from the same final turnpoint, then they will all converge
on pretty much the same point, whether using a finish gate or a cylinder. When
everyone is not coming from the same final turnpoint (i.e. an MAT), everyone
still converges on pretty much the same point with a finish gate, but they do
not converge with a cylinder.

Again, the advantage of a finish cylinder is that those people who have
sufficient energy (and don't feel the need to make low pass), end up overhead
the airport well over 500 feet, at a comfortable speed, with plenty of time to
assess the traffic situation, watch out for those on marginal glides, go through
their checklist, etc. This has worked very well at every contest I've flown in
that used a finish cylinder. The only recent contest where I've felt
stressed/hurried during finishes, was one where a few traditionalists browbeat
the CD into using a GPS finish gate.

Be careful when citing book and passage from the FARs. I know for a
fact that you don't follow some rules (none of us do) as scrupulously
as you are applying them in this case. I can find some gray in 91.119.
You'll be hard pressed to find any in 91.155.

The original quote from your message was:

As for the FARs, aircraft regularly take off and land withn 500
feet of people, structures, and other aircraft at commercial airports.
This is by necessity.

And my point was, yes indeed, this happens, and it's perfectly legal according
to 9.119.

Virtue: the behavior we demand of others, but excuse the lack of in
ourselves.

The only virtue that I request of others on this group is that they actually
read and consider what is said...

Marc