Mike Schumann wrote:

I don't share your confidence in your ability to avoid a Hawker.
Not only do you have to luck out and see him in time, but you
need to be able to tell exactly where he is going compared to
your airspace, not only if he continues on a straight path, but
also if he sees you and tries to maneuver.

I don't have as much confidence in my ability to avoid a Hawker as I
would like to have. But I do have more confidence in that than in my
ability to "dodge a bullet", or a baseball, which are the comparisons I
made in response to another poster's implication that there was little
difference between a Hawker and a bullet. There is more to it than a
comparison of numbers, but if you are going to compare the numbers then
compare all of them -- and while doing so, season it all with a bit of
common sense, and experience, to ferret out the reality with which we
must deal in the cockpit.

As far as "lucking out", I'm sure the harder I work the luckier I will
get when it comes to spotting traffic. I continue to advocate the PCAS
as one way to enhance that process, and there are others. If you run
right out and install a transponder -- and I think you should -- I will
know where you are. You won't know where I am but that apparently
doesn't bother you, so I will take care of both of us if I can.

You say you can't judge closure. Yes, it does get harder the faster
everybody is moving and the smaller is the target. I must ask you then,
how have you survived this long? Or have you? I've been assuming here
that you have some flight time. Either you and Yuliy have never seen
another aircraft in the sky or you both have been extremely fortunate
in that the other pilot, or the big-sky concept, saved you. Because,
according to each of you, the problem of judging closure is
insurmountable. Please, stay at home if that is the case for you.

If you wish to have a realistic learning process take place here (and I
hope to benefit from it) then we are going to have to deal with
specifics, and with outcomes. You know, those unintended consequence
things; those unanticipated little complications and inadequacies that
make the best planned lays go away.


The best strategy is to get and use a transponder so you never
get close to this situation.

Apparently, you know of a transponder which will erect an impenetrable
shield around your aircraft. I hadn't heard of it.

But, I hope you do get a transponder, because I'm sure it will help in
some situations. And please let us know if you gain some insight into
the other 90 % of the traffic avoidance problem, because that will still
exist. You are failing to address the other 90% when you put all your
faith in a transponder.

If we are not willing to understand the whole problem of traffic
avoidance, if we do not believe it can be done without ceding control of
our flight to another entity, which is the only way that
Universal-Transponderism by itself can work, then we have no business
getting into a cockpit. Ultimately, we are saying that our sport cannot
survive. Psychiatrists should have a field day with all of that.

As I pointed out with a comparison of numbers in my response to Yuliy,
the problem of visual traffic avoidance is substantial, but not
impossible. What it takes to make it work has already been discussed
here ad infinitum, occasionally by knowledgeable posters, but still
hasn't gotten through to some. There is no way to replace the human eye,
and the motivation to use it and all the other tools available to the
pilot, by a simple reliance on technology and central control.

So let's take it one step at a time. Explain to us, if you don't mind,
what will be the result of every glider having a working transponder. A
simple question, no?


Jack

---------------------------------------------

"588" wrote in message
m...
Yuliy Gerchikov wrote:

That's precisely the problem: exactly what volume of air do I need to
exit?
Only that volume of air (the size of your glider) through which the
traffic is about to pass. Quite small, really.


At those distances and rates of closure it is very difficult to estimate
the point of impact in 3D, especially given the extremely limited time
for decision.
Difficult? Limited? Relative to what?


No ball game that I know comes close to the order of magnitude of
parameters that we deal with here.
Then you don't know Baseball.

If you'd ever stood in the batter's box and had a good pitcher throw a
fast ball high and inside, and then compared that experience with a
high speed closure with another aircraft, you'd find that the numbers
don't really tell the story. No number can describe the actual
experience -- you just have to be there, in the game or in the cockpit.

But if you do prefer numbers, here they a at 420 kts closure with
another aircraft (708.8667 fps) from only 1/2 nm out (3038 feet) you have
a leisurely period of 4.2857 seconds which you can use to avoid impact;
compare this with the release of the baseball from the pitcher's hand at
considerably less than the nominal 60' 6" to the plate (but call it 60
feet) at 90 mph (132 fps, and 13 mph SLOWER than the fastest
recorded pitch) which gives you 0.4545 seconds until impact (hopefully
with your bat and not your head). If this gives you renewed respect for
Ted Williams (life time batting average .344) as a baseball player as well
as a fighter pilot, that's good too. Of course, we need to bat 1.000 when
it comes to traffic avoidance, but even with only 0.5 nm separation at 420
kts we have almost ten times as long as we would when standing in the
batter's box to decide what to do, and make our move.

I assume you have already found out that you can hear a powered
aircraft from the cockpit of your glider. You can hear that baseball
coming too, which adds to the fun. And, you will remember that sound also,
but only if the ball misses your head.


This is closer to dodging bullets than it
is to any ball game.
At a muzzle velocity of 860 fps, the .45 pistol bullet is traveling at
509.5458 kts, or about 21% faster than the aircraft in this example.
However, it has a diameter of 0.45 inch whereas the cross section of the
Hawker 800XP is a 2-3 meter oval, sans wings and tail. Not at all
comparable. I'll take the Hawker 800XP challenge at a half mile every time
over the .45 ACP challenge at 20 paces. YMMV. As for the baseball, at
~three inches in diameter, it's a better deal than the 230 gr FMJ, but the
Hawker 800XP is still the easiest of all to deal with, by far.

None of these three "sports" is for the indecisive, or the feint of heart.
The advantage is very definitely to the observant, the trained, and the
confidant. One must deal successfully with the numbers, and the
experience -- and it can be done.


Jack