"Dave Martin" wrote in message
...
At 14:18 01 May 2004, Bill Daniels wrote:

'Dave Martin' wrote in message
...

So all we need is a simple instrument that meets the
following criteria.

1. It will detect at least 40 gliders in close proximity.
2. Plus those within a 5 nautical mile range.
3. Work out their relative positions.
4. Assess the collision threat of each and every one.
5. Feed the information to the pilot of each glider
in a readable format that can be assessed within the
bat of an eyelid.
6. Develop the instrument with little financial assistance
from within the movement.
7. Ensure every glider has the equipment fitted.
8. Ensure the equipment works with very little power
consumption.
9. Ensure that the cost is no more that a launch fee.
10. Make fitting compulsary to ALL aircraft flying
in uncontrolled airspace.


The above vastly overstates the issue. It's yet one
more 'do nothing'
argument. Make the problem seem too difficult and
people will give up.

Listing the nearby gliders is very easy. You don't
need to list them by
contest ID just the number within a reasonable distance.
Those beyond 1 Km
are of little interest. You aren't interested in the
relative positions of
all gliders, only those that represent a non-zero probably
of a collision.
At any instant, out of 40 gliders, only one or two
might represent a real
hazard.

This is a very easy bit of computer programming. Devices
that do almost
exactly this are already available as consumer devices.
(FRS walkie talkies
with integral GPS ~ $150US) Only small improvements
are needed for glider
use.

Making every glider carry one is not likely or necessary
but it could become
a requirement for contest flying. Clubs with a large
fleet might decide to
install them. Most gliders fly within a local area
so local rules will
work.

This device need only work with gliders. The rest
of the aircraft fleet
will use transponders. For protection from these,
you need a transponder
too.

Bill Daniels

Bill

You are clearly a pilot in the US, with vast open skies
in which to fly.

Here in the UK our skies are crowded, we are being
squeezed by commercial ventures who need more and more
airspace
Frequently contests fly over and around other gliding
sites, pilots on cross countries select other gliding
as turn points. Local soaring is some areas can take
in can take in 10 or more other sites, plus powered
strips.

You say in addition to the anticollision device we
should also have a transponder and in the UK few glider
pilots have radio licences so they can use the ttansponder
(although this is changing). At present we do not have
the power to drive them.

At a meeting of with airtraffic controlers they were
alarmed at the thought of 40 gliders all flying in
a contest fitted with transponders, they thought it
would screw up A their computers and B their controllers
trying to make sense of 40 gliders in a thermal.

You say my argument vastly overstates the issue, I
think it is very much understated for UK flying.

These are real issues when flying cross country in
a crowded little island.

I would welcome and applaud someone who can solve the
problem but in the short term let us be realistic.


Unless everyone carries the equipment it is about as
much good as a one legged man in a butt kicking contest.
It may tell you were some gliders are but not every
one, therein lies the danger.

Enough said,

Dave

Yes I do fly in the vast empty skies of the western USA, thank goodness.
However, I'm also a pilot who has survived a mid-air with another glider
while flying in those "empty" skies.

Try to picture this. The little device goes "Beep" and when you look at it,
the 20mm 2-digit LED display says "06" meaning 6 gliders are within one
kilometer. My reaction is to look outside like crazy until I can see all
six. It beeps again and displays 07 meaning that another glider has joined
the gaggle. I look even harder. This uses the "Mark 1 eyeball" to it's
maximum.

Extremely accurate GPS data has nothing to do with this. If the error is
that the 7th glider is really 1.005 Km away instead of 1.000 why would I
care? If a glider joins the gaggle without this device there is a very good
chance I will see him while looking for the others even though the device
does not detect him.

It is not necessary to compute the trajectories of all gliders in the gaggle
to determine those with a collision probability. Those 500 feet above and
below present no danger whatsoever.

Now picture an advanced version. The device still displays "07" but it now
sounds "deedle, deedle, deedle" and an LED at 8 O'clock illuminates meaning
that there is a non-zero probability collision threat at that relative
bearing. The "Mark 1 eyeballs" leap into action and I look over my left
shoulder to see that the other glider will pass clear. Is this a "false
alarm"? Not really. I really wanted to see him if he was that close. I
appreciated the "heads up". The device need only compute probabilities for
those targets near and closing while near the same altitude.

Perhaps the problem is calling this an "Anti-Collision Device" when it is
really a situational awareness aid.

As for battery life, perhaps you noticed the news that a fully IFR equipped
Kestral 17 flown by Gordon Boettger flew 1562 Kilometers in 11:15 from
Minden, Nevada, USA to Steamboat Springs, Colorado. Most of the flight was
in wave above 20,000 feet. Gordon's Kestral was transponder equipped as
well as carrying a lot of other electronics to operate legally in positive
control airspace. Battery capacity didn't seem to be a problem.

The device I'm talking about would weigh less than 200 gms and run on four
AA batteries for 50+ hours. The amount of time spent looking at it will be
fractions of a second and then only when critical information is displayed.

Bill Daniels