PowerFLARM leeching comments

On Wednesday, October 31, 2012 10:00:03 PM UTC+1, Don Johnstone wrote:
Better lookout and situational awareness is they key, anyone who thinks

otherwise should stay at home in a locked room, they are far too dangerous

to be allowed out.

You know whats far more dangerous? Pilots resistant to critique.

If three pilots tell you that what you are doing|thinking is wrong or dangerous: it probably is.

Don, can you back up your claim that Flarm was designed mainly for wave flying by providing some reference?
Also,can you share with us your actual experience flying with Flarm?

Ramy

At 02:05 01 November 2012, Ramy wrote:
Don, can you back up your claim that Flarm was designed mainly for wave
flying by providing some reference?
Also,can you share with us your actual experience flying with Flarm?

Ramy

The original FLARM was conceived to assist pilots in detecting difficult to
see gliders, particulary in wave where the relative movement is small, the
closure rate is slow and the track of another glider cannot easily be
detected by observing the way it is pointing.
I fly a Discus fitted with FLARM and an LX8000. The LX8000 linked to the
FLARM provides a "radar" display on the moving map. I have found the system
to be useful when flying in wave, I have found it to be less useful, if not
distracting in thermals. On a short 3 mile ridge with 20 or 30 gliders it
is positively lethal.
I do not use the LX8000 display at all when flying a ridge or in thermals.
I have used it when flying in wave, however I still feel the time spent
looking at the LX display and trying to make sense of it would be better
spent looking out.
The most scary thing, even using just the clock lights on the basic system,
is that it is misleading when flying a ridge in higher wind speeds. The
light bears no relation to the direction of the threat so I hear the bleep
and look all round. I have to say that there have been very few occasions
when the alert has sounded and I have not seen the glider causing it before
the alert sounded, lucky maybe?

On Wednesday, October 31, 2012 10:05:38 PM UTC-4, Ramy wrote:
Don, can you back up your claim that Flarm was designed mainly for wave flying by providing some reference? Also,can you share with us your actual experience flying with Flarm? Ramy

I recall hearing that Flarm was developed to attempt to address the issue of mid air collisions and collisions with obstacles in the Alps. There is a big issue with coming around the corner of a rock and there is another glider. They also have a huge number of wires and such that you can't see.
Maybe the Flarm folks can clarify this bit of history. I'm sure we all would like to know.
UH

On Thursday, November 1, 2012 5:45:02 AM UTC-7, Don Johnstone wrote:
At 02:05 01 November 2012, Ramy wrote:

Don, can you back up your claim that Flarm was designed mainly for wave

flying by providing some reference?

Also,can you share with us your actual experience flying with Flarm?



Ramy



The original FLARM was conceived to assist pilots in detecting difficult to

see gliders, particulary in wave where the relative movement is small, the

closure rate is slow and the track of another glider cannot easily be

detected by observing the way it is pointing.

I fly a Discus fitted with FLARM and an LX8000. The LX8000 linked to the

FLARM provides a "radar" display on the moving map. I have found the system

to be useful when flying in wave, I have found it to be less useful, if not

distracting in thermals. On a short 3 mile ridge with 20 or 30 gliders it

is positively lethal.

I do not use the LX8000 display at all when flying a ridge or in thermals..

I have used it when flying in wave, however I still feel the time spent

looking at the LX display and trying to make sense of it would be better

spent looking out.

The most scary thing, even using just the clock lights on the basic system,

is that it is misleading when flying a ridge in higher wind speeds. The

light bears no relation to the direction of the threat so I hear the bleep

and look all round. I have to say that there have been very few occasions

when the alert has sounded and I have not seen the glider causing it before

the alert sounded, lucky maybe?

Lucky, yes.

In a dozen flights I probably picked up 10-15 conflicts that I had not already determined to be a threat visually. Examples include: an LS-8 doing a zoomie from down below my nose after overtaking me from behind/below, a Discus 2 that decided to leave a thermal by cutting through the middle of the circle and across my path from above/behind, a glider a half mile abeam of me that changed to a converging course line. On top of that there were multiple cases of traffic encountered on course and gliders adjusting their circles in thermals, I found most of them immediately useful and a couple were downright sobering.

I never use the radar display in a thermal - it's not good for that and not intended for that, but it is useful in making you aware when a glider you might not have seen is now in your general vicinity. Mis-using the radar display by going heads-down in close quarters is not grounds for a sweeping criticism of the device. You could make the same criticism of an airspeed indicator - staring at it until you fly into an obstacle would be dangerous and dumb, but isn't a reason to remove the instrument from your panel.

I recall the same as UH - that Flarm was developed for Alpine flying, but not especially for wave - (which is a small portion of overall flight time). I always understood Flarm was targeted at a general set of glider collision threat scenarios - all of which would be exacerbated by the traffic funneling that mountain flying of every form tends to generate. I expect Urs could clarify.

9B

I have had most conflicts when flying under cloud streets, including one incident a couple of years ago where I nearly collided head-on with a colleague at very high closing speeds. My concern with PowerFlarm and its cheesy antennas is that the range may not be sufficient to adequately warn me in this scenario. The more information the unit can provide the better - that is why I oppose use of the"stealth" mode.

Mike

On Nov 1, 9:23*am, Mike the Strike wrote:
I have had most conflicts when flying under cloud streets, including one incident a couple of years ago where I nearly collided head-on with a colleague at very high closing speeds. *My concern with PowerFlarm and its cheesy antennas *is that the range may not be sufficient to adequately warn me in this scenario. *The more information the unit can provide the better - that is why I oppose use of *the"stealth" mode.

Mike

Mike,

I had exactly that scenario at Parowan during the nationals this
year. Was near cloudbase at about 17,000 feet and doing over 100
knots indicated or about 120 mph over the ground. Light angle was low
as I was running back to the southwest and the air noise from flying
fast made it hard to hear the Flarm. My Butterfly display switched to
conflict mode and showed a target straight ahead and at my altitude.
I banked immediately and dove in time to watch W3 pass me in the
opposite direction at about the same speed. Closing speed was around
240 mph (390 kmh), this would have worked in stealth mode so I have
no problems recommending stealth mode for contests.

Tim (TT)

At 15:23 01 November 2012, Mike the Strike wrote:
I have had most conflicts when flying under cloud streets,
including one
in=
cident a couple of years ago where I nearly collided head-
on with a
colleag=
ue at very high closing speeds. My concern with
PowerFlarm and its cheesy
=
antennas is that the range may not be sufficient to
adequately warn me in
=
this scenario. The more information the unit can provide
the better -
that=
is why I oppose use of the"stealth" mode.

Mike


Mike,

This link to an illustration of glider sizes versus time to
impact and speeds might offer reassurance about
sufficiency of warning in the head on case - assuming that
the PF range collision alert range is at least as good as the
less powerful Swiss Flarm version.

For example, with both gliders doing 108 knots towards
each other on a collision course, the first PF alert would be
at around 2km separation and at that distance a 15m
wingspan will subtend an angle smaller than a screw head
on the instrument panel.

http://www.flarm.com/files/glider_shapes_en.pdf

John Galloway

On Thu, 01 Nov 2012 05:50:48 -0700, unclhank wrote:

I recall hearing that Flarm was developed to attempt to address the
issue of mid air collisions and collisions with obstacles in the Alps.
There is a big issue with coming around the corner of a rock and there
is another glider. They also have a huge number of wires and such that
you can't see.

I heard that too - especially the point about flying round a corner in a
mountain face and meeting traffic coming the other way. I think that also
explains the built-in obstacle database.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Thursday, November 1, 2012 8:48:01 AM UTC-7, Tim Taylor wrote:
On Nov 1, 9:23*am, Mike the Strike wrote: I have had most conflicts when flying under cloud streets, including one incident a couple of years ago where I nearly collided head-on with a colleague at very high closing speeds. *My concern with PowerFlarm and its cheesy antennas *is that the range may not be sufficient to adequately warn me in this scenario. *The more information the unit can provide the better - that is why I oppose use of *the"stealth" mode. Mike Mike, I had exactly that scenario at Parowan during the nationals this year. Was near cloudbase at about 17,000 feet and doing over 100 knots indicated or about 120 mph over the ground. Light angle was low as I was running back to the southwest and the air noise from flying fast made it hard to hear the Flarm. My Butterfly display switched to conflict mode and showed a target straight ahead and at my altitude. I banked immediately and dove in time to watch W3 pass me in the opposite direction at about the same speed. Closing speed was around 240 mph (390 kmh), this would have worked in stealth mode so I have no problems recommending stealth mode for contests. Tim (TT)

Tim,

I would have seen the target apporximately 4 mile out on my Ultimate Le Display, and then the Lady would warn me of the traffic, so I do not recommend the Stealth Mode. More time to identify the threat is much better.

Richard
www.craggyaero.com