Avoid head-on collision? Forward facing LED strobe?

On Wednesday, July 25, 2012 11:07:04 PM UTC-4, Bill D wrote:
(if threat detected) aim a bright and narrow LED beam directly at the other pilot

Keep it simple and cheap. If FLARM detects a threat, turn ON the bright power hungry strobe. Otherwise, turn off the high power strobe (to conserve battery power and minimize distraction.)

In article Eric Greenwell writes:
On 7/25/2012 1:14 AM, Kimmo Hytoenen wrote:
FLARM tells you that there is another glider. It does not really
tell you where it is - you need to look and find it. Week ago I got
FLARM warning, without seeing the another plane.

LED strobe is not a bad idea. Compared to FLARM the cost is
very small, and installation easy. If you have LED strobe, all
other planes will see you, not only those with FLARM.

Are you still talking about a single, forward facing strobe, like the
original poster? If so, a glider coming up below or behind you will not
see the strobe.

If the strobes are placed so they can be seen from all sides, it might
be more useful; however, gaggling might be very distracting! I think
someone has to try this to determine how well it works.

From what I have seen advertized, LED 'strobe' systems have fairly low
power consumption. Putting a set on with 360 degree visibility would seem
to be a good idea.

There are lots of situations where a glider is pretty close to invisible.
Flashing strobes could help in a lot of them.

Alan

After a comprehensive study by the RAF it was found that the colour which

was most conspicuous in a wide variety of daylight conditions was black.

The colour which was least conspicuous was, you guessed it, white or light

grey. Strobe lights are not very effective in bright daylight conditions

and when do we do most of our flying? When the sun shines.

There are very good technical reasons why the top surface of a glider must

be white but does the underside have to be?


I recall a similar study by the FAA (which I can't locate at the moment) in which they found white was the color easiest to see against blue sky. White reflects the most light back to the observer.

I would lean towards a white flashing strobe myself. This should be very easy to see.

On Thursday, August 2, 2012 9:59:51 AM UTC-7, tstock wrote:
After a comprehensive study by the RAF it was found that the colour which



was most conspicuous in a wide variety of daylight conditions was black..



The colour which was least conspicuous was, you guessed it, white or light



grey. Strobe lights are not very effective in bright daylight conditions



and when do we do most of our flying? When the sun shines.



There are very good technical reasons why the top surface of a glider must



be white but does the underside have to be?





I recall a similar study by the FAA (which I can't locate at the moment) in which they found white was the color easiest to see against blue sky. White reflects the most light back to the observer.



I would lean towards a white flashing strobe myself. This should be very easy to see.

There are already gliders out there fitted with strobe lights in the vertical fin and wing tips, so it shouldn't be too difficult to do some tests to confirm if it is effective in daylight or not. From what I heard so far, it is not very effective, but I would like to see the results of a more comprehensive study.

Ramy

I had two near misses flying at a place where the Big Sky theory should be working at its best, Ely, NV. One was the closest I have had outside of a contest. Anyone interested can download the IGC files at:

http://www.onlinecontest.org/olc-2.0...l?dsId=2567554
http://www.onlinecontest.org/olc-2.0...l?dsId=2567342

We were both flying near cloud base at the same altitude in opposite directions. The closing rate was 235 kt. The other pilot saw me about 3 sec (22:52:38), or about 1200 ft, before collision and turned to avoid me (I was checking my position on my map and looked up as he was passing me).

This got me to looking into high intensity LED markers. We all are aware of those used by emergency vehicles; they can be seen in bright sunlight at a long distance. I was thinking of mounting one inside the cockpit of my DG400 in front of the instrument pod. I would have to modify the flash circuitry reduce the rate (thereby reducing power consumption). One potential source is:

http://www.extremetacticaldynamics.com/

The cost is a small fraction of a FLARM, and will work with non-FLARM equipped aircraft.

Tom

On Wednesday, August 15, 2012 2:35:18 PM UTC-4, 2G wrote:

We were both flying near cloud base at the same altitude in opposite directions.

This is the scenario that prompted my original post.

On Wednesday, August 15, 2012 2:46:13 PM UTC-4, son_of_flubber wrote:
On Wednesday, August 15, 2012 2:35:18 PM UTC-4, 2G wrote:

We were both flying near cloud base at the same altitude in opposite directions.

This is the scenario that prompted my original post.

I would add that if you're underneath a cloud then you are by definition NOT in direct sunlight and your background in many cases will be a dark cloud. Please post a followup if you install a light.

There's a glider competing here in Uvalde with an array of about 12 LED double-strobing blubs on the leading edge of his vertical fin. A plastic lens conforming to the leading edge's airfoil shape covered the bulbs. We saw it working the other day during a landing period in which a gust front delayed landing late. The sky's light was low (about 10 minutes before sunset) and we saw him easily before we could make out the glider. It works great! It would be very useful when thermalling under a CU in the shadows. I give it thumbs up for head-on collision avoidance.

It would be cool if you could interface it to the PowerFlarm and have it activate only when PF detected an aircraft within a mile of you. I thought this design was really nice.

On Wednesday, August 15, 2012 4:52:11 PM UTC-4, BobD wrote:

It would be cool if you could interface it to the PowerFlarm and have it activate only when PF detected an aircraft within a mile of you.

Or you could keep the blink rate low until you visually see another glider, then boost the frequency and intensity. If both gliders had this feature, it would confirm when the other glider has you in sight.

One recurrent problem with a glider approaching head on is that you cannot read the tail number to give him a heads up on the radio. I guess you could always say "Glider approaching head-on" to get his attention. What would be a good "heads-up" radio call in this situation?

On Wednesday, August 15, 2012 11:35:18 AM UTC-7, 2G wrote:
I had two near misses flying at a place where the Big Sky theory should be working at its best, Ely, NV. One was the closest I have had outside of a contest. Anyone interested can download the IGC files at:



http://www.onlinecontest.org/olc-2.0...l?dsId=2567554

http://www.onlinecontest.org/olc-2.0...l?dsId=2567342



We were both flying near cloud base at the same altitude in opposite directions. The closing rate was 235 kt. The other pilot saw me about 3 sec (22:52:38), or about 1200 ft, before collision and turned to avoid me (I was checking my position on my map and looked up as he was passing me).



This got me to looking into high intensity LED markers. We all are aware of those used by emergency vehicles; they can be seen in bright sunlight at a long distance. I was thinking of mounting one inside the cockpit of my DG400 in front of the instrument pod. I would have to modify the flash circuitry reduce the rate (thereby reducing power consumption). One potential source is:



http://www.extremetacticaldynamics.com/



The cost is a small fraction of a FLARM, and will work with non-FLARM equipped aircraft.



Tom

The big sky theory does not apply to gliders, this is why we keep having midairs and near misses. Most of us had similar experience at least once. Reason is that gliders congregate in relatively small portion of the sky, especially when cloudstreets are presented, we are all following the same energy lines at the same altitudes, and worth, our eyes are often focused above the horizon to follow the best line.

Please continue your research and post the results. Sometime all it takes is for someone to find an easy solution which works and the rest of us will follow. I am flying for years with reflective tapes on my wingtips but still can't say for sure if it is effective or not, but it doesn't hurt...

Ramy