Re: Strobe light on glider

[Dan Malone]

On Monday, January 23, 2017 at 8:58:52 PM UTC-7, Jonathan St. Cloud wrote:
> A while ago several people remarked that Schleicher gliders offer a strobe was an option.
>
> Below is an URL to a youtube video of such strobe. Typically the strobe is coupled with an unit from LxNav that allow the strobe to be on, only flash with Flarm warning, or off.
>
> https://www.youtube.com/watch?v=XMdGXX11Bs4

Thanks Jonathan for posting this. I have tried to find a simple LED strobe that I could attach to the glider that would use self-contained battery power. perhaps one on the bottom of fuselage and another behind the canopy. I have done a bit of searching on the web trying to find something - but haven't seen anything yet. If anyone is aware of such an device - would appreciate the info.

[John Ferguson]

>
>Thanks Jonathan for posting this. I have tried to find a simple LED

>strobe=

> that I could attach to the glider that would use self-contained battery

>po=

>wer. perhaps one on the bottom of fuselage and another behind the canopy.

>I=

> have done a bit of searching on the web trying to find something - but

>hav=

>en't seen anything yet. If anyone is aware of such an device - would

>apprec=
>iate the info.
>

Link here for a strobe that fits to the canopy

http://www.how2soar.de/index.php/led-blitzer-und-rechenknecht

[John Carlyle]

Not to be a Debbie Downer, but in the previous discussion of glider strobes it was pointed out that battery powered strobes don't have the power to be conspicuous against a bright sky.

Even high-powered airliner strobes don't grab your attention during the day. There's a 737 that usually flies over my house at roughly 2,000 AGL. The plane itself is easy to see, but at closest approach his wing tip strobes are barely visible during the bright conditions typical of a soaring day.

-John, Q3

[John Carlyle]

Jonathan, I do understand your concern. I've seen the fin strobe on an ASG-29 several times, once at Mifflin running ridges on an showery, overcast day with him coming towards me. The strobe was visible, but not that helpful IMHO until he was quite close, and by then I'd already seen the plane itself because of Flarm. YMMV, of course, so my best advice is for you is to do the experiment. Set one up along a straight road on a gloomy day and figure out the distance when it becomes obvious.

-John, Q3

On Tuesday, January 24, 2017 at 11:15:27 AM UTC-5, Jonathan St. Cloud wrote:
> Hi Debbie: I do not know if any studies have been done as to the visibility, but a strobe that is 12 long does put out more of a visual signature than a single point of light, as on most powered aircrat. Imagine, not a bright sky but running under a (dark developed )cloud street at 110 knot IAS at 17,000 ft with another glider flying in opposite direction, same speed. The Flarm goes off and so does the strobe, will that 12 inches of strobe give off enough to catch the eye of the other pilot? That strobe sure is bright, and I have had people tell me that it really stands out. It seems as if the 12 inches of strobe is much more visible than a single point of light.

[Paul Agnew]

I remember watching a documentary on WWII camouflage techniques and am reminded of one counter-intuitive technique that actually used bright lights in daylight to make equipment on the horizon visually disappear. I often ponder the true effectiveness of running with lights on in small powered planes during the day and whether there have been any studies to support the validity of this practice.

Now, you've got me wondering about the effectiveness of bright strobe strips during daylight flights.

Hmmm...

Paul A.
Treasure Coast Soaring Club
Vero Beach, FL

[Paul Agnew]

My Google Fu is strong today. I found a Wiki page about the use of counter-illumination for camouflage that was quite interesting to read.

en.m.wikipedia.org/wiki/Yehudi_lights

From what I'm reading, the brightness of the strobes could work against you as counter-illumination if they are not significantly brighter than the surrounding sky. On a bright, blue sky day, would a bright strobe strip help or hurt your visibility. As I said in my previous post...counter-intuitive...

Paul A.
Treasure Coast Soaring Club
Vero Beach, FL

@TCSoaring on Facebook

[Papa3]

Don't have the energy (ha) today to do a detailed read, but something like this should give some clue:

http://www.imedpub.com/articles/aviation-signal-lighting-impacts-of-lighting-characteristics-on-visibility.pdf

One sentence early on reads: "It is stated that an intensity of 350 cd is required for a signal light to be
visible from 0.125 miles away in conditions corresponding to a runway visual range of 0.125
miles".

So, 1/8 of a mile requires 350 Candela (in a runway setting, where there might be more contrast with ground items?) We probably want 1 mile ideally? So, some math converting Candela to Lumens (which is what is reported in the specs for strobes) would get you some rough approximation of the lumens required to be visible over some reasonable angle (steridians). A very quick back of the envelope tells me that a bike strobe (typically 200-400 lumens) is several orders of magnitude too weak to be useful. Maybe someone has the time to run numbers and make sure I didn't add when I should've divided etc.

P3

[Andrzej Kobus]

There was another study that I posted a link to a couple of months ago. That study concluded that a reflective foil (mirror like) is hugely more effective than LED lights in bright light.

On another note, when ordering my new glider a year ago I asked German pilots about how good the LED lights on the gliders were. The response was not to bother with it.

Saying that LED strobe would sure help under a cloud street. In that situation even a bicycle strobe would help.

[son_of_flubber]

On Wednesday, January 25, 2017 at 12:00:01 PM UTC+13, Andrzej Kobus wrote:

> Saying that LED strobe would sure help under a cloud street. In that situation even a bicycle strobe would help.

I'd be happy just to increase my chances in low light and high on collision risk situations like flying under cloud streets.

To say that, a conspicuity light MUST be effective in bright sunlight in order to be worthwhile, is missing the point.

[Ian]

On 25/01/2017 01:00, Andrzej Kobus wrote:

> There was another study that I posted a link to a couple of months
> ago. That study concluded that a reflective foil (mirror like) is
> hugely more effective than LED lights in bright light.

The UK Military gliding group did a study into high visibility markings
years ago. They did a bunch of flight tests with motor gliders. I think
they found that most markings were not very effective, but reflective
mirror strips on the control surfaces were the most useful. As the
controls move about there is more chance of a reflection flash catching
the other pilots attention.

It was written up in Sailplane and Gliding. It would probably be worth
finding that article before you spend money on anything.

[Jim White]

Problem is that adding foil to the control surfaces would probably alter
the weight and balance beyond limits

[Dan Marotta]

I know the reflective foil/tape is very light, but consider the possible
impact (a pun, perhaps?) of causing an imbalance on a control surface.

--
Dan, 5J

[antar...@gmail.com]

I still think that they did not ask the right question. They asked: What is the average distance at which skilled pilots detect the other traffic, and the distance varied a little bit with the methods, but was always well above the distance necessary to avoid the other traffic. They should have asked the question: How high is the likelihood that the other traffic is detected at a distance of 2 NM. And how you value the different methods might be very different when you use the second question and not the first.

[JS]

What about this option from DG, or whatever they're called this week?
"Flashlight"
Probably looks like Wudolph the Wed Nosed Weindeer!
Jim

http://www.dg-flugzeugbau.de/en/dg-aircraft-news/blitzlich-fuer-dg-1000-und-dg-500-zugelassen/14345?utm_source=wysija&utm_medium=email&utm_campaign=DG+Newsletter+1+2017+e

[son_of_flubber]

On Thursday, January 26, 2017 at 4:09:37 PM UTC+13, JS wrote:

> http://www.dg-flugzeugbau.de/en/dg-aircraft-news/blitzlich-fuer-dg-1000-und-dg-500-zugelassen/14345?utm_source=wysija&utm_medium=email&utm_campaign=DG+Newsletter+1+2017+e

It's curious that this light is red and not white. Is there a regulation that requires forward facing conspicuity lights to be red?

I've seen several forward facing white 'landing lights' on power planes that add conspicuousness.

[Dan Malone]

On Monday, January 23, 2017 at 8:58:52 PM UTC-7, Jonathan St. Cloud wrote:
> A while ago several people remarked that Schleicher gliders offer a strobe was an option.
>
> Below is an URL to a youtube video of such strobe. Typically the strobe is coupled with an unit from LxNav that allow the strobe to be on, only flash with Flarm warning, or off.
>
> https://www.youtube.com/watch?v=XMdGXX11Bs4

Appreciate all the discussion - thanks to all who have contributed.

[Peter Whitehead]

If you want to have strobe lights when you wish to fire them up (situation or Flarm warnings) then it might be worth considering a relatively low tech option with a controller and some "bullet" LED's. I have purchased a kit (controller and three bullet LED's) but have not yet fitted them, so no "review" yet. Have a look at the link..
crazedpilot.com/led-lighting/
Pete

[son_of_flubber]

A case study of what is possible... Guy Westgate's Glider LED installation
https://www.youtube.com/watch?v=7XXfLcN9r3U

[moshe....@gmail.com]

Almost on topic: a quote from John Good's report from WGC2017:

"One notable quirk is a requirement for flashing yellow lights on all vehicles that drive onto the airfield. This curious rule comes not from the contest organization, the gliding club, or the Australia aviation authorities, but rather from the local town government. In the (dangerously) bright Victoria sunlight, a flashing yellow light improves vehicle visibility by a distance measured in centimeters (in some cases you have to look closely to determine that the light is indeed on)."

[mpetr...@gmail.com]

My guess is that strobe helps to see a glider under the cloud base. Also helps during sunset.

[john firth]

In 2017 I designed and installed an LED white strobe driven by
a 10 amp power mosfet,sourced from a 12v 1 ah battery plus super
caps, 2x 5v to give an 18v low impedance power source.
A back to back pair of Chinese 10W white LED s on top of the hor. stab.
The 200msec pulse of 4A 1pps, flash is visible in gloomy
conditions at 400 m. The power stack is recharged by a 12v to 18v
up converter supplied from the glider main bat.
No idea if anyone was alerted.

John F
I have no