Strobes

[Jim Kellett]

Some years back there was an article (maybe several?) in SOARING magazine
about installing tip strobes on gliders ...

Anyone remember/know what issue(s) that was in? I'm researching collision
avoidance stuff (again, still . . <gr>)

(Boy, do I wish there was a good INDEX to Soaring! I've got every copy
since 1966 and a few going back to 1937, making a fantastic resource that's
darn near unusuable because there are no complete indices (and the few that
were printed back in the seventies and eighties are poorly organized . . .))

Jim Kellett

[Mark Zivley]

Dick Johnson wrote one some time back, but I don't remember which issue.
Sorry. However, I believe he concluded that the distance at which the
strobe was noticeable during the day was so relatively short that there
was minimal benefit to the installation.

Jim Kellett wrote:
> Some years back there was an article (maybe several?) in SOARING magazine
> about installing tip strobes on gliders ...
>
> Anyone remember/know what issue(s) that was in? I'm researching collision
> avoidance stuff (again, still . . <gr>)
>
> (Boy, do I wish there was a good INDEX to Soaring! I've got every copy
> since 1966 and a few going back to 1937, making a fantastic resource that's
> darn near unusuable because there are no complete indices (and the few that
> were printed back in the seventies and eighties are poorly organized . . .))
>
> Jim Kellett
>
>

[bumper]

The other issue is power consumption. The Whelan Cometflash strobes in my
Mooney draw about 7 amps at 12 volts. They're bright, perhaps even bright
enough to be effective in daylight. On the other hand, the stobes in my
Stemme draw only about 2 amps . . . nowhere near as bright, they would be
next to useless in daylight.
--
bumper ZZ (reverse all after @)>
"Dare to be different . . . circle in sink."

"Mark Zivley" > wrote in message
...
> Dick Johnson wrote one some time back, but I don't remember which issue.
> Sorry. However, I believe he concluded that the distance at which the
> strobe was noticeable during the day was so relatively short that there
> was minimal benefit to the installation.
>
> Jim Kellett wrote:
> > Some years back there was an article (maybe several?) in SOARING
magazine
> > about installing tip strobes on gliders ...
> >
> > Anyone remember/know what issue(s) that was in? I'm researching
collision
> > avoidance stuff (again, still . . <gr>)
> >
> > (Boy, do I wish there was a good INDEX to Soaring! I've got every copy
> > since 1966 and a few going back to 1937, making a fantastic resource
that's
> > darn near unusuable because there are no complete indices (and the few
that
> > were printed back in the seventies and eighties are poorly organized . .
..))
> >
> > Jim Kellett
> >
> >
>

[Stefan]

Jim Kellett wrote:

> Some years back there was an article (maybe several?) in SOARING magazine
> about installing tip strobes on gliders ...

We tried it at our field last year. The result was that we consistently
saw the glider long before the strobes... The problem is that you don't
have enough energy to power strobes that would really be seen.

Stefan

[Steve Hopkins]

Ordinary strobes are, as has been agreed, not powerful enough to make
much of a contribution to visibility. However, a former glider pilot and
electronic engineer, Phil Manning, is developing an LED flash to perform
the same function. The "flashes" are of much higher intensity but of
much shorter duration than that emitted from a strobe so current
drainage is reasonable. Furthermore, as this is a cold light, the
casings can be moulded to conform with the glider thereby reducing any
extra drag. I suggest that anyone interested in his work contact him
directly at;-
Steve


-----Original Message-----
From: Glider Pilot Network ]
Sent: Monday, December 01, 2003 2:40 AM
To: Steve Hopkins
Subject: [r.a.s] Re: Strobes


------------------------------------------------------------
Newsgroup: rec.aviation.soaring
Subject: Re: Strobes
Author: Mark Zivley >
Date/Time: 02:30 01 December 2003
------------------------------------------------------------
Dick Johnson wrote one some time back, but I don't remember which issue.

Sorry. However, I believe he concluded that the distance at which the

strobe was noticeable during the day was so relatively short that there

was minimal benefit to the installation.

Jim Kellett wrote:
> Some years back there was an article (maybe several?) in SOARING
> magazine about installing tip strobes on gliders ...
>
> Anyone remember/know what issue(s) that was in? I'm researching
> collision avoidance stuff (again, still . . )
>
> (Boy, do I wish there was a good INDEX to Soaring! I've got every
> copy since 1966 and a few going back to 1937, making a fantastic
> resource
that's
> darn near unusuable because there are no complete indices (and the few
that
> were printed back in the seventies and eighties are poorly organized
. .))
>
> Jim Kellett
>
>


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

[Eric Greenwell]

Steve Hopkins wrote:

> Ordinary strobes are, as has been agreed, not powerful enough to make
> much of a contribution to visibility. However, a former glider pilot and
> electronic engineer, Phil Manning, is developing an LED flash to perform
> the same function. The "flashes" are of much higher intensity but of
> much shorter duration than that emitted from a strobe so current
> drainage is reasonable. Furthermore, as this is a cold light, the
> casings can be moulded to conform with the glider thereby reducing any
> extra drag. I suggest that anyone interested in his work contact him
> directly at;-

Current strobes already have such a short duration I believe it is not a
factor; instead, the eye is just responding to the "total energy"
emitted by the flash. If I'm right, then a brighter, shorter duration
flash won't help any, and unless the LED's are more efficient at
converting energy to light (or have a more visible spectrum) than the
flash tubes used, there won't be any reduction in power required.

There may be other advantages, such cheaper, smaller, and lighter
circuitry because high voltages aren't required, and a more rugged unit.
A good test before planning to install them would be to try them near to
a conventional strobe in daylight, and start walking away until you lose
sight of one them! Let us know when some testing has been done.

Reducing the repetition rate is a simple way to cut current consumption,
and would be acceptable for typical glider speeds, unless regulation
prohibit it.

--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

[Vaughn]

"Eric Greenwell" > wrote in message
...
> Steve Hopkins wrote:
> There may be other advantages, such cheaper, smaller, and lighter
> circuitry because high voltages aren't required, and a more rugged unit.

For what it is worth; police light bars, for which the best technology
has previously been stobes, are now available using LEDs instead. I haven't
seen them yet, but you have all probably seen LED traffic signals, they do a
great job, even in the brightest Florida sunlight, on a fraction of the
energy of incandescent lights. I hadn't thought of it until just now, but
LEDs may someday have real promise enhancing glider visibility.

Vaughn

[Jim Kelly]

Has anyone thought to try (very) reflective tape, perhaps covering
the nose area and leading edges of the vertical fin?

We would need to use a malleable material to adapt to the curvaceous
shapes but the sun glinting off these curved surfaces might just
work, thus saving on the energy required to use strobes, LEDs and
the like!

Cheers,

Jim Kelly.



"Jim Kellett" > wrote in message
. ..
| Some years back there was an article (maybe several?) in SOARING
magazine
| about installing tip strobes on gliders ...
|
| Anyone remember/know what issue(s) that was in? I'm researching
collision
| avoidance stuff (again, still . . <gr>)
|
| (Boy, do I wish there was a good INDEX to Soaring! I've got every
copy
| since 1966 and a few going back to 1937, making a fantastic
resource that's
| darn near unusuable because there are no complete indices (and the
few that
| were printed back in the seventies and eighties are poorly
organized . . .))
|
| Jim Kellett
|
|

[tango4]

Hi

Solarfilm, the heat activated model aircraft covering does a chrome finish
film. A couple of sections of this would probably be more effective than
'orange dayglo' that we currently use. The BGA did some empirical testing
and remarked that reflective film ( 3M mirror ) seemed the best solution.
( S&G Aug/Sep 2003 )

Perhaps we should all be flying polished HP18's!

Ian

"Jim Kelly" > wrote in message
u...
> Has anyone thought to try (very) reflective tape, perhaps covering
> the nose area and leading edges of the vertical fin?
>
> We would need to use a malleable material to adapt to the curvaceous
> shapes but the sun glinting off these curved surfaces might just
> work, thus saving on the energy required to use strobes, LEDs and
> the like!
>
> Cheers,
>
> Jim Kelly.
>
>
>
> "Jim Kellett" > wrote in message
> . ..
> | Some years back there was an article (maybe several?) in SOARING
> magazine
> | about installing tip strobes on gliders ...
> |
> | Anyone remember/know what issue(s) that was in? I'm researching
> collision
> | avoidance stuff (again, still . . <gr>)
> |
> | (Boy, do I wish there was a good INDEX to Soaring! I've got every
> copy
> | since 1966 and a few going back to 1937, making a fantastic
> resource that's
> | darn near unusuable because there are no complete indices (and the
> few that
> | were printed back in the seventies and eighties are poorly
> organized . . .))
> |
> | Jim Kellett
> |
> |
>

[F.L. Whiteley]

"Vaughn" > wrote in message
...
>
> "Eric Greenwell" > wrote in message
> ...
> > Steve Hopkins wrote:
> > There may be other advantages, such cheaper, smaller, and lighter
> > circuitry because high voltages aren't required, and a more rugged unit.
>
> For what it is worth; police light bars, for which the best
technology
> has previously been stobes, are now available using LEDs instead. I
haven't
> seen them yet, but you have all probably seen LED traffic signals, they do
a
> great job, even in the brightest Florida sunlight, on a fraction of the
> energy of incandescent lights. I hadn't thought of it until just now, but
> LEDs may someday have real promise enhancing glider visibility.
>
> Vaughn
>
And reducing your domestic energy requirements.

Frank

[Stefan]

Jim Kelly wrote:

> Has anyone thought to try (very) reflective tape,

Of course. Our club has equipped all gliders with chrome tape. The
opinions vary from "it doesn't hurt" to "we will be able to claim that
we tried everything".

Stefan

[Mark James Boyd]

>Jim Kelly wrote:
>
>> Has anyone thought to try (very) reflective tape,

Yes. Reflective tape, and if you repaint a glider,
paint the wingtips white or reflective. It seems I've
seen quite a few with dark wingtips. Sure makes
it easy to hit one's head...

I also wrap my portable ELT in reflective tape. Saves
having a separate mirror...

[Mark James Boyd]

In article >,
Eric Greenwell > wrote:
>Mark James Boyd wrote:
>>>Jim Kelly wrote:
>
>> I also wrap my portable ELT in reflective tape. Saves
>> having a separate mirror...
>
>Have you tried to use it? A real signalling mirror is flat, reflective
>on both sides, and has a small hole in the center so you can aim it. One
>you can't aim might be worthless.
>--

This tape actually has a checker pattern and
reflects in all directions. I'd bet the signal mirror
would work better, but might depend on my skill
using it ;-[

[Eric Greenwell]

Mark James Boyd wrote:
>>Jim Kelly wrote:

> I also wrap my portable ELT in reflective tape. Saves
> having a separate mirror...

Have you tried to use it? A real signalling mirror is flat, reflective
on both sides, and has a small hole in the center so you can aim it. One
you can't aim might be worthless.
--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

[Eric Greenwell]

Mark James Boyd wrote:
> In article >,
> Eric Greenwell > wrote:
>
>>Mark James Boyd wrote:
>>
>>>>Jim Kelly wrote:
>>
>>>I also wrap my portable ELT in reflective tape. Saves
>>>having a separate mirror...
>>
>>Have you tried to use it? A real signalling mirror is flat, reflective
>>on both sides, and has a small hole in the center so you can aim it. One
>>you can't aim might be worthless.
>>--
>
>
> This tape actually has a checker pattern and
> reflects in all directions.

I think this makes it worthless unless the other person is very close. A
flat signal mirror has a narrow and therefor much brighter beam.

> I'd bet the signal mirror
> would work better, but might depend on my skill
> using it ;-[

They are very easy to aim, because they are reflective on _both_ sides
and have a hole in the center. You are actually aiming it (using the
hole and the reflective back side), not just waving it in the general
direction of the aircraft or whatever you are trying to signal.


--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

[Robert John]

SNIP
A
>flat signal mirror has a narrow and therefor much brighter
>beam.
>
>> I'd bet the signal mirror
>> would work better, but might depend on my skill
>> using it ;-[
>
>They are very easy to aim, because they are reflective
>on _both_ sides
>and have a hole in the center. You are actually aiming
>it (using the
>hole and the reflective back side), not just waving
>it in the general
>direction of the aircraft or whatever you are trying
>to signal.
>
>
>--
>-----
>Replace 'SPAM' with 'charter' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
>Eric,
Not ever having seen one, I can't quite get my mind
around how a hole in the centre helps you aim it.
If the sun is 45 degrees left and you aim at the target
aircraft, won't the reflected beam be 45 degrees right
of the target?
I'm not arguing - I'm sure they work, I'd just like
a simple explanation of how!
Rob

[Bob Gibbons]

On 5 Dec 2003 16:38:12 GMT, Robert John
> wrote:
.... text removed...
>Not ever having seen one, I can't quite get my mind
>around how a hole in the centre helps you aim it.
> If the sun is 45 degrees left and you aim at the target
>aircraft, won't the reflected beam be 45 degrees right
>of the target?
>I'm not arguing - I'm sure they work, I'd just like
>a simple explanation of how!

This may not be simple, but most of the real signal mirrors I am
familar with have a hole in the backside that is surrounded with a
circle of retroreflective material (like 3M Scotchlite), typically red
in color. The sunlight is reflected off the mirror surface normally.
Where the sunlight hits the Scotchlite, it is retroreflected directly
only the incoming path. A small portion (about 4%) of this reflected
sunlight, now colored red by the Scotchlite, is in turn reflected
backwards again by the front surface of the mirror (toward the user
looking through the backside of the mirror). The usual optics rules
for mirrors (angle of incidence equals angle of reflection) means that
this retroreflected (red) radiation appears to come along the exact
angle as the outgoing reflected sun light. The bottom line is that
when you look outward through the small hole in the backside of the
mirror, all you have to do is put the small red spot you see on the
target you are trying to signal. The Scotchlite properties and the
rules of optics reflection assure that the red spot and the reflected
sunlight are pointing in the exact same direction.

Sorry UseNet does not permit embedded graphics.

Bob

[Slingsby]

Robert John > wrote in message >...
> SNIP
> A
> >flat signal mirror has a narrow and therefor much brighter
> >beam.
> >
> >> I'd bet the signal mirror
> >> would work better, but might depend on my skill
> >> using it ;-[
> >
> >They are very easy to aim, because they are reflective
> >on _both_ sides
> >and have a hole in the center. You are actually aiming
> >it (using the
> >hole and the reflective back side), not just waving
> >it in the general
> >direction of the aircraft or whatever you are trying
> >to signal.
> >
> >
> >--
> >-----
> >Replace 'SPAM' with 'charter' to email me directly
> >
> >Eric Greenwell
> >Washington State
> >USA
> >
> >Eric,
> Not ever having seen one, I can't quite get my mind
> around how a hole in the centre helps you aim it.
> If the sun is 45 degrees left and you aim at the target
> aircraft, won't the reflected beam be 45 degrees right
> of the target?
> I'm not arguing - I'm sure they work, I'd just like
> a simple explanation of how!
> Rob

You can also buy little stick on convex mirrors for $2.00 or less each
at auto parts stores. Wouldn't the reflected light go out in a cone
shape? After a few hundred feet the cone pattern could be quite
large.

[Vaughn]

"Slingsby" > wrote in message
om...
> Robert John > wrote in
message >...
> > SNIP
> > A
> > >flat signal mirror has a narrow and therefor much brighter
> > >beam.

>
> You can also buy little stick on convex mirrors for $2.00 or less each
> at auto parts stores. Wouldn't the reflected light go out in a cone
> shape? After a few hundred feet the cone pattern could be quite
> large.

...and therefore (by the law of inverse squares) not nearly as bright.

Vaughn