Passive Reflective Devices

[henkelize]

Hi everybody

I would like to gather some information about a passive reflective device
which could be used to increase the visibility of a glider. It was
described to me as follows, during one of those typical launch point chats:

It takes the shape of small sphere, mounted just behind the canopy on
the turtle deck
The surface is covered with faceted mirrors, like a disco mirror ball

Apparently this little ball will sparkle as light from the sun is reflected
to the observer, thus making the glider more visible. Now my questions are
as follows:

Has anybody ever seen or heard of such a device?
If yes, how can one obtain these little do-hickeys, i.e. price and point
of sale.
Do they actually work?

Any other suggestions for passive reflective devices will also be
appreciated. Suggestions and thoughts on active devices, i.e. strobes will
also be handy.

Regards

Henk Stander

[henkelize]

It does not have to be very big. I'm thinking about the size of a squash
ball.

Regards

Henk

"Derrick Steed" > wrote in message
...
> Henkelize wrote:
> >It takes the shape of small sphere, mounted just behind the canopy on
> >the turtle deck
> >The surface is covered with faceted mirrors, like a disco mirror ball
> >
>
> Are you prepared to pay for the drag it will cost you?
>
> Rgds,
>
> Derrick Steed
>
>
>
>

[Derrick Steed]

Henkelize wrote:
>It takes the shape of small sphere, mounted just behind the canopy on
>the turtle deck
>The surface is covered with faceted mirrors, like a disco mirror ball
>

Are you prepared to pay for the drag it will cost you?

Rgds,

Derrick Steed

[Derrick Steed]

That's still about as much as the width of the glider fuselage - you'd need to design a fairing for it.

Rgds,

Derrick.
>It does not have to be very big. I'm thinking about the size of a squash
>ball.
>
>Regards
>
>Henk
>
>"Derrick Steed" wrote in message
> ...
>> Henkelize wrote:
>> >It takes the shape of small sphere, mounted just behind the canopy on
>> >the turtle deck
>> >The surface is covered with faceted mirrors, like a disco mirror ball
>> >
>>
>> Are you prepared to pay for the drag it will cost you?
>>
>> Rgds,
>>
>> Derrick Steed
>>
>>
>>


Rgds,

Derrick Steed

[Mike Lindsay]

In article >, henkelize
> writes
>Hi everybody
>
>I would like to gather some information about a passive reflective device
>which could be used to increase the visibility of a glider. It was
>described to me as follows, during one of those typical launch point chats:
>
> It takes the shape of small sphere, mounted just behind the canopy on
>the turtle deck
> The surface is covered with faceted mirrors, like a disco mirror ball
>
>Apparently this little ball will sparkle as light from the sun is reflected
>to the observer, thus making the glider more visible. Now my questions are
>as follows:
>
> Has anybody ever seen or heard of such a device?
> If yes, how can one obtain these little do-hickeys, i.e. price and point
>of sale.
> Do they actually work?
>
>Any other suggestions for passive reflective devices will also be
>appreciated. Suggestions and thoughts on active devices, i.e. strobes will
>also be handy.
>
>Regards
>
>Henk Stander
>
>
>
Many years ago I had the same thought. I made up a reflector from 3
polystyrene ceiling tiles arranged at right angles to each other, and
covered with kitchen foil. (If you arrange mirrors like this a light ray
striking it will be sent back from where it came, it works with radar
too.)

Then I found there wasn't room in the glider for it.

Maritime radar reflectors are available, they are also too big...
--
Mike Lindsay

[Tim Ward]

"henkelize" > wrote in message
...
> Hi everybody
>
> I would like to gather some information about a passive reflective device
> which could be used to increase the visibility of a glider. It was
> described to me as follows, during one of those typical launch point
chats:
>
> It takes the shape of small sphere, mounted just behind the canopy on
> the turtle deck
> The surface is covered with faceted mirrors, like a disco mirror ball
>
> Apparently this little ball will sparkle as light from the sun is
reflected
> to the observer, thus making the glider more visible. Now my questions
are
> as follows:
>
> Has anybody ever seen or heard of such a device?
> If yes, how can one obtain these little do-hickeys, i.e. price and
point
> of sale.
> Do they actually work?
>
> Any other suggestions for passive reflective devices will also be
> appreciated. Suggestions and thoughts on active devices, i.e. strobes
will
> also be handy.
>
> Regards
>
> Henk Stander

A number of years ago, some hang glider pilots in the Owens Valley were
using golf-ball sized or tennis-ball sized "mirrored disco balls" attached
to the kingpost. You'd get a bright flash occasionally, and it tended to
draw the eye. I think it did help some with visibility.
Nowadays, the kingposts are mostly gone, and I imagine so are the disco
balls.
And I'm still not much help, because I don't know where the people that had
them, got them.

Tim Ward

[Lennie the Lurker]

"henkelize" > wrote in message >...
> Hi everybody
>
> I would like to gather some information about a passive reflective device
> which could be used to increase the visibility of a glider. It was
> described to me as follows, during one of those typical launch point chats:
>
> It takes the shape of small sphere, mounted just behind the canopy on
> the turtle deck
> The surface is covered with faceted mirrors, like a disco mirror ball
>
> Apparently this little ball will sparkle as light from the sun is reflected
> to the observer, thus making the glider more visible. Now my questions are
> as follows:
>
> Has anybody ever seen or heard of such a device?
> If yes, how can one obtain these little do-hickeys, i.e. price and point
> of sale.
> Do they actually work?
>
> Any other suggestions for passive reflective devices will also be
> appreciated. Suggestions and thoughts on active devices, i.e. strobes will
> also be handy.
>
> Regards
>
> Henk Stander

http://mathworld.wolfram.com/topics/LiveGraphics3DApplets.html

Pick your shape and have at it.

[John Giddy]

Mike Lindsay wrote:
> Many years ago I had the same thought. I made up a reflector from 3
> polystyrene ceiling tiles arranged at right angles to each other,
and
> covered with kitchen foil. (If you arrange mirrors like this a light
> ray striking it will be sent back from where it came, it works with
> radar too.)
>
> Then I found there wasn't room in the glider for it.
>
> Maritime radar reflectors are available, they are also too big...

Mike,
I think Henk was talking about a reflector for sunlight, not radar
transmissions.
This means he needs to have the reflector on the outside of the glider
so it can be seen by others.
The main problem seems to be the drag issue, and then whether it is
any use anyway.
IMO unless very large, it won't be visible at any useful distance.
Even strobe lights aren't that good in bright sunshine after about
half a kilometer.
Cheers, John G.

[Mike]

> A number of years ago, some hang glider pilots in the Owens Valley were
> using golf-ball sized or tennis-ball sized "mirrored disco balls" attached
> to the kingpost. You'd get a bright flash occasionally, and it tended to
> draw the eye. I think it did help some with visibility.
> Nowadays, the kingposts are mostly gone, and I imagine so are the disco
> balls.
> And I'm still not much help, because I don't know where the people that had
> them, got them.
>
> Tim Ward

I remember those little disco balls (abour the size of a tennis ball)
and I remember that at more than 300 meters or so the flash given off
was no longer discernable, probably because of the very small faceted
surfaces on them.

Mike Z

[J.M. Farrington]

> Any other suggestions for passive reflective devices will also be
> appreciated. Suggestions and thoughts on active devices, i.e. strobes
will
> also be handy.
>
> Regards
>
> Henk Stander

Seeing that you are going to be using Lawrence Welk's mirrored ball, you
should also attach his perpetual bubble machine, and use it for thermal
location.

John

[Steve Hopkins]

For brilliant strobe lights that are incredibly power
efficient contact Phil Manning. He is an engineer and
ex-glider pilot who has developed high intensity, flashig
LED's. They are 'cold' so can be housed in an aerodynamic
shape. His email is :-


For a reflective device, why not simply apply a reflective
caoting to the canopy? A bit like those mirrored glasses.
They are still available for use as automobile accessories.
They also make the cockpit a bit cooler. If anyone
thinks of adopting this approach, however, do also
ensure that your eyes have adequate protection against
UV light. A dark tint to the canopy will cause the
pupils to enlarge thereby exposing the lense of the
eye to more of the ambient UV light with concommitant
risk of cattaract formation.

At 06:36 11 July 2004, J.M. Farrington wrote:
>
>
>> Any other suggestions for passive reflective devices
>>will also be
>> appreciated. Suggestions and thoughts on active devices,
>>i.e. strobes
>will
>> also be handy.
>>
>> Regards
>>
>> Henk Stander
>
>Seeing that you are going to be using Lawrence Welk's
>mirrored ball, you
>should also attach his perpetual bubble machine, and
>use it for thermal
>location.
>
>John
>
>
>

[Gordon Schubert]

WHAT ABOUT REFLECTIVE TAPE?
GORDY

[COLIN LAMB]

Interesting question - to give a "sparkle" to make the glider more visible.

I have a mirror in my search and rescue pack. The survival mirror has great
range. Mirrors have been spotted 50 miles away. However, they need to be
aimed. What you are proposing is to use an assembly that has multiple
reflecting surfaces so that aiming becomes unnecessary.

There are problems, however. As the surface number increases, the
reflections are reduced in magnitude. Fortunately, the original source is
substantial. A good mathematician could determine the probabilities of a
reflection, knowing the number of surfaces, the various possible locations
of the sun and the other aircraft and and the likely possibility of the
other pilot looking into an area that might contain the glint.

Some collisions are from below or above. The reflector would not do much
good in those directions.

If he (or she) has their head "in the cockpit", it will not be much good. I
fly a helicopter that has a strobe on all the time and it does not do much
good during the day. I still keep my eyes open to keep other things from
running into me (or me running into them).

I am installing a collision avoidance system in my motorglider, but it
depends upon the other aircraft having a transponder - not much good with
the glider circuit.

Colin


---
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Checked by AVG anti-virus system (http://www.grisoft.com).
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[Mark James Boyd]

>Seeing that you are going to be using Lawrence Welk's mirrored ball, you
>should also attach his perpetual bubble machine, and use it for thermal
>location.

We had a real blast yesterday tossing out rolls of toilet paper
and slicing them with the wings. Also seemed good for thermals.
Harder to see than a glider though.

There is reflective tape that I've used before on boats...


--

------------+
Mark Boyd
Avenal, California, USA

[henkelize]

Hi all

Thanks for all the replies. I would be lying if I said I got what I wanted,
but the time spent in replying is appreciated.

Henk Stander


"COLIN LAMB" > wrote in message
.net...
> Interesting question - to give a "sparkle" to make the glider more
visible.
>
> I have a mirror in my search and rescue pack. The survival mirror has
great
> range. Mirrors have been spotted 50 miles away. However, they need to be
> aimed. What you are proposing is to use an assembly that has multiple
> reflecting surfaces so that aiming becomes unnecessary.
>
> There are problems, however. As the surface number increases, the
> reflections are reduced in magnitude. Fortunately, the original source is
> substantial. A good mathematician could determine the probabilities of a
> reflection, knowing the number of surfaces, the various possible locations
> of the sun and the other aircraft and and the likely possibility of the
> other pilot looking into an area that might contain the glint.
>
> Some collisions are from below or above. The reflector would not do much
> good in those directions.
>
> If he (or she) has their head "in the cockpit", it will not be much good.
I
> fly a helicopter that has a strobe on all the time and it does not do much
> good during the day. I still keep my eyes open to keep other things from
> running into me (or me running into them).
>
> I am installing a collision avoidance system in my motorglider, but it
> depends upon the other aircraft having a transponder - not much good with
> the glider circuit.
>
> Colin
>
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.713 / Virus Database: 469 - Release Date: 6/30/04
>
>

[[email protected]]

On Mon, 12 Jul 2004 01:09:53 +0000, Gordon Schubert wrote:

> WHAT ABOUT REFLECTIVE TAPE?

'Reflective tape' is normally 'retroreflective' - it reflects light back
to where it came from.

This only works when whoever you want to see you is shining a bright
light at you - for example cycle reflectors are great at night, but
not much help in the daytime.

VNE

[Bob C]

How 'bout a disco ball helmet? That way you could
be seen even if you bailed out ;o)

I put Whelen strobes on my Salto for night flight and
night airshows. Took 6 months of paperwork and I had
to re-certificate in Experimental-Exhibition category.
On top of that, due to no generator, I'm restricted
to using the anti-collison lights only in Airshow Waivered
(sterile) airspace. Cost me a fortune, even though
Whelen donated the lights. Typical FAA!

Despite the limitations, I turn them on in crowded
air. (I dare them to try to bust me for that!) They
are the newer Whelen 'Comet-Flash lights. They fire
4 rapid pulses, 80 times/minute. They are easily visible
in full sunlight for quite a ways, and very bright
on cloudy days or at dusk.

BTW, ATC radar has no trouble picking us up. Give
them a call and ask them to give you headings for identification.
They'll have you make a couple of 90 degree turns
to identify your blip. After that, they'll know who/where
you are.





At 22:12 13 July 2004, wrote:
>On Mon, 12 Jul 2004 01:09:53 +0000, Gordon Schubert
>wrote:
>
>> WHAT ABOUT REFLECTIVE TAPE?
>
>'Reflective tape' is normally 'retroreflective' - it
>reflects light back
>to where it came from.
>
>This only works when whoever you want to see you is
>shining a bright
>light at you - for example cycle reflectors are great
>at night, but
>not much help in the daytime.
>
>VNE
>
>

[Eric Greenwell]

Bob C wrote:
> BTW, ATC radar has no trouble picking us up. Give
> them a call and ask them to give you headings for identification.
> They'll have you make a couple of 90 degree turns
> to identify your blip. After that, they'll know who/where
> you are.

When you say "ATC radar has no trouble picking us up", is it because of
the lights? If not, what is the ATC situation: near or inside Class B or
C airspace, inside the Mode C veil, traveling enroute, or? I'm curious,
because our local Class does have trouble picking us up, and I'm
wondering what the difference is.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Ray Lovinggood]

Eric,

The controllers at the Raleigh-Durham (RDU) airport
ATC facility can see my glider with their 'primary'
radar. RDU is within Class C airspace (wanting to
go to Class B, but that's another story) and one time
I called them up while thermalling and they found me.
They kept an eye on me when traffic was light. They
didn't have time to concentrate on looking at primary
returns all the time, but I could and did listen to
them so I could help determine where the traffic was
that they were speaking with. During this one particular
flight as I circumnavigated the RDU Class C airspace,
I always remained outside of the Class C, but was probably
no more than 40 - 50 miles from the control tower.

Ray Lovinggood
Carrboro, North Carolina, USA



At 04:36 14 July 2004, Eric Greenwell wrote:
>Bob C wrote:
>> BTW, ATC radar has no trouble picking us up. Give
>> them a call and ask them to give you headings for
>>identification.
>> They'll have you make a couple of 90 degree turns
>> to identify your blip. After that, they'll know who/where
>> you are.
>
>When you say 'ATC radar has no trouble picking us up',
>is it because of
>the lights? If not, what is the ATC situation: near
>or inside Class B or
>C airspace, inside the Mode C veil, traveling enroute,
>or? I'm curious,
>because our local Class does have trouble picking us
>up, and I'm
>wondering what the difference is.
>
>--
>Change 'netto' to 'net' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
>

[Tom Serkowski]

" > wrote in message >...
> On Mon, 12 Jul 2004 01:09:53 +0000, Gordon Schubert wrote:
>
> > WHAT ABOUT REFLECTIVE TAPE?
>
> 'Reflective tape' is normally 'retroreflective' - it reflects light back
> to where it came from.
>
> This only works when whoever you want to see you is shining a bright
> light at you - for example cycle reflectors are great at night, but
> not much help in the daytime.
>
> VNE

I think he's talking about silver mylar tape. S&G had an article
about visibility markings on sailplanes and the conclusion was that
covering the control surfaces with something like this was the best
bet. The surfaces are relatively flat and move around a bit, so
produce frequent 'glints'. Of course, only works in sunlight, and not
very well from the front. So best results are if the target is
circling away from clouds.

-Tom