Passive Reflective Devices

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

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

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

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

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

"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

"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/...3DApplets.html

Pick your shape and have at it.

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.

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

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