Stealth bird

In article ,
Big John wrote:

Orval

The only thing that reflects radar is metal or things (like paint)
that have metal in them.


One of the Approach controllers I work with while flying jumpers can see
the open parachutes on the radar. There isn't much metal in a parachute
system.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

Big John wrote:

Some of the Stealth Birds are supposed to have a reflection equivalent
to a sparrow +/-.

That may be true, but I understand that some years ago they tracked a stealth
bomber completely across England based on the complaints of interference with
the cell/PSC phone service. Even as poverty-stricken as the Russian military is
these days, it wouldn't surprise me to find that they now have a cell-phone
transmission/pickup system that can track that plane real well.

George Patterson
Some people think they hear a call to the priesthood when what they really
hear is a tiny voice whispering "It's indoor work with no heavy lifting".

Remember that props are usually metal, as well as gear legs. Also, altitude
and direction relative to the radar site also will determine the quality of
a primary return.
"Big John" wrote in message
...
Dave

Your words brought back memories. TNX. Should have remembered.

I still think homebuilders can build a Stealth bird.

Some shielding like in the 117 might be an easy way to reduce return
from areas that are not 'glass'.

Big John


On Wed, 26 Nov 2003 17:06:41 -0500, Dave Butler
wrote:

Big John wrote:

I'm not up to speed on current traffic control radar and if they both
'skin paint' and look at transponder returns?.

What you're calling 'skin paint' is what ATC calls "primary radar". The
ATC
system that processes transponder returns is called "secondary radar",
also
known as ATCRBS (Air Traffic Control Radar Beacon System).

Both kinds of radar operate simultaneously and using antennas that rotate
together.

Occasionally you'll hear that either primary or secondary radar is out of
service at a particular facility. If secondary radar is out of service
they have
to use some other means of identifying the primary radar returns. If
primary
radar is out of service, they can see only transponder-equipped aircraft.

Remove SHIRT to reply directly.
Dave

Orval

I started this thread to get some to consider going stealth.

We used to fly T-33's as target aircraft and they were very hard to
'skin paint'. To increase the size of the return, we would hang a
'Luneberg Lens' underneath the fuselage to make the radar return the
size of a B-47 'primary radar' return.

I think it would be an interesting project to make a GA stealth bird
G

Big John


On Thu, 27 Nov 2003 03:43:59 GMT, Orval Fairbairn
wrote:

In article ,
Big John wrote:

Orval

The only thing that reflects radar is metal or things (like paint)
that have metal in them.

The biggest contributor to the return is the engine.

WAG is that a 1 square foot flat plate might be close to equivalent
area reflecting radar if plan built?

A bird built for minimum return might even be less.

Some of the Stealth Birds are supposed to have a reflection equivalent
to a sparrow +/-. GA might get close to that with some special radar
absorbent paint, etc. ?

Big John

It depends -- if there is a Doppler component, it can reflect radar --
even a baseball does. Every cable, antenna, pushrod, etc. will reflect
radar -- especially if it is multiples of quaeter-wavelengths. That is
the principle of chaff. As I posted, it would take some effort to make
a really stealthy plane.



On Wed, 26 Nov 2003 21:35:35 GMT, Orval Fairbairn
wrote:

In article ,
Big John wrote:

Just some ramblings on stealth.

When the Air Defense Command was in high gear with Radars all over the
States and over lapping coverage, we used 'skin paint' (vs beacon/IFF
or transponder) to located and track aircraft (we didn't think the
Russians would come in squawking for us). The FAA always used
beacon/transponder to make a large blip on their scope for traffic
control purposes.

With that background, what does FAA use today? If they do not use
'skin paint' why can't the 'glass' birds with a wooden prop, turn off
their transponder and fly through all the restricted areas unseen?

I'm not up to speed on current traffic control radar and if they both
'skin paint' and look at transponder returns?.

Anyone want to comment on this thread and expand?

Big John

There is still a fairly large RCS, even on a glass bird -- engine,
pilot, electronics, wiring, antennae, landing gear, etc. It would take a
lot of expertise to get the RCS down to stealth levels.

In article ,
Big John wrote:

Orval

The only thing that reflects radar is metal or things (like paint)
that have metal in them.

The biggest contributor to the return is the engine.

WAG is that a 1 square foot flat plate might be close to equivalent
area reflecting radar if plan built?

A bird built for minimum return might even be less.

Some of the Stealth Birds are supposed to have a reflection equivalent
to a sparrow +/-. GA might get close to that with some special radar
absorbent paint, etc. ?

Big John

It depends -- if there is a Doppler component, it can reflect radar --
even a baseball does. Every cable, antenna, pushrod, etc. will reflect
radar -- especially if it is multiples of quaeter-wavelengths. That is
the principle of chaff. As I posted, it would take some effort to make
a really stealthy plane.



On Wed, 26 Nov 2003 21:35:35 GMT, Orval Fairbairn
wrote:

In article ,
Big John wrote:

Just some ramblings on stealth.

When the Air Defense Command was in high gear with Radars all over the
States and over lapping coverage, we used 'skin paint' (vs beacon/IFF
or transponder) to located and track aircraft (we didn't think the
Russians would come in squawking for us). The FAA always used
beacon/transponder to make a large blip on their scope for traffic
control purposes.

With that background, what does FAA use today? If they do not use
'skin paint' why can't the 'glass' birds with a wooden prop, turn off
their transponder and fly through all the restricted areas unseen?

I'm not up to speed on current traffic control radar and if they both
'skin paint' and look at transponder returns?.

Anyone want to comment on this thread and expand?

Big John

There is still a fairly large RCS, even on a glass bird -- engine,
pilot, electronics, wiring, antennae, landing gear, etc. It would take a
lot of expertise to get the RCS down to stealth levels.

"Big John" wrote in message
...

Just some ramblings on stealth.

When the Air Defense Command was in high gear with Radars all over the
States and over lapping coverage, we used 'skin paint' (vs beacon/IFF
or transponder) to located and track aircraft (we didn't think the
Russians would come in squawking for us). The FAA always used
beacon/transponder to make a large blip on their scope for traffic
control purposes.


Not always. Radar was used by ATC for some years prior to Project Beacon in
the early sixties. Transponders didn't become the rule rather than the
exception for a few more years.



With that background, what does FAA use today? If they do not use
'skin paint' why can't the 'glass' birds with a wooden prop, turn off
their transponder and fly through all the restricted areas unseen?

I'm not up to speed on current traffic control radar and if they both
'skin paint' and look at transponder returns?.

Anyone want to comment on this thread and expand?


ATC primary radar isn't all that good, especially in the Centers. Some
radar sites have beacon interrogators only, no primary radar at all. As you
say, for ATC purposes aircraft want to be seen and the vast majority have
transponders. Broadband radar provided better primary targets, but a lot of
clutter as well.

"Orval Fairbairn" wrote in message
news

There is still a fairly large RCS, even on a glass bird -- engine,
pilot, electronics, wiring, antennae, landing gear, etc.


Not on ATC radar there ain't.

"Big John" wrote in message
...

The only thing that reflects radar is metal or things (like paint)
that have metal in them.


Then how does weather radar work?

"Big John" wrote in message
...
Orval

I started this thread to get some to consider going stealth.

We used to fly T-33's as target aircraft and they were very hard to
'skin paint'. To increase the size of the return, we would hang a
'Luneberg Lens' underneath the fuselage to make the radar return the
size of a B-47 'primary radar' return.

I think it would be an interesting project to make a GA stealth bird
G

I would think that just as Stealth technology has advanced over the years,
that so to has radar technology advanced. So, where in the past radar could
get a return from something size "X" now it should be able to capture and
enhance the same return from something much smaller.

Of course as greedy American corporations keep out-sourcing engineering jobs
to India and China we can soon expect those countries to start making
significant gains in military technology at our expense.

Earl G.

good question.. weather radar tracks water.. imagine that.. stronger returns
means more water means a bigger storm

we used to track migrating birds with ATC primary "skin paint".. especially
in flocks.. like the "Flying V" duck formations..

the radar was reflecting off the water in the ducks bellies.., this was
confirmed when "multiple traffic" was called to an aircraft.. "type and
altitude unknown", and the response from the pilot was... "nothing over
there but a flock of ducks heading south along the river"

BT

"Steven P. McNicoll" wrote in message
hlink.net...

"Big John" wrote in message
...

The only thing that reflects radar is metal or things (like paint)
that have metal in them.


Then how does weather radar work?