A major portion of 'stealth design' is to deflect the radar signal in
directions away from the transmitter [i.e. deflect the echo]. Hence, the
many flat panels on the F-117.

A secondary feature of the design is absorbent material.

A third feature is the hex filter designs in the windows/turbine
aperture etc [allow rf in but keep it from getting out].

But, your basic absorbing material is found in numerous graphite epoxies
whose composition is classified.

You may find useful information on basics by checking out 'space cloth'.
Space cloth is used for radar dummy loads and is available in Zo that
provide VSWRs from 5:1 to 1:1. At 1:1 there is no reflection.

Frank Alforo wrote:

Anybody have any info the material used on the stealth aircraft to absorb
radar signals?

Dave wrote:

A major portion of 'stealth design' is to deflect the radar signal in
directions away from the transmitter [i.e. deflect the echo]. Hence, the
many flat panels on the F-117.

A secondary feature of the design is absorbent material.

A third feature is the hex filter designs in the windows/turbine
aperture etc [allow rf in but keep it from getting out].

But, your basic absorbing material is found in numerous graphite epoxies
whose composition is classified.

You may find useful information on basics by checking out 'space cloth'.
Space cloth is used for radar dummy loads and is available in Zo that
provide VSWRs from 5:1 to 1:1. At 1:1 there is no reflection.

I read somewhere that the absorbant material had an impedance of 377 ohm per
square. J Kraus showed that space cloth of this impedance reflects 30
percent of the incident wave.
Is space cloth still manufactured? A google search turned up zero hits.

Tnx es 73, Frank

Frank Alforo wrote:

SNIP

I read somewhere that the absorbant material had an impedance of 377 ohm per
square. J Kraus showed that space cloth of this impedance reflects 30
percent of the incident wave.
Is space cloth still manufactured? A google search turned up zero hits.

Tnx es 73, Frank


I last purchased 'space cloth' [122 ohm/square] in 1990. I don't know if
it's still manufactured.

W1MCE

Frank Alforo wrote:
"J. Kraus shower that space cloth of this impedance reflects 30 percent
of the incident wave."

There must be an impedance discontinuity. Not 377 ohms?

Kraus said sheets of space cloth backed by a reflecting plate are
sandwiched between plastic layers. Kraus has an appendix "D" on
absorbers.

Searching on "Salisbury screens" got me 4578 hits.

Best regards, Richard Harrison, KB5WZI

I think someone would be in a lot of trouble if you find the recipe for
a specific stealth aircraft on the Internet. The "spacecloth" mentioned
in another post could be similar to Echosorb, a popular microwave RF
absorbent material that is available in sheet form. It ranges from a
1/16" thick pliable rubber to thicker, multilayer foam that looks like
the black antistatic foam used to ship IC's and other semiconductors.

Frank Alforo wrote:
Anybody have any info the material used on the stealth aircraft to absorb
radar signals?

On Mon, 29 Mar 2004 07:08:02 GMT, Mike wrote:
Echosorb, a popular microwave RF
absorbent material that is available in sheet form. It ranges from a
1/16" thick pliable rubber to thicker, multilayer foam that looks like
the black antistatic foam used to ship IC's and other semiconductors.

Hi Mike,

It is also quite heavy which would be inappropriate for aviation
applications. I played with this stuff a dozen years ago when one of
my buddies got a speeding ticket in his 'Vette. He asked me to design
a stealth bra for his ride - it didn't seem to be practical for any of
several reasons.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
It is also quite heavy which would be inappropriate for aviation
applications. I played with this stuff a dozen years ago when one of
my buddies got a speeding ticket in his 'Vette. He asked me to design
a stealth bra for his ride - it didn't seem to be practical for any of
several reasons.

Why didn't he just put aluminum foil on his hubcaps like everyone else? :-)
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 29 Mar 2004 12:14:27 -0600, Cecil Moore
wrote:
Why didn't he just put aluminum foil on his hubcaps like everyone else? :-)

Do they sell Vettes with steel wheels and hubcaps in Texas?
Do you wear your Levis tucked in your boots or outside them?

Richard Clark wrote:
Do you wear your Levis tucked in your boots or outside them?

I'm not allowed to wear boots. I don't own any cows.
--
73, Cecil http://www.qsl.net/w5dxp



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"Richard Clark" wrote
Mike wrote:
Echosorb, a popular microwave RF
absorbent material that is available in sheet form. It ranges from a
1/16" thick pliable rubber to thicker, multilayer foam that looks like
the black antistatic foam used to ship IC's and other semiconductors.

Hi Mike,

It is also quite heavy which would be inappropriate for aviation
applications. I played with this stuff a dozen years ago when one of
my buddies got a speeding ticket in his 'Vette. He asked me to design
a stealth bra for his ride - it didn't seem to be practical for any of
several reasons.

I was going to paint a whole-car with the RAM-paint used on my submarine
masts. Until I saw the price. Cheaper to pay the tickets ;-)

Jack