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Re: Stealth
Posted:
Mar 2, 1995 9:42 AM
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On 2 Mar 1995, Joseph Frost wrote:
>
> One topic of geometry special to stealth aircraft is the diffuse reflection of
> radar waves that involves using flat surfaces angled away from the transmitter,
> continuous s-bends in leading edges that cannot be angled away, and radar
> reflective coatings on windows so that the pilot's helmets don't act like
> a beacon.
> ... stuff deleted ...
> Back to the Stealth technology. There was an article in Popular Science
> that had some information about the way the stealth works, and there is
> an article published by a Russian in the 60's that was the original source
> of the ideas. If you narrowed your project to simply showing the difference
> between the reflection from a rounded fuselage vs the reflection from an
> angular fuselage, you have the beginnings of a visually interesting project.
>
> A strong light and a light-meter could substitute for radar.
>
The reflective properties of the Stealth's Flat surfaces brings up a
related question that intregued me when I first learned how the stealth
worked. As Joseph Frost Points out the Stealth is "invisible" to radar
because it has flat surfaces rather than curved ones. Living in
Boeing-land (as Jim King points out) we are exposed to things that fly.
But we are also exposed to things that swim. One every navigational bouey
and nearly every boat that floats around in Puget sound there is a metal
octahedron. Now these are no ordinary octahedra because they do not
contain the usual triangular faces. Instead they contain the 3
diametrical squares. In an xyz-coordinate system with the origin at the
center of the octahedron the squares are on the 3 coordinate planes (xy-
xz- and yz-planes). I once asked what these were for, and was told that
they were for radar. Apparently they show up very sharply on radar.
So the question arises as to why the flat surfaces of the Stealth bomber
make that airplane hard to detect by radar but the flat surfaces of the
Navigational octahedra make these objects easy to detect by radar. One
would think that all the boats and boueys should be equipped with metal
spheres. But the octahedra are better.
I know the answer why this works (so you people don't need to e-mail me
with an explanation). It just seemed that if a student were going to
look into the reflective properties of curved and flat surfaces this is
another aspect of the same question.
Will Webber
University of Washington
Boeing-land WA
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