Re: transparent society fans take note

From: Doug Jones (
Date: Mon Apr 24 2000 - 00:17:03 MDT

Til Eulenspiegel wrote:

> > Heh... close to twenty years ago, when I worked at Otrona (a
> > portable microcomputer manufacturer) our production building was
> > plagued with flies from a nearby agricultural area. A bunch of us
> > brainstormed a flyzapper that would use microphones to triangulate
> > on a target, with an elliptic dish and a spark gap at the near
> > focus. Track the target until it crosses the range gate, then blow
> > its wings off with the focused SNAP of the spark gap...
> >
> I don't quite understand. If the spark gap lies at the near
> focus, what good is an elliptical dish? The fly must reach the near
> focus for a kill, but then why have microphones? Please explain this
> differently. Off-list is fine.

The spark gap is at the _near_ focus of the ellipsoid, and the hapless
fly is at the _far_ focus. The f-number has to be fairly low, less than
4 or so, but the overpressure from the spark can be delivered to the
target fairly well... provided you track the target in its random flight
until it passes through the far focus.

CO2 powered BB pistols (with no BBs) destroy insects as much as six
inches from the muzzle, and horseflies make great batting practice in
the mountains of Colorado at 9000 feet because their flight ceiling is
about 9600 feet on a summer day, and they have to "idle the engines" for
several minutes before they can lift off.

I had time on my hands when I lived out in the boonies, ok?

Doug Jones
Rocket Plumber, XCOR Aerospace

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