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- Path: sparky!uunet!mcsun!uknet!root44!hrc63!mrcu!paj
- From: paj@uk.co.gec-mrc (Paul Johnson)
- Newsgroups: sci.physics
- Subject: Re: Blue hawks (was Blue Sky)
- Message-ID: <1852@snap>
- Date: 27 Jul 92 15:43:14 GMT
- References: <BrrMJB.Brv@acsu.buffalo.edu> <1992Jul22.145723.24741@galois.mit.edu> <9930@sun13.scri.fsu.edu> <10018@vice.ICO.TEK.COM>
- Reply-To: paj@uk.co.gec-mrc (Paul Johnson)
- Organization: GEC-Marconi Research Centre, Great Baddow, UK
- Lines: 27
-
- In article <10018@vice.ICO.TEK.COM> hall@vice.ICO.TEK.COM (Hal Lillywhite) writes:
-
- >And I find it peculiar that although there are blue birds, there are
- >no blue raptors that I know of. Can you imagine the advantage a sky-
- >blue hawk would have? His prey would have a very difficult time seeing
- >him until it was too late. I wonder why such an obvious advantage
- >seems not to have developed.
-
- Because it doesn't work. No matter what you paint the underside of an
- aircraft, it still gives you a silhouette against the sky because the
- sky is brighter than the illumination of the underside of the
- aircraft.
-
- Experiments in camauflage have been done which involve putting lights
- on the underside of aircraft in order to match the sky. This works,
- and was (as I recall) used in the second world war by anti-submarine
- aircraft. Then the invention of radar made the whole matter moot.
-
- Active illumination is not an option available to eagles.
-
- Paul.
-
- --
- Paul Johnson (paj@gec-mrc.co.uk). | Tel: +44 245 73331 ext 3245
- --------------------------------------------+----------------------------------
- These ideas and others like them can be had | GEC-Marconi Research is not
- for $0.02 each from any reputable idealist. | responsible for my opinions
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