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Article #8403Re: Supersonic aircraft and noise pollution
From: Jack Zeiders
Date: Thu, 26 Jan 1989 21:29
Date: Thu, 26 Jan 1989 21:29
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> hpscdc:sci.space / roberts@CMR.ICST.NBS.GOV (John Roberts) writes: >Surely an SR-71 at surveillance altitude doesn't sound too loud from >the ground - that would spoil the surprise (:-) At Beal AFB last fall the SR-71 made a speed run at Mach 3 or so at altitude. The pilot dumped fuel creating a visible contrail, if he had not there would be little chance of seeing the aircraft as the altitude was reported as 60k feet. I had a 1000mm lens and could not see the black aircraft. Perhaps this was because of the ground glass focusing screen. The sonic 'boom' was a muted pop-pop that could go easily unnoticed if you were unaware of it. At take off the SR-71 is very noisy, The 'A' models apparently somewhat more so. Jackz
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!attcan!uunet!lll-winken!ames!haven!purdue!decwrl!hplabs!hpda!hpcuhb!hpscdc!jackz From: jackz@hpscdc.HP.COM (Jack Zeiders) Newsgroups: sci.space Subject: Re: Supersonic aircraft and noise pollution Message-ID: <3870008@hpscdc.HP.COM> Date: 26 Jan 89 21:29:29 GMT References: <8901240814.AA07708@cmr.icst.nbs.gov> Organization: Hewlett-Packard, Santa Clara Div. Lines: 15