Subject: Re: swift speed
Date: Jun 9 12:09:47 1994
From: Skip_Russell at intersolv.com - Skip_Russell at intersolv.com




>>seems that one might be able to measure their speed simply be recording
>>the sound as they fly by, and measuring the Doppler shift?
>

Mike Patterson replied:
>An interesting experiment. You would need:
>
>average sound frequency for a swifts wings (a)
>average shifted frequency for approaching swifts (s)
>speed of sound (apprx 340m/s)
>
>velocity of swift = -340((s/a)-1)

I think it's even simpler than that. Since you have the frequency made
by departing swifts (s1) in addition to approaching swifts (s0), you
don't need to measure anything else at all. Everything you need is on
the sonograph. I.e.:

velocity of swift = 340/4(s1/s0 - s0/s1)

If my math is right.

Skip
--
Skip_Russell at intersolv.com
Aloha, Oregon