Re: Speed of sound at altitude and temp

[David Dockstader <DRDOCK00@UKCC.UKY.EDU>]

Why do you suggest that the value I read from the graph is incorrect?
I presume the equation you give is for sea level and there is no reason
to expect it to give the correct answer for 35,000 feet is there?

On Tue, 15 Jul 1997 00:33:54 brian whatcott said:
> As you can see, David Dockstader read a graph value from his CRC C&P
> which is markedly at variance with the expected value for -62degF
>
> As my 32nd edition seems to offer a reasonable value, I can only hope
> that the typo (?) was caught in editions after the 48th...
>
> Regards
> brian whatcott
>
>
> At 00:20 7/15/97 EDT, David Dockstader wrote:
> > The formula Brian gives addresses temp, but not altitude.
> > I looked up speed of sound in the index of my CRC Handbook of Chem & Physic
> > (48th ed, hopefully in newer ed too) and found a neat graph of the speed of
> > sound vs altitude for the real earth (I assume this is empirical but am not
> > sure of this) At 35,000 ft it is 335m/s.  Interesting related graphs are
> > Mean free path vs altitude and Collision Frequency vs Altitude.
> >
> >
> > On Sat, 12 Jul 1997 12:19:15 brian whatcott said:
> ...
> > > Enc Brit ( 14th edition, "sound") offers this empirical formula:
> > > c = 331.3 x root(1 + t/273)
> > >
> > > c in meters/sec, temp in degC
> > >
> > > This is c = 741 x root(0.935 + 0.002t)
> > >
> > > c in mph, t in degF
> > > ...
>
> brian whatcott <inet@intellisys.net>
> Altus OK