Re: air speed measurement above mach 1

Raul Ferreira <1@xxxxx> wrote:
> On Sun, 24 Jul 2005 17:24:03 +0000 (UTC), jimp@xxxxxxxxxxxxxxxxxxxx
> wrote:

> >Raul Ferreira <1@xxxxx> wrote:
> >
> >> What air speed would an observer (like a fighter pilot) measure if he
> >> is already above the air speed barrier?
> >
> >There is no such thing as an "speed barrier".
> >
> >> Could he possibly measure that speed at all?
> >
> >With the air speed indicator hooked to the pitot tube.
> >
> >> With what?
> >> By the same manner that air speed is measured by an observer at rest?
> >
> >An observer at rest WRT the air has zero air speed.
> >
> >http://travel.howstuffworks.com/question597.htm
> >
> >http://www.grc.nasa.gov/WWW/K-12/airplane/pitot.html
> >
> >http://www.allstar.fiu.edu/aero/PSSI.htm

> With these sources, airspeed is easy to measure.

> Now if this fighter pilot decides to measure the speed of SOUND
> instead of airspeed?

Then we would yank his license for gross stupidity.

> The speed of sound is given by Mach 1, right?

Sort of; Mach 1 is a velocity in air dependent on air pressure, temperature
and humidity. It is not an absolute number.

> And this speed (of sound) is measured by an observer at rest on
> ground. How?

The same way you would measure the speed of anything; time it over a
known distance.

> Can a fighter pilot measure the speed of sound if he is already
> travelling above that speed?

Measure the speed of sound where? The speed of sound is dependent on the
properties of the medium it is in. You want the outside air speed of sound,
the inside air speed of sound, or the speed of sound through the fuselage?

--
Jim Pennino

Remove .spam.sux to reply.
.

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