"lonewulf" <rengaw@swissonline.ch> wrote in message

the
also
Sound
sound

You are correct, Oskar. This is shown very clearly in the graph: Speed of
Sound vs Altitude in the link:
http://www.digitaldutch.com/atmoscalc/index.htm

I guess most of us are considering the 0 to 36,000ft range where most
aircraft fly.
Above that, as you state, the speed of sound is constant to the outer edge
of the troposphere then is rather erratic.
But then this is the province of rockets, not conventional aircraft.

in

Don't be sorry - I have expanded my knowledge as well!

Cheers,
John