"jharper aaatttt cisco dddooottt com" "jharper aaatttt cisco dddooottt
com" wrote in message news:1105391055.635118@sj-nntpcache-3...
....
Do
altimeters for higher altitudes have some kind of clever
mechanism to deal with the non-linearity of pressure at higher
altitudes.



I am not an expert in the mechanics of barometer/altimeter construction, but
I do not see that it has to be particularly clever.

Typically, the metal "can" (which expands and contracts with air pressure)
is preloaded with a steel-spring against the air pressure. Isn't the force
produced by a steel-spring typically non-linear throughout its expansion...
so could not the spring-steel parameters be chosen such that the
non-linearity matches air pressure non-linearity closely?