Dear Uncle
If your altimeter changes indications when you open the vent, that
indicates your altimeter is not connected to STATIC. Best to check
you plumbing.

Guy Acheson, "DDS"



On Jul 30, 9:16�am, Uncle Fuzzy wrote:

Sounds plausible to me, but what do I know? �I DO know that at 70
knots, opening the vent in my Speed Astir (AKA the 'Grob Solar Sauna)
will drive the altimeter down 100' instantly, so there is positive
pressure