On Mon, 07 Mar 2005 11:34:32 -0500, T o d d P a t t i s t wrote:

John Giddy wrote:

The altimeter doesn't need to be connected to a static port unless you
plan on pressurising your glider ;-)

Recognize, however, that opening the window or vent, etc.
can vary your indicated altitude by a few hundred feet, not
to mention any regulatory compliance issues in your country.

Would need to be a very well sealed cockpit to show such a change in
pressure IMHO. I have never seen such a change, but I have seen ASI
errors of 5 or so knots (say 10 km/hr) with window/vent operation.
Compliance issues are not a problem in Australia.
Cheers, John G.