The static needs to be outside, even if its not the most ideal pressure point because in flight there will be significant differences in pressure from inside and outside the aircraft. For VFR aircraft it typically does not show up as being that significant, but for flying IFR you can be off as much as 200 feet, and on approaches this could make a BIG difference! Wanting my aircraft to read as accurate as possible I installed a static port halfway between the canopy opening and the firewall, figuring that should give similar accuracy as the Cessna since theirs is located in a similar spot. It will definitely be more accurate than cabin pressure which is guaranteed to be off compared to true static. Remember this effects all instruments that use static input, that means airspeed and altimeter, and if you use one the vertical speed indicator, as well as the Mode C encoder for those who have one.
Colin & Bev Rainey KR2(td) N96TA Sanford, FL crain...@cfl.rr.com or crbrn9...@hotmail.com http://kr-builder.org/Colin/index.html