After trying several locations on the cowl of my 912s, I can definitively
say that the cowl is simply the wrong place if accuracy matters.
My first location was through the most foward duct plate under the gear box.
Despite
the probe being well insulated from behind, the OAT would be
up to 20F high in cruise flight
Next location was the lower stbd vent, on a plate under the oil tank and
just next to my cold cabin air inlet for the scat hose. It sits at least 10F
high
in flight. There have been several other locations chosen so I did not need
a separate electrical connector for the temp probe in removing the
cowl. All off from OAT, all rising with engine start.
Once you fly, you will see anywhere under the fuse is a poor location by
examining the trail of exhaust soot. Likewise, top of fuse is problematic
due to sunlight. I think Kevin is on the right track.
A good location which is also convenient to wire and connect is not a trivial
exercise. I am still looking for a satisfactory location so that I can improve
the reliability of my flight test data with accurate Density Altitude.
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Ira N224XS
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