Could it be static error...maybe port location, or other?  Mine was off by 8 kts (reading low). A rework of the port to a domed one and my error is now 2kts low.  But, depending on your particular port issue if any, yours could be reading high.
Tim


On Aug 19, 2012, at 8:36 AM, jeffrey liegner <liegner@ptd.net> wrote:

> Recall my question (same subject) about the accuracy of OAT, and its efect on TAS and Winds.  SInce I rendere pireps including winds and OAT, the accuracy of this report is now in question.  Many have suggested reloacting the OAT to another place, different from the Lancair recommendation along the fuselage.  This is not an easy thing, putting the probe out on the wing, wiring coming into and through the wing root, into the pressure vessel (different from the current OAT location).
>
> I performed the flight TAS calculation recommended by several.  Whether three measurements with headings 120 degrees apart, or three orthogonal headings, the results are the same.
>
>
> The Chelton presents a TAS 216 and the calculator renders TAS 205 based on the n flight measurement.
>
> I wonder if I can change the compressibility quotient used by Chelton to adjust the OAT reading.
>
> Suggestions?
>
> Jeff L
> N334P
>
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