After searching and posting on the forum seeking recommended locations to mount an OAT probe for an EFIS I have come across many options and recommendations. Many of them make sense such as to keep the probe away from the exhaust, away from cowl exit air, out of the sun, etc..
The one recommendation that GRT makes that I can’t wrap my head around is to keep it out of the prop wash. How would prop wash air that isn’t blended with engine exhaust or cowl exit air give a different reading than a probe mounted mid-span on the lower wing skin? I believe that several certified planes have their OAT probes sticking out of the corner of the windscreen which is in the prop wash. This also goes against the recommendation to keep it out of the sun. Perhaps once there is airflow over it the impact of direct sunlight is negligible?
So what is it about the prop wash that will give a bad reading and how far off is it likely to be?
The one recommendation that GRT makes that I can’t wrap my head around is to keep it out of the prop wash. How would prop wash air that isn’t blended with engine exhaust or cowl exit air give a different reading than a probe mounted mid-span on the lower wing skin? I believe that several certified planes have their OAT probes sticking out of the corner of the windscreen which is in the prop wash. This also goes against the recommendation to keep it out of the sun. Perhaps once there is airflow over it the impact of direct sunlight is negligible?
So what is it about the prop wash that will give a bad reading and how far off is it likely to be?