'Outside Air temperature' probe position

[John Tipton]

Has anyone fitted their 'Outside Air temperature' probe in the NACA vent, is this a good place, or not

 

[lr172]

lots of threads on that topic. Those that have measured after moving from that location say it reads almost 10* above ambient.

 

[RV7 To Go]

I have seen many that have put it there but have heard that it gives inaccurate readings in that location. I put mine, as many do, about 6" back of the leading edge and about 6" below the horizontal stab. Seems accurate in that location. FWIW.

 

[DanH]

Underside of the wing, outside the propwash.

 

[airguy]

I put mine in the Vans-standard location for the bent-tubing pitot tube - and then installed a Gretz mounted heated pitot for IFR work. The OAT is just the perfect size to fill that hole.

 

[Cth6]

I have 2 OAT sensors on my 9A. One is in the wing fairing, installed by the builder, and it is 8+ off. One in the middle of the last wing access panel, I installed with an AV-30 and it is spot on. One of these days I am going to extend the sensor in the wing fairing.

 

[DarylT]

Has anyone fitted their 'Outside Air temperature' probe in the NACA vent, is this a good place, or not

I did originally. seemed a bit higher due to engine heat. I res-positioned under the wing in the first inspection bay. Now my true airspeed is accurate. Worth the change.

 

[RV6_flyer]

I have one in each NACA vent on different sides of the fuselage. The one in the SUN always reads higher.

See Dan Horton's (DanH) post above on recommended location that I think they should be.

 

[RV8JD]

Here is what the Dynon SkyView manual says on OAT location:

"Sensor Location​

The SV-OAT-340 is an outside air temperature sensor. In order for it work properly, it must be able to measure air temperature accurately. Avoid exposing the sensor to sources of heat that would interfere with outside air temperature readings such as:​

• Direct sunlight
• Engine heat and exhaust
• Aircraft interior (back side of sensor)
• Heated air from the cabin exiting from an open window or cabin air exhaust port
• The installation area should have space for a nut and wires on the back side of the sensor. It is acceptable to extend or reduce the wire length if necessary. Reduce the wire length by cutting out the desired length from the middle of the wires and splicing together the remaining ends.
• If there is a backup ADAHRS in the SkyView system, it is acceptable to install a backup OAT sensor a few inches away from the primary sensor. Consider running primary and backup OAT sensor wiring together. Tape sensor wire pairs together to avoid confusion later."

Here is what Davtron says:

"NOTES: THE TEMPERATURE SENSOR MOUNTING SHOULD BE IN A PLACE THAT IS FREE OF EXHAUST GASES OR COWL FLAPS AIRFLOW. THE IDEAL PLACE IS TWO FEET OUT FROM THE WING ROOT ON THE BOTTOM OF THE WING. SENSOR LEADS MAY BE LENGTHENED OR SHORTENED WITHOUT AFFECTING CALIBRATION."​

FWIW, my RV-8 (IO-360-M1B) has a Dynon OAT probe on the aft fuselage under the right stab. A friend retrofitted a Davtron OAT probe (for an AV 30) for his RV-8 on the second outboard inspection panel of the left wing. We have compared OAT readings on several occasions when flying close together and they differ by 1°F at the most. I have heard anecdotally that the 'aft fuselage under the right stab' location does not work as well for RV's with larger engines (like those for the RV-10).

My RV-8:

My friend's RV-8:

 

[Davea320]

I put mine in the Vans-standard location for the bent-tubing pitot tube - and then installed a Gretz mounted heated pitot for IFR work. The OAT is just the perfect size to fill that hole.

Same