You need to know the outside air temperature when you are flying an airplane. That lets you accurately calculate your airspeed and determine whether the mist or rain you are flying toward will stay liquid or coat your wings with ice. To get an accurate reading, the outside air temperature (OAT) probe should be located away from the engine exhaust and out of direct sunlight. I decided to put it under the tail of my Bede BD-4C airplane.
The tail is farther away from the exhaust than strictly necessary but this location has a big access panel. Should I ever need to replace the probe, it will be easy to do so.
I ran a wire the length of the plane.
This is proof that if you throw something away, you will definitely need it. I had had a nice 3/8″ vinyl tube running through this exact spot… just in case I ever wanted to run a wire to the tail of the plane. The front end of the tube was in the way when I installed the autopilot servo (the black box in the top, left corner of that photo) so I removed the tube. Guess what… it would have been a perfect place to run this wire.
Back in the tail, I drilled a small hole through one of the angles, installed the OAT probe, and sealed it up with some RTV to be sure that the nylon nut does not come loose.
When I fired up the EFIS, several weeks later, the probe worked. It precisely told me the temperature in the garage to the tenth of a degree Fahrenheit.
I put my probe in the NCAC vent I placed between the cowling and the door for cabin vents on each side. My probe was a flat disc and the diameter of a quarter and only about 1/4 thick Your installation sounds good. It should be protected there by the dorsal fin at the tie-down.
You’re getting close!