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AFS temperature probe 'twofer'

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rv7charlie

Well-Known Member
Supporting Member
Joined
Nov 17, 2014
Messages
5,259
Location
Pocahontas MS
Just in case there are any AFS EFIS users on the forum, here are a couple of tips for the earlier (3000/4000 series) models.

I needed an additional OAT probe for the installation of an AF4500 in my RV6. The temperature probe costs around $70 from AFS; I wanted something a little less expensive. While some other brands/models use simple NTC or PTC resistive devices which can be as cheap as a dollar or so, the AFS models in question use a 'current source' device. After a little 'speculative' research, I took a flyer at buying a couple of Analog Devices AD590 devices. It's a lot more expensive; I paid just over $20 for two of them, delivered.
I plugged one into the same point as my AFS temp probe, and the resulting reading was within 2 degrees C of the AFS probe. Note that this is a new install of an AFS AF4500, and neither device had been calibrated in the 4500's setup menu, so I fully expect the AD590 to be as accurate as the AFS probe.

Here's a pic of the AD590 next to the AFS probe.
2nd tip: several RV drivers, including a friend of mine, have discovered that if you mount the temp probe inside the empanage fairing, above the horizontal stab 'deck', the temp readings are quite accurate and there's no need to have another thing poking out in the slipstream, costing at least 0.07 knots. (And simplifying wire runs.)
 

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