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Steve Sampson

Well Known Member
Just wondering where to put the OAT sensor. I am thinking either in the space behind the fuel tank in front of the spar, or in the space between the fuselage wall and the first wing rib. Would there be air movement in there? My assumption is yes, since without aileron boots there would be a draft, although that is behind the spar. Is the same area behind the spar preferable?.

Thoughts?
 
Steve,

I don't think it's necessary to locate the OAT inside the airplane at all (i.e., out of the draft). Air movement is OK, since OAT is not influenced by the "wind-chill" factor.

The instructions that came with both my Dynon and my Grand Rapids EFIS systems say to mount the OAT probe out of direct sun, and away from locations where it might be heated by the engine or exhaust stream. They prefer that you install it protruding from the bottom of the wing skin, outboard of the prop arc. (I've also seen them mounted inside the NACA fresh-air scoop on the side of the fuselage on many RV-8s.)

Hope that helps.
 
Do a search for "OAT" here on the forums - this has been discussed MANY times (and you'll get lots of different ideas....)
 
NACA=no, Wing Inspection Plate=OK

I had mine in the NACA vent and it's now certain that it reads too high in that location. Now it's just barely protruding about a 1/16" from the first inspection plate in the right wing. When comparing to ASOS, it seems to be right on, but it's hard to be sure because my hangar is heated and it takes a while for it to equalize and by then I am in the air and so on. If you can run a longer wire, th next panel further out would be better for being sure.
 
Hi Steve!
I put my AOA right in the surplus hole of the original Vans pitot tube, because I used the Dynon pitot, that needs a much bigger elliptic hole for mounting. As far as I can say, it reads perfect and you can follow your wiring along with the pitot lining right into the cabin.
 
Thanks for the various replies.

Dirk, I must have been short changed. VANS didnt ship me that hole!

The reason I wanted to be in a draft was so the air was NOT stagnant. I think I will start out in the wing/fuse gap. I can always move it if I find it is getting tangled with the exhaust heat.

I quite like the inspection plate idea but the wires would need to be longer!

Thanks.
 
Good Location

Steve,
I believe you're on the right track with the sensor inside the faired area ahead of the wing spar. I was told to mount it there while building my 6A and it worked great, so it's mounted there on the 4 as well.
Good Luck!
 
...LOL ;o)
Shipping holes would please that cheap Dutchman, I think....
In fact, it is the misdrilled hole for the original pitot tube I drilled per plans years before I decided to go with the Dynon. The only think I'm shure about is, that it will not work if you put the probe into the gear leg fairing. One RV-4 builder here has done it, resulting in way too high readings because of some funny airflow through the fairings from the inner cowl down to the wheel pants.
Steve, I hope to see you at the RV fly-in in Damme, Germany at the end of May or at Hogan?s, Sweden.
 
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