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Locating OAT Probe / Magnetometer


GrassStripFlyBoy

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Planning panel upgrade, not entirely committed to the brand of EFIS but leaning very heavily towards the GRT Avionics Sport EX, have the layout in panel mostly sorted, thinking beyond the panel I'm looking for guidance on a couple other aspects here.  OAT probe, I'm familiar with CTLS using the inspection plate under wing, probably makes sense to follow that but not excited about pulling wing.  So, how difficult is it to route wires out to that cover?  Second, is there a more friendly / alternate location to mount probe on a CTSW?  I could leave the probe out of the install until wing pull is needed down the road.  Remote magnetometer is suggested to be placed out towards wing tip or tail, what is the recommend location on these, issues with carbon fiber shielding it?  And might not do this as GPS course heading is primary nav guidance - thoughts there?

Thanks, Darrell

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I would pull the cover on the left side and look around. This is where they mounted the magnetometer, there may be a shelf there for mounting. I have not pulled wire out there, so not sure how hard it would be. I don't know if they already knew what equipment would be installed in the airplane when it was built, or if they provided a means for wiring if it was ordered with such equipment. When you have the cover off look for the nav light wiring. It might be able to be used as a method of pulling new wires.

That being said I know of after production installations of both. My first CT had the magnetometer installed in the baggage compartment on the tunnel. A pair of bag chairs in the baggage really messed with the heading. I didn't have an OAT. I have seen OAT mounted on the belly, but the exhaust cause incorrect temps. On the side of the fuselage up under the flap is another place I have seen them installed. That would be my choice if not going to the inspection cover.

Also the magnetometer provides information to the computer to compute crosswind and headwind component if you EFIS has that capability.

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Darrell, here is a picture that you can just make out the OAT probe at the very bottom right corner. I have not seen any variation in temps due to exhaust, but it’s also slightly hiked up from the “belly”, I’d estimate about a foot up from belly’s bottom.  As far as the magnetometer I have not located it yet but can tell you mine is not mounted in the wing nor in the baggage compartment. I believe it is mounted in the center tunnel under the baggage area as I see the wires leaving the panel, ducking under the center tunnel but not coming out the baggage are. I’ll admit I didn’t spend much time looks as I only wanted to make sure it was not located in a place that would have interference20337FD9-C1F4-48F9-B9C1-A40E840D127A.thumb.jpeg.5b3fbb0fcd49891573479ccc3717947a.jpeg 

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Thanks for the details fella's.  I was eyeballing that upper fuse by flap area, and will nose around more based on thoughts here.  Lower fuse would be convenient but even if exhaust is clear I'd think there is still heat coming from bottom cowl opening, higher up seems like cleaner air location.

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My plane did not have a D100 from the factory, it was installed by the dealer in Minden, NV. They installed the probe about the same offset from centerline as johnnyjr's only toward the rear of the baggage compartment. I can tell you that was not a good place to put it. By the time I had enough of bad readings the western dealer was out of business and their avionics man had a terminal experience in his Baron.

So, I put a new probe on the side of the fuselage just under the right wing making sure it would stay shady, be clear of the flaps, and be accessible from the inside high up in the baggage compartment. Works great! And it's simpler then putting it on the underside of the wing out by the inspection hole.

Don't put it on the belly. My 2 cents.

 

 

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