Mounting OAT probe

[danb35]

I'm looking at installing a Davtron M803 clock/OAT in my M20F, but I expect the same would apply to any Mooney, hence posting here.  I'm wondering about where to best mount the probe for the OAT.  I understand that, in general, under the wing works best, but for planes with this installed at the factory, where under the wing?  Wiring would be easier from the left wing, but I haven't found much guidance on the best place to mount it.  Thanks for any suggestions!

[MooneyMitch]

I installed the very same unit in the E model.   Davtron sent some specific mounting information with the unit.  I mounted the actual Davtron display on the right side of the instrument panel.  Without looking at the info. and just by memory, I installed the probe under the right wing about 2 feet out from the fuselage.  Wiring was very easy from that point.  Partially remove the front portion of the right side upholstery panel.  Remove the access panel on the wing, located next to the fuselage.  With that you'll be able to install the probe and also have visual and physical access to pull the probe wire through and up into the instrument panel area.    That's my experience anyway.   I hope this helps you too.  It's a rainey day here otherwise I'd be at the airport........maybe later!

[danb35]

I've checked out the stuff on Davtron's website (don't have the unit in hand yet), and it discusses how to mount the probe, but I don't see a discussion on where.  I'm planning on mounting the clock on the left panel, so I'd be mounting the probe under the left wing, but it sounds like the same idea.

[MooneyMitch]

I apologize, I have the Davtron 303 model.  I think the probe location discussion is the same either unit.  Maybe call Davtron tech. support and ask them about the suggested physical location of the probe.   I do believe that that info. comes in the box with the unit.  I'll look for my installation information too.   I would think mounting on the left side should be the same as far as interior panel and wing access panel and routing the wires.

[Awful_Charlie]

Wherever you choose, do make sure it is not downstream of the exhaust of the cowl outlets - the quantity of heat that comes from those regions, even when diluted, will introduce a gauge error you don't really want.

I have an OAT probe in the starboard NACA duct on the fuselage which seems to be ok, unless left in the sun.  The factory sender is way out on the lower side of the starboard wing between the outboard end of the fuel tank and the tank vent.

hth

Ben

[laytonl]

On our 1978 M20J, it is out a couple of feet on the right wind in the center of an inspection cover.

Lee

[KSMooniac]

I installed a Davtron M655 OAT/multifunction instrument in my 201 a couple of years ago via a 337 field approval under supervision of my IA.  I put it in the left sub-panel at the original OAT location, and mounted the probe on an inspection panel on the lower side of the left wing, just outboard of the main gear.  This was a miror image of the factory probe location on the right wing.  Someday I plan to add another probe there and connect to my JPI or whatever upgrade primary engine monitor I choose in the future.  This location is shielded from the sun, exhaust, air heated by the cowling, and fingers/knees/legs, etc. so I think it is perfect.  It was not a major PITA to route the wires, and worth doing correctly IMO to get accurate readings.