BEST OAT SENSOR LOCATION

[DCarlton]

I know this has been asked many times but I didn't have any luck searching.  Where are most folks mounting their OAT sensors?  I'd like to mount one on the left wing (I think).  I have one on the right side inlet duct but it reads a little high due to engine heat.  The new one will support an AV-30C.  Thanks.  

[C.J.]

Right wing just outboard of MLG.

[PT20J]

Mooney mounted the one on my M20J under the right wing on an inspection cover outboard of the fuel tank. Left, right, can't imagine it matters.

[McMooney]

I have one in each of the inlet ducts,  they seem to be pretty accurate., match the thermometer in the windshield

[Ragsf15e]

My jpi sensor is on the first inspection panel, forward left wing.  It seems to be very accurate there.

[N201MKTurbo]

Mine is on the left wing.

There is only one temperature that matters, 0 deg C. You can tell it is right when the ice starts forming at -0.1 and starts to melt at 0.1 deg C.

I’ve had my Davtron OAT for about 20 years. Haven’t got much ice in those years, but every time I did, the OAT was spot on.

[laytonl]

47 minutes ago, Ragsf15e said:

My jpi sensor is on the first inspection panel, forward left wing.  It seems to be very accurate there.

Same for me.  Factory OAT was in right wing, Jpi OAT is in left wing, first inspection panel.  Not too difficult to run the wires.  Lee

[PeteMc]

1 hour ago, DCarlton said:

but I didn't have any luck searching

Yea the Search function here is not very good.  I've been reminded a few times (sorry now I'm blanking on who told me) to just do a Google search, but for here.  So I just stuck in "OAT Sensor: mooneyspace.com" and came up with:

https://mooneyspace.com/topic/42326-oat-probe-location/

[RoundTwo]

I’m a member of the left wing club and it reads about 5° cooler that the JPI probe in the right cabin scoop. 

[bcg]

Mine are in an access panel in my left wing. They both read the same and both are a few degrees cooler than the analog gauge in my windshield that gets full sun.

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[DCarlton]

13 hours ago, RoundTwo said:

I’m a member of the left wing club and it reads about 5° cooler that the JPI probe in the right cabin scoop. 

Yep.  My JPI reads about 4 deg high in the right scoop.  
Thanks all for the responses.   Left wing in an inspection panel area the new one shall be.  

[Aerodon]

15 hours ago, RoundTwo said:

I’m a member of the left wing club and it reads about 5° cooler that the JPI probe in the right cabin scoop. 

You can calibrate the JPI OAT in the setup menu.

 

Aerodon

[PT20J]

You want the most accurate placement if you have air data computers feeding data to your panel because the ADC takes the total air temperature (TAT) measured at the probe and converts it to OAT (by subtracting the calculated ram air temperature rise) and uses this value to compute TAS. If the probe is reading higher because it is picking up engine heat it will throw the TAS calculation off slightly.

For icing considerations it would be more appropriate to display TAT (sometimes also called Ram Air Temperature, RAT) but Garmin (I don't know about others) displays the calculated OAT. At Mooney speeds it doesn't make a lot of difference because the TAT is only a percent or two higher than the OAT. But you are seeing a slightly lower temperature displayed than the airframe is experiencing.

[Ragsf15e]

I said mine was on the inspection panel, but I just looked at it, and it is just aft of the inboard forward left wing inspection panel. It’s easy to reach inside that inspection panel and still use the inspection panel. Maybe easier than actually mounting it on the inspection panel plate.

[DCarlton]

Anyone know if the old thermometer probe stuck through the windscreen can be removed if I have two digital OAT gages (EDM730 and AV30).  What paper trail would allow you to remove it?  On one hand it keeps my cover on; on the other hand it keeps my cover on.  I’d definitely like it removed if I install a new windscreen.  Thanks. 

[MikeOH]

23 minutes ago, DCarlton said:

Anyone know if the old thermometer probe stuck through the windscreen can be removed if I have two digital OAT gages (EDM730 and AV30).  What paper trail would allow you to remove it?  On one hand it keeps my cover on; on the other hand it keeps my cover on.  I’d definitely like it removed if I install a new windscreen.  Thanks. 

Hmm, interesting question as my OAT (in the pilot's side window) was removed by the PO when he installed the digital OAT.  I don't recall anything in the paperwork even mentioning it, though I wasn't specifically looking for 'removed old OAT'. My first question is if an OAT is even required by the TCDS?  If not, it seems you could remove it without issue.

[EricJ]

1 hour ago, DCarlton said:

Anyone know if the old thermometer probe stuck through the windscreen can be removed if I have two digital OAT gages (EDM730 and AV30).  What paper trail would allow you to remove it?  On one hand it keeps my cover on; on the other hand it keeps my cover on.  I’d definitely like it removed if I install a new windscreen.  Thanks. 

I'd think it'd be a minor alteration to take that out with a logbook entry.   It weighs less than a pound, so won't affect WnB.    As always, though, your IA has the opinion that matters.

[Ragsf15e]

15 hours ago, DCarlton said:

Anyone know if the old thermometer probe stuck through the windscreen can be removed if I have two digital OAT gages (EDM730 and AV30).  What paper trail would allow you to remove it?  On one hand it keeps my cover on; on the other hand it keeps my cover on.  I’d definitely like it removed if I install a new windscreen.  Thanks. 

I had an IA remove my unicorn horn about 9 years ago.  That part is simple.  Make sure you have a plan to fill the hole. There is guidance in the appropriate maintenance regulations for windshield repair. My IA just filled it with silicon. My new IA has not complained about it and it has held up just fine, but that is not in accordance with the directions.