Cowl air temp probe

My engine monitor came with an extra air temperature probe that was supposed to be threaded into the side of a carb. Since I have don't have a carb, I'm thinking of installing it somewhere else in the engine compartment. The manual even suggests using it as a "cowl air temperature" probe.

So... The question to those of you who have been operating for a while and/or might have a similar setup... Where under the cowl would be the most useful place for an air temperature probe? Inside the plenum (on the back baffle)? Outside the plenum (near the top of the firewall)? Somewhere else?

In operation, do you frequently say, "It sure would be useful to know how hot/cold it is in location XX."??

Thanks for any advice or thoughts.

-Geoff
RV-8 almost done

[gmcjetpilot]

Originally Posted by Geoff

My engine monitor came with an extra air temperature probe that was supposed to be threaded into the side of a carb. Since I have don't have a carb, I'm thinking of installing it somewhere else in the engine compartment. The manual even suggests using it as a "cowl air temperature" probe.

So... The question to those of you who have been operating for a while and/or might have a similar setup... Where under the cowl would be the most useful place for an air temperature probe? Inside the plenum (on the back baffle)? Outside the plenum (near the top of the firewall)? Somewhere else?

In operation, do you frequently say, "It sure would be useful to know how hot/cold it is in location XX."??

Thanks for any advice or thoughts.

-Geoff
RV-8 almost done

I LOVE THAT IDEA. My plan is to make it movable. Some locations and temps I want to look at.

alternator (back) below Cyl #1
battery on Firewall
Center of engine case top (cooking spark coils of Lightspeed)
Oil cooler air inlet
Oil cooler air outlet

[flyeyes]

Originally Posted by gmcjetpilot

I LOVE THAT IDEA. My plan is to make it movable. Some locations and temps I want to look at.

alternator (back) below Cyl #1
battery on Firewall
Center of engine case top (cooking spark coils of Lightspeed)
Oil cooler air inlet
Oil cooler air outlet

Something I have done (quicker and cheaper) is to sprinkle some of these temperature sensitive stickers around under the cowl.

I found the back of my alternator was running much hotter than I realized, and the left side of my accessory case is 30-40 degrees cooler than the right (my oil cooler is on the right).

[gmcjetpilot]

Originally Posted by flyeyes

Something I have done (quicker and cheaper) is to sprinkle some of these temperature sensitive stickers around under the cowl.

I found the back of my alternator was running much hotter than I realized, and the left side of my accessory case is 30-40 degrees cooler than the right (my oil cooler is on the right).

Great Idea as well. I aw those. How well do they work? I see your link. Where did you buy them and what temp range did you use?Thanks

The tape of course is only a peak. I wounder how accurate they are? I see they are in 5F increments. If they are accurate with in +/- 5F, that would be close enough.

BTW what kind of temp are you getting on the alternator?

PS Suggest a heat shield off the back of the alternator. Radiant heat off the pipes gets the alternator real hot. That is why I suggest blast air as well.

[flyeyes]

Originally Posted by gmcjetpilot

Great Idea as well. I aw those. How well do they work? I see your link. Where did you buy them and what temp range did you use?Thanks

The tape of course is only a peak. I wounder how accurate they are? I see they are in 5F increments. If they are accurate with in +/- 5F, that would be close enough.

BTW what kind of temp are you getting on the alternator?

PS Suggest a heat shield off the back of the alternator. Radiant heat off the pipes gets the alternator real hot. That is why I suggest blast air as well.

I bought them from the sit at the link above. I think the 110-3 is about right for most accesssories, since anything under 180 degrees in the engine compartment is probably OK, and anything that is peaking over 200 degrees probably needs more cooling or shielding. You can get several in various ranges, depending on what your concern is.

They are probably a good idea on the radio stack as well.

I have 8 or 10 on various items, and check them every time I have the cowl off, or after a "hot" flight (e.g. long climb with high OAT). My firewall mounted battery nevery gets too hot (sticker on the forward face) and my fuel pump and left mag stay cool. The right "mag" (hall-effect sensor) wil touch 190 degrees, and the back of the alternator will touch 200.

I think they are very accurate, and they are widely used in industry for similar things.

[kentb]

It is fun to explore what the temp. is at different spots. Long term I plane to mount them around the firewall somewhere as a crude fire detector.

Kent

[N91CZ]

Originally Posted by flyeyes

Something I have done (quicker and cheaper) is to sprinkle some of these temperature sensitive stickers around under the cowl.

I found the back of my alternator was running much hotter than I realized, and the left side of my accessory case is 30-40 degrees cooler than the right (my oil cooler is on the right).

One thing to keep in mind when using these temperature labels is that most items under cowl don't see their highest temperatures until after engine shut down. The cylinders cool down and everything else heats up. The temperature rise after shut down for some components can be quite dramatic.