Carb temp alarm settings.

Let me pick some of the collective brains here. With the Dynon EMS 120, I have a carb temp sensor (see prior post). With the setup, you have the ability to set a color coded bar up just like your EGT and CHT, etc. I know, humidity plays a role in carb icing, I just want to have something setup and also don't want the dang alarm going off constantly.

What would be good settings for upper green, upper yellow.

how about measured carb temp data?

I don't have any temp settings, but I'm interested in carb heat (especially after getting iced up in a 150 this summer) and I saw a recent post about RVs not having "effective" carb heat....

Does anybody have measured data showing OAT and carb temp with heat on & off? It would be interesting to see, while I await my wings (in Vans "crating" today).

Thanks!

Some Commercial Gauges

BlackRV7 said:

Let me pick some of the collective brains here. With the Dynon EMS 120, I have a carb temp sensor (see prior post). With the setup, you have the ability to set a color coded bar up just like your EGT and CHT, etc. I know, humidity plays a role in carb icing, I just want to have something setup and also don't want the dang alarm going off constantly.

What would be good settings for upper green, upper yellow.

Click to expand...

Dana.... Westach uses -10C to +10C as a Caution (yellow) zone

http://www.aircraftspruce.com/catalog/inpages/carburetorairtemp.php

This other one seems to use a caution area that is 5C lower, of -15C to +5C

http://www.aircraftspruce.com/catalog/inpages/carbtempkit.php

Hope this helps.... Since it's a caution, can a flashing color be used instead of an audible signal?

IowaRV9Dreamer said:

I don't have any temp settings, but I'm interested in carb heat (especially after getting iced up in a 150 this summer) and I saw a recent post about RVs not having "effective" carb heat....

Does anybody have measured data showing OAT and carb temp with heat on & off? It would be interesting to see, while I await my wings (in Vans "crating" today).

Thanks!

Click to expand...

Just did a carb temp test this afternoon on my O-320 powered 9A. OAT was 64 and the carb was running in the high 50's during taxi testing. Pulled carb heat after a few minutes and watched it climb to 125 on my AF2500 engine monitor. I feel pretty comfortable with that. I was doing high speed tests, enough to lift the nose wheel. First time for that, and it felt goooood!

Bob Kelly

What kind of temps are you seeing in flight

videobobk said:

OAT was 64 and the carb was running in the high 50's during taxi testing. Pulled carb heat after a few minutes and watched it climb to 125 on my AF2500 engine monitor. I feel pretty comfortable with that. I was doing high speed tests, enough to lift the nose wheel. First time for that, and it felt goooood! Bob Kelly

Click to expand...

Congrats, WHAT KIND OF CARB HEAT SET UP DO YOU HAVE? Wow that is excellent 60F rise at idle or taxi. OK that is cool, I mean HOT. Let us know what you have set up, exhaust, carb heat muff, etc....

The range I'm using on the EIS4000 is 14F to 50F (-10C to 10C)

I also purchased the ICE MAN, used on ebay got a heck of a deal on it. Uses an optical probe to detect actual ice. May be too sensitive to be practical from what I have read about them, but plan on giving it a whirl. Can't have both CAT and the ICE MAN probe. I'll let you know.

My feeing is just situatuinal awarness, humidity, temp and any drop in RPM or MAP should keep you out of trouble, but the CAT is nice to have.

Any one got temps in flight? A few guys seem to always have high temps with or without carb heat at cruise power.

real data, yay!

videobobk said:

Just did a carb temp test this afternoon on my O-320 powered 9A. OAT was 64 and the carb was running in the high 50's during taxi testing. Pulled carb heat after a few minutes and watched it climb to 125 on my AF2500 engine monitor. I feel pretty comfortable with that. I was doing high speed tests, enough to lift the nose wheel. First time for that, and it felt goooood!

Bob Kelly

Click to expand...

Bob - thanks so much for the real data. I've "heard" so often than Vans carb heat is no good, but 125F seems pretty good! I am thinking about the new Vetterman exhaust with mufflers - I bet they throw off a lot of heat. What exhaust do you have, and how is your carb heat done (1 muff, 2 in series?, vans air box, ??)

Please remember this thread and post a picture of your carb heat setup and also some airborne temperature data when you've flown. Thanks again!

BTW - I'm way jealous! I can't wait to have a 9A!

Followup

My setup is pretty straightforward; Van's airbox with the top scat tubing reaching up to about 1-2" below the exhaust. The cowl is pretty well sealed around the carb air intake and elsewhere which I would think would help. I would think some of the heat rise had to come via radiant heat on the carb, but I thought 125 was way good. I also noticed that the trapdoor does fit very tight inside the airbox, keeping out most of the outside air. I bought the engine off a hurricane charlie'd RV-6A. It has 885 hours TTSN and apparently the guy who built it did an excellent job with baffles, etc. My CHT's are very close, although I have only taxied.

Side note: It was amazing how easy the nose came up today and how easy it was to hold it up as I rolled out. This thing wants to fly almost as much as I do!

Bob

Carb Alarm

My Electronics Intl carb temperature gauge has an amber light that comes on at 39 deg. F, + 4 C. Temperature is measured in carb throat.

I find carb temperature rise is much greater at low power settings such as final approach where I might see 40 - 50 degree F temp rise however in cruise flight I only see 28 deg F rise over ambient temp.

My 0-320 system has a much larger heat muff than standard, it wraps around both crossover pipes, also a larger diameter scat tube (2 1/2").

I think we loose a lot of heat as the air expands on entering the airbox and also going through the air filter.

-10 +10

Looks like -10C +10C is the nature of the beast.

Thanks gang.