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JR DMSS Temp Sensor

ryan_m

100cc
Ok guys what would be a normal temp or high temp. I would like to set my alarm for high temp. I. Thinking 240.? New ball game for me.

I think that depends on a variety of things... primarily exactly where you have your sensor. I've got another thread I started on here asking about temps and what was normal or too high. On the plane I have temp telemetry on I was/am seeing fairly high temps I used to think. Prior to getting telemety the motor shut down once in the air from getting too hot. It was lean, and I didn't have it baffled. The plane is a 3dhs 91" Yak 55, and the motor is an EME 70 twin. I richened the motor, baffled it, and installed telemetry. I installed my temp sensor on the back/top of one of the fins. Basically the hottest part of the motor. After baffling and richening I was seeing temps in the 285-340 range. But the motor never faded on long uplines and has never again quit. It seems quite content to run there. I still worry a bit that it's too high, but there isn't much else I can do to cool it any more. I've modified the baffling to let in more air, and opened the cooling vents more to help get more airflow. Dropped the temp slightly, it usually doesn't get over 325 now, even on 90 degree ambient temperature days.

Opinions on what was normal temps seem to vary quite a lot. Several guys told me my temps were fine given where the sensor was, others said it was too hot, others said that as long as the motor doesn't fade out on a long upline then don't worry about it. So I mostly don't worry, and set my alarms for 340. If it goes off, I stop whatever I'm doing to make it get hot (spins are the worst) fly straight and level at 1/2 throttle or so, and it cools down quickly to 310 or so.
If I had mounted my sensor on the front of the cylinder I think I would probably only be seeing temps in the 250 range.
 
At the upper most find at the back of the head
 

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Flyncaps

New to GSN!
Actually I have been looking for something like that to compare to.
Me and another guy have been using these for a couple of years now to make sure we get the baffling
right in our planes. I was very surprised to see the real temps these things normally run at. I have
compared them to many different sensors. These are the most consistent. I have ran it along with a setup
identical to yours, you're gonna be surprised!, I was!!! I know someone that has the knowledge what we should
watch for as far as peak temps, His reply was " Brief peaks to 400F are OK, under that you should not have a problem"
Here is mine.
 

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mikeh

70cc twin V2
I wish I would have had the sensor on before I baffled the motor. I put the sensor on the back side of the head towards the spark plug. I was seeing Temps at 185-205. Motor is no longer sagging. My air inlet to exit is 1:3. The motor is still breaking in so taking it easy. No 3d flying, just straight lines with throttle going full throttle occasionally.
 

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