expected temps at spark plug?

[trillian]

On my Helix (stock Zenoah 260RC) there is a Spektrum TM1000 with a temp sensor around the lower bit of the spark plug.

What sort of range would you expect at the plug?

At first I was only seeing it reach mid to high 60s celcius. I thought the sensor wire might not be snug enough so I tried to pull it a bit tighter and on my last flights I was seeing it reach 75C (approx 165F).

I also suspected the engine had been a bit rich the previous time out so I leaned the high needle just a hair which made a noticeable improvement in power.

[rcnut]

It really depends on the type of day. All 3 of mine are in the mid 200's, like 215-260.

Average...around 240...

My temp sensor ring is mounted under the plug.

[trillian]

So do you have one of the specially made sensors that goes on like a washer between the plug and the head?

Originally Posted by rcnut

It really depends on the type of day. All 3 of mine are in the mid 200's, like 215-260.

Average...around 240...

My temp sensor ring is mounted under the plug.

[Doug Darby]

I ran the Trail Tech gauge for several years that used the Cylinder Head Temp sensor that replaced the plug washer. I routinely saw temps of 350°F to as much as 410°F running my TRMVX270TT with a QuickDraw Pipe in the Summer in the South.... I quit running it because the sensors did not have a very good mtbf...

[rcnut]

I'm using the Trail Tech gauge on all 3 gassers. My highest temps during the hottest time of the year was 307. I richened the carb some and ran at 270-285.

2 of the 3 motors are the TRMVX275TT, and the other is the Hanson 300 3D Max. All 3 use the RJX muffler.

[Doug Darby]

As many will tell you on this site, blindly following any temp indicator on an engine is asking for trouble. If you carefully read the plug and the other signs the heli gives you for a good tune, then the temp gauge will provide a nice indicator of changing conditions once you use other indicators to build a baseline for each engine. And yes you can find that each engine can require slightly different needle settings for the same performance.

[trillian]

Originally Posted by Doug Darby

As many will tell you on this site, blindly following any temp indicator on an engine is asking for trouble. If you carefully read the plug and the other signs the heli gives you for a good tune, then the temp gauge will provide a nice indicator of changing conditions once you use other indicators to build a baseline for each engine. And yes you can find that each engine can require slightly different needle settings for the same performance.

Yeah I was just curious if anyone else was using the same kind of sensor around the plug to see if it seems in the ballpark or obviously out (such as if the sensor is making poor contact with the plug or something).

I can generally tell from the sound and a few other things, how the engine is doing, and now and then checking the plug colour.

[rcnut]

I use the temp gauge for reference only. It gives me an idea of where the motor is temp wise from day to day.