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New Rotax SB-912-066UL Don't Worry!

Bill_H

Bill_H

Well Known Member
A new Rotax SB has been issued as of 12-10-14.

http://legacy.rotaxowner.com/si_tb_info/serviceb/sb-912-066ul.pdf

For us RV12s, for 912ULS engines above a certain serial number, the cylinder head is different. (Or if you have replaced a cylinder head, you might have the new type.)

The new head measures the coolant temperature much more directly than the old head. The SB wants you to note that in your records and ensure your instruments show a lower redline coolant temp of 120 deg C IF YOU HAVE the new style head.
 
I don't remember seeing a coolant temperature indicator on the Skyview. Is it the same as cylinder head temperature?
 
Read the SB. The original head design was more a measurement of the head temperature. The redesign more closely measures the actual temperature of the coolant, rather than the head, hence the desired relabeling and different limit.
 
Bill_H said:
Read the SB. The original head design was more a measurement of the head temperature. The redesign more closely measures the actual temperature of the coolant, rather than the head, hence the desired relabeling and different limit.
Click to expand...

Good to know thanks Bill, you saved me 15 minutes of reading :)!
 
Bill_H said:
Read the SB. The original head design was more a measurement of the head temperature. The redesign more closely measures the actual temperature of the coolant, rather than the head, hence the desired relabeling and different limit.
Click to expand...
Sounds like if your engine is affected then you have to change the way it reads the same information.

So, if you identify your own aircraft engine as being affected are you then required by the SB to re-label the CHT on the Dynon screen and change the temp limit?

If so, how is this done?
 
They are a little late with this

I saw the new cylinders on display at the Rotax booth back in July at Oshkosh and asked about the new location of the sensor on the top of the engine instead of on the bottom (actually easier to access BTW). Wonder why it has taken this long to issue a notice?
 
The Skyview installation and operators manuals tell how to add, delete, display, and modify sensors. it is very easy to change indicator and alarm ranges. And to some extent, text descriptions.

Things like this and similar things going forward are what will make it impossible for Van's to have a single "config file" to load into RV12s that will work correctly with all models and options.
 
I had a reply from Vans. They said they're still looking at it but expect to have a settings download posted at some time which will be able to set the RV12 to the Rotax requirement in the SB.

They've done this before and when I uploaded the Dynon software from the Vans site it already had the settings done so I'll refrain from fiddling with it for now.
 
During the 11.1 update, I reselected the Rotax 912 and I just checked and my CHT redlines are set to 248 F in the EMS settings file, so as near as I can tell, all I need to do is a logbook entry saying complied with, someone correct me if I am wrong. (E-LSA)
 
OK, so I'm in the affected serial number range. I'm gonna alter my Dynon to read "L & R coolant temperature", and set the red line at 248 degrees F (which is 120 degrees C), and make a log entry. Right? Any suggestions on where to set the yellow arc? I'm thinkin' 238-248 degrees F.

Thanks,
Jim
#120621
N448JR
flown 200 hours since 9/13
 
I had done a thorough check of the Rotax manuals and came up with these values for the OLD CHT RANGES in Deg F, not these new style sensor placement ones.

CHT
max_display=270
min_display=100
0-120 Yellow
120-230 Green
230-245 Yellow
245-270 Red
 
OK I checked with Dynon, and, as usual, they got back to me almost immediately. Those of us with Dynon Skyview can use the instructions in Chapter 7 of the SkyView Installation Guide for Sensor Input Mapping. There we can change the text of an engine indication (in this case, change L/R CHT to L/R Coolant temp.). Then, same chapter, refer to Sensor Settings to change Maximum (red line) to 248 degrees F.

I like the idea of a caution (yellow) range just below the red line, but neither the Service Bulletin nor the Rotax Operators Manual give such a reference.

Moreover, the RV-12 Pilots Operating Handbook, Section 3 Operating Limitations, needs to be amended to show this change, but that revision must come from the aircraft manufacturer.

I appealed to Vans on this issue, got the usual curt response, no help.

Thanks,
Jim
 
Bill_H said:
This SB has had a slight revision involving showing more info about the newer heads and updating various sections in the ROTAX manuals about several different issues. It is here. http://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-912-020-r8.pdf
The main thrust of the SB was not affected.

I download the latest versions of Rotax and Dynon manuals as they change and keep them on my IPad.
Click to expand...

For these new cylinder heads, as the coolant temperature is monitored now and as the coolant is constantly moving through the cooling circuit of the Rotax 912, one may assume that it averages across the four cylinder heads, I wonder why one would continue to monitor the temperature of the coolant of 2 out of 4 cylinders. This would leave the sensor of one cylinder head available to measure some other devices' temperature like the "Voltage regulator" with minimal work involved.
 
This would leave the sensor . . . available to measure some other devices' temperature like the "Voltage regulator" with minimal work involved.
Click to expand...
The Dynon D-180 has a spare thermocouple input, EMS pins 27 & 28. The Skyview most likely does too. Bill_H would know.
 
You don't need to worry over CHT or coolant temps because Rotax has no minimum. This has been just recently discussed and posted on the Rotax forum.
 
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