Coolant Temp

[N40CG]

My engine (912UL2) came with the threaded port for a coolant temp probe plugged. I bought a "MGL Precision Water/Oil Temp Probe" from Aircraft Spruce (11-05570) & connected it to pin 4 & gnd on the DB37. I can't find an option in configuration that will correctly handle what the probe is saying. HELP!!

 

[dynonsupport]

Unfortunately we don't support that MGL sensor. Most people don't monitor the coolant temperature directly on the 912, as the heads are liquid cooled and hence the CHT is sort of a coolant temp sensor itself.

 

[N40CG]

:Understood, but the capability & wiring are in place so I may as well use it. Does Dynon offer a probe with a 10mm x 1.5 thread that'll work?

 

[dynonsupport]

Is this on a SkyView or a D100/D10 series product?

 

[N40CG]

Skyview D1000.

 

[dynonsupport]

Are you sure you're looking at a coolant temperature port? I'm not familiar with the exact mechanicals, but I was under the impression that there was no dedicated place for coolant temperature readings, and that people that choose to do so have to tap into a coolant line somewhere. Further, Rotax themselves would rather you use the preinstalled CHTs, which basically measure coolant because of the liquid cooled heads. See http://www.rotaxservice.com/rotax_tips/engine_instruments.htm for some of the guidance here from one of Rotax's service centers.

 

[dynonsupport]

Actually, if you mean you're missing one of the normally pre-installed CHT/coolant temp sensors (one per side), you can get them from Rotax dealers like Lockwood Aviation Supply: http://www.lockwood-aviation.com/

 

[N40CG]

Yes, I know coolant radiator connections when I see one. You may not be familiar with this application -- it is a Pipistrel Sinus motorglider which I built from a kit. There is a threaded port with a 10mm x 1.5 thread in the riser pipe from the engine to the radiator. The riser pipe is an engine modification that Pipistrel adds to the Rotax engine to accommodate their configuration. It is electrically insulated from the engine case by the hoses from the riser pipe tee to the coolant fittings on each cylinder so a 2-conductor (isolated) probe, which the MGL probe is, is necessary. The engine came with probes for a European Brauniger pfd/ems instrument which, like the MGL which is a LM335 diode, you don't support. I've bought 2 of the Rotax oil/cht temp probes (yes, there's one each in cylinders 2 & 3 plus one in the oil temp port) @ $186 apiece from Lockwood and am quite familiar with them. I repeat my previous question -- Does Dynon sell a 2-conductor probe with the metric thread that will give me coolant temp? Granted it isn't absolutely necessary with the CHT reads -- the D1000 is also GROSS overkill in this airplane, but it is my plane @ that's the way I want it. If so, please tell me how to order one. Or can the LM335 be added to the probe definition file? I've looked at that procedure briefly but not enough to really understand everything that goes in there.

 

[dynonsupport]

We only sell two fluid temp senders, both imperial thread, both single wire:

Oil/Coolant Temp, 5/8-18 UNF
Oil/Coolant Temp, 1/8-27 NPT

We of course also support the Rotax CHT/Oil temp sender.

They don't need to be two wire. You can always hook a wire to the body of the sensor and run that to the EMS module's ground. So if you can get an adapter from your thread to any of the 3 listed sensors, that will work.

It is possible to add the LM355 to the sensor file if you have the technical know-how to get voltage vs. temp curves and do a little math.

 

[N40CG]

OK, Thanks. The LM335 curves are available on-line, I'll play with that. I don't really want to put out another $186 for a Rotax sensor.
Cliff

 

[dynonsupport]

There is an $18 VDO equivalent to the Rotax CHT, fyi. The one difference is that the threads are more coarse than the original, so it's not a drop in replacement for the stock CHTs. Lockwood Aviation carries them.