Emag Temperature Monitoring

[stewarth]

Hi,
Is it possible to display the Emag temperature on our D180. We have an RV7 that runs on the hot side of things and we know that the Emag is getting very hot, despite all.
Rather then the expense of a stand alone display it would be
much more convenient on the Dynon. Regards. Stewart.

 

[DBRV10]

First thing to do is solve your "runs on the hot side" matters.

For a start, and I openly declare, I am not a fan of any of the currently available EI systems, I can go on for ages about why but that is not the topic here now.

So first of all, make sure the timing is on the most conservative setting and even then retard it a few degrees. Make sure your magneto is timed accurately too.

Do you have a CS prop? if so do you see fuel flow of 18GPH (assuming a 180HP at sea level?)

once you have a known conforming engine setup, then start working on baffles etc. Most folk with a plenum seem to think they will have better cooling. They do not. They may have less cooling drag, but often higher CHT's.

This is only the tip of the iceberg.

As for other GP inputs there are a couple, have a read of the manual at the end of section 3

You may configure the FlightDEK-D180 to monitor one J or K type thermocouple. Dynon Avionics does not supply a specific general purpose thermocouple probe for this purpose. However, our standard EGT and CHT probes will work, as will any other J or K type thermocouple.
Dynon Avionics sells both J and K type thermocouple wire which may be used to connect the desired thermocouple to the FlightDEK-D180. Ensure you order the correct wire type for the thermocouple you intend to use. Crimp a female D-sub pin on the end of each wire, and plug them into the D37 connector. Polarity is important, so ensure that you are routing the positive side (yellow for K-type; white for J-type) of the thermocouple to pin 27 on the 37-pin harness, and the negative side to pin 28

 

[mmarien]

The E-mags and P-Mags output serial data which can be read with the EICAD program (available on the E-Mag site) and displays a temperature. I don't believe it's that accurate but it's a measure to gauge. I believe it remembers the highest temp so you can read it on the ground after a flight. I made permanent serial connects to both my P-Mags to monitor them in flight but I don't do that a lot. It would be nice to be able to read the serial data stream and display it on Skyview but I don't think that will happen. Besides I maxed out the SV serial ports with other good stuff.

The problem with using a thermocouple as David suggests is that you can't put in inside the P-Mag. Outside there are too many influences from other heat sources to be accurate. I put a couple of scat tubes to get some cooling on my P-Mags. It's not an option - page 17 of the manual. I think that's recommended for both EI and regular mags as I seen it on regulars mags also.

David also has a good hint with his 18GPH rhetoric. The best way I found to manage the heat is get the fuel burn down. 18GPH is twice the BTU's of 9GPH. I'm a big believer in Mike Busch's attitude. I now fly WOT and just crank the RPM and mixture down. It's sucking a whole lot of air and a rationed bit of fuel and still going fast.

 

[DBRV10]

If the EMAG data is available internally, even not accurately, it will be far better than a thermocouple stuck on the case as you have said, but the OP asked about displaying it in his D180, so I guess there is not much of a compromise.

18GPH is twice the BTU's of 9GPH. I'm a big believer in Mike Busch's attitude. I now fly WOT and just crank the RPM and mixture down. It's sucking a whole lot of air and a rationed bit of fuel and still going fast.

Is this in the cruise or in the climb at takeoff? Using a standard compression engine that is about 134HP, so referenced to peak EGT where are you?

And twice the available BTU's but when full rich they are not exactly converted well and are there for combustion event retarding. Keeping Theta PP where it belongs

 

[mmarien]

Is this in the cruise or in the climb at takeoff? Using a standard compression engine that is about 134HP, so referenced to peak EGT where are you?

A bit off topic, but thanks for asking David.

Once the throttle is full forward for takeoff it just stays there. All my EGT probes are fried so I don't pay much attention to them. I'll replace them at annual. The mixture is managed by electronic fuel injection. At cruise RPM the air fuel ratio (AFR) is about 15 which is near peak EGT or stoichiometric burn which is why my EGT probes are fried. They were reading close to 1600F. All other RPM's are tuned to an AFR of 13 which is rich of stoichiometric burn but near the top of the power curve. So during climb, high load, high RPM the AFR is a nice safe rich mixture which effectively avoids detonation but surprisingly results in maximum power. When I turn the RPM down for cruise (still WOT) it's near peak EGT which is on the lean side but the engine is under a light load and detonation is less likely. If you have a CS prop there is not a lot of reason to starve the engine breathing by throttling it. I'd do away with the throttle altogether but it's more difficult to line up and hold using just the ignition kill switches.

See here for the logic of AFR: en.wikipedia.org/wiki/Air–fuel_ratio

And twice the available BTU's but when full rich they are not exactly converted well and are there for combustion event retarding. Keeping Theta PP where it belongs

True. Perfect burn is at stoichiometric which gives the hottest flame or peak EGT. When you're using a richer mixture you're not producing maximum BTU's from the fuel, just stifling detonation but producing more power. Strange but true.