Mailing List flyrotary@lancaironline.net Message #64061
From: Todd Bartrim bartrim@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Re. Rescaling the EM2 to metric
Date: Sat, 23 Jun 2018 14:59:03 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Below is my EM2 calibration data table. I hope it comes through to the list OK, otherwise I'll post a link.
The only Dynon I have is the D10A, which is just flight instruments, so other than sharing a pitot probe there is nothing common. The Dynon has it's own OAT sensor which is connected through the EDC magnetometer (electronic compass)

EM2 Calibration Data
Ch. #FunctionScale FactorZero OffsetSensor OffsetLow LimitHi Limitsensor typelocation
0H2O temp3.15220447100VDO 323 095H2O out of engine, before cooler
1Aux air 23.6069LM34DZbehind right radiator air
2aux LT 11.82520490VDO ? 323 057Oil Sump, before cooler
3RT fuel0.572511756SW F-385CRight Outboard tank
4oil temp3.2192044590VDO 323 095Oil into engine, after cooler
5LT fuel0.784511828SW F-385BLeft Outboard tank
6aux air 3
7aux LT 23.11420446VDO 323 095H2O into engine, after cooler
8oil press9.4360552595VDO 360 086DOil into engine, after cooler & filter
9H2O press32.21108821VDO 360 043Coolant swirl bottle
10aux air 18.1050176LM34DZbehind left radiator air
11OAT8.6660439LM34DZunder right wing root
12fuel press13.7099VDO 360 086fuel rail loop
13mixture5.11900
14air speed10.00804645200
15altitude3.598-507542
16CHT 10.4540J type TCfuel filter/water seperator
17CHT 20.4540J type TCMOCAL oil inlet
18CHT 30.4540J type TCMOCAL H2O inlet
19CHT 40.4540J type TCvarious, currently cowl air out
20EGT 11.0460950K type TCRotor #1 exhaust
21EGT 21.0460950K type TCRotor #2 exhaust
22EGT 31.0460950K type TCTIT, turbo inlet
23EGT 41.0460500K type TCexhaust pipe 30" downstream of turbo
24MAP13.63930.029371
25voltage6.277100130155

The temp sensor that is in the oil sump (aux LT 1,channel 2) has far different cal data as the other VDO temp sensors. I'm not sure where I got it from and it has no markings on it, but it's ohmic range matches the published data for a VDO 323 057 (max 150C), so I'm assuming that is what it is, but take that one with a measure of skepticism. It calibrated fine so I'm using it for now, but my next order from ACS will include a new VDO 323 095, to match the others.

Todd

Todd Bartrim

On Sat, Jun 23, 2018 at 4:42 AM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
Hi there Todd
I’d be very interested in the settings though I have an EM3 and I’m not sure of the difference between models 2 and 3.
Do you have all seperate senders for the Em2 and Dynon?

Steve Izett




> On 23 Jun 2018, at 5:33 pm, Todd Bartrim bartrim@gmail.com <flyrotary@lancaironline.net> wrote:
>
> Ok, as I can never leave well enough alone, I took another look at this.
>   First as soon as I took a moment I realized that the J&K thermocouple would be real easy to calibrate and convert to metric.
>   I used a Fluke temperature calibrator with a millivolt output to simulate the TC"s. Worked like a charm.
>   I tried to use the same calibrator to simulate the variable resistance of the VDO probes, but they are thermistors which are very non-linear, so even with the tables it was a challenge.
>   So I brought home a Fluke 9009 dual dry block temperature calibrator. Good for -20°C up to 350°C at the same time (separate temp wells).
>   That made it easy, fast and very accurate.
>   However, the one that I'm worried about is the OAT as this one is also used to calculate TAS, HP, and "other readings".
> Now I believe I can correct the TAS by calibrating the scale factor on the airspeed in flight against the TAS on my Dynon.
> HP is an arbitrary number anyways based on what I think my max HP should be. I think I can tweak that factor as well to get it back to what I think it should be. And if I ever meet a Dyno I'll be sure to try to calibrate it properly.
>   But the manual also mentions "other readings" without details.
> So I've put in an email to Tracy.
> If it turns out to be important, I can always put this one back and just ignore the OAT. (Its also on the Dynon)
>   So if any of you metric blokes down under would like to do this, I can post all the parameters which you can input to your own EM2 and it will get you close.
>   For very accurate calibration you would have to tweak them a bit using a temperature calibrator.
>
> Todd
>
> On Fri, Jun 8, 2018, 00:46 Todd Bartrim bartrim@gmail.com, <flyrotary@lancaironline.net> wrote:
> Hi Andrew;
>  I haven't spent much further time on the metric conversion. I think it wouldn't be as simple as I hoped. It was fairly straight forward to convert the fuel level to litres and most of the temp measurements should be almost as easy, but the K & J thermocouples have different raw data, that I don't believe would be easy to convert. And then some of the calculated parameters will likely be adversely affected as well. Probably not impossible, but first, I just don't have the time and second, I would probably have to be bugging Tracy a lot for info and he's busy being retired in the mountains of Colorado where he seems to be online only occasionally.
>    I have however longed for a data-logger which the early EM2 didn't have (I have #003). With the increasing popularity of hobby microcontrollers I can get a Ardurino microcontrollers for $35 and a datalogger for it for $6, so I just asked Tracy about the possibility of harvesting data from the EM2.
>   However for a few other reasons, I'm considering that next time someone on the list is selling an EM3 from an abandoned project, I might buy it for an upgrade. I think there was one recently but it was bought up right away.
>
> Todd Bartrim
>
> On Thu, Jun 7, 2018 at 7:58 PM, Andrew Martin andrew@martinag.com.au <flyrotary@lancaironline.net> wrote:
> Todd, did you ever get the EM2 recalibrated to metric? I never attemped this as doing so usually gives me quite a few hours work to get back to a working system. I used Tracy’s factory calibration in the EM2 as the base to calibrate my efis, which is in metric. It is a minor inconvienience to do the mental arithmetric when comparing instruments, but would be interesting to know if you succeeded.
> --
> Regards Andrew Martin Martin Ag
>


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