From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Re. Rescaling the EM2 to metric
Date: Sat, 23 Jun 2018 19:42:36 +0800
References: <list-11292871@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-11292871@logan.com>
Message-Id: <8C492A6A-E6A4-428B-A7B2-3598831F00AB@gmail.com>

Hi there Todd
I=E2=80=99d be very interested in the settings though I have an EM3 and =
I=E2=80=99m 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:
>=20
> 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.=20
>   I used a Fluke temperature calibrator with a millivolt output to =
simulate the TC"s. Worked like a charm.=20
>   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=C2=B0C up to 350=C2=B0C at the same time =
(separate temp wells).
>   That made it easy, fast and very accurate.=20
>   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.=20
>   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.=20
>=20
> Todd
>=20
> 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.
>=20
> Todd Bartrim
>=20
> 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=E2=80=99s 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.
> --=20
> Regards Andrew Martin Martin Ag
>=20