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Skyview data log RPM during mag check?

Pmerems

Pmerems

Well Known Member
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I was looking through some of my old logged data from my flights and I noticed the system wasn't recording the change in RPM during run up. The data log captures data 4 times a second (.25 sec). The Skyview data logger has a RPM L and RPM R column but the data in both are the same. The data logs from my old D180 only had a single RPM column.

The Skyview displays L and R RPM drop fine but doesn't capture it the data log.

Anybody else notice this? Is mine wired wrong? Is the logger not collecting the respective RPMs? Am I having a senior moment?

Stay tuned for the responses from the forum. Same Bat time, Same Bat channel! (references the old Batman TV series for those young builders out there).
 
Without knowing how your skyview is wired it's hard to tell what's going on. Does each ignition have a pickup or how is it wired.

Bob burns n82rb rv-4
 
Wired per Dynon instructions.

The system is wired per Dynon instructions off the starter switch. That is how the RPMs are sensed. Not off a electronic tach sensor on the assessory case. Since RPM is displayed with either L or R mag on or off during mag check I believe it is wired correctly.
 
That's the way it works. It displays the maximum rpm. The l and r indications are misleading.
 
What type of ignitions do you have?

The data in the two columns should be the same but both should drop equally as the engine slows during the mag check.
 
N941WR said:
What type of ignitions do you have?

The data in the two columns should be the same but both should drop equally as the engine slows during the mag check.
Click to expand...

I see the mag drop on my data logs (looking at them via Savvy Analysis). I believe the RPM comes from *either* the L or the R mag, but not both (which one is primary, I don't know...have to leave that to Dynon to chime in).

Bottom line...works fine for me, wired as per the installation manual.

Perhaps you could post a screen shot of what you're seeing that makes you think it's not capturing RPM drop?
 
What I thought I would see

I would have expected to see a "zero" in the RPM column opposite the mag being checked and an rpm drop accordingly. But maybe the L R rpm columns are for a twin engine install someday? Dynon is thinking ahead?
 
Pmerems said:
I would have expected to see a "zero" in the RPM column opposite the mag being checked and an rpm drop accordingly. But maybe the L R rpm columns are for a twin engine install someday? Dynon is thinking ahead?
Click to expand...

I'm not sure but I think they may be wired together within the Dynon as mine reports both, even when one of my P-mags is powered off.

The reason I asked about which ignition you have is the P-mags, if installed per the instructions, will put out a tach signal when the P lead is grounded. I don't know if standard mags will do this or not.
 
From the install manual

SkyView will display RPM from either the RPM Input Left or the RPM Input Right, whichever is noticed by the SV-EMS-220 first. If the first RPM signal is lost (such as when one ignition source fails, or during a routine mag check), then SkyView will display RPM from the remaining RPM signal. If your engine only provides one RPM signal, connect it to one of the two RPM Input Left pins.

So I am guessing the columns will be the same but there should be a drop shown on only one mag.

Bob burns

Rv-4 n82rb
 
n82rb said:
From the install manual

SkyView will display RPM from either the RPM Input Left or the RPM Input Right, whichever is noticed by the SV-EMS-220 first. If the first RPM signal is lost (such as when one ignition source fails, or during a routine mag check), then SkyView will display RPM from the remaining RPM signal. If your engine only provides one RPM signal, connect it to one of the two RPM Input Left pins.

So I am guessing the columns will be the same but there should be a drop shown on only one mag.

Bob burns

Rv-4 n82rb
Click to expand...

No, there's a drop shown when *either* mag is turned off (and the engine RPM drops). It's measuring your actual engine RPMs (albeit via a different method)...whatever the cause of the RPM drop, SV will see it (assuming your actually get an RPM drop on each part of the mag check).

ETA: I just looked at a recent log file, and during the mag check, the two columns show identical numbers, both dropping about 100 RPM during each portion of the mag check (L off, then R off).

Granted it may be taking the *data* from a single input line, but the RPM L and RPM R columns both accurately display the engine RPM during all phases of flight, including run-up (prop cycle, mag checks).
 
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That's what I was trying to say I just didn't say it well. You should see both numbers the same but when you check mags they should drop a bit. Which it appears you are seeing.


Bob burns
N82rb rv-4
 
Savvy Analysis Skyview data files

Just noticed that my most recent upload to Savvy Analysis (April vs. Dec) now includes a lot more data elements than had previously been available in the SA website charts. While the Skyview datafile for some time now included all kinds of things like autopilot settings, GPS settings, transponder settings etc... many of these were not available to be charted on the Savvy Analysis website. Tonight there is a much longer list of data elements that can be charted and compared to each other. Nice surprise.
 
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