Tach time

[kortopates]

3 hours ago, Pinecone said:

OK, it LOOKS like a Hobbs meter.

My POH does not mention it, that I can find.  And it not shown on the schematic.

Where would I find that it is wired to the tach?

Yes, these details aren't in the POH but service manual. See this excerpt below from the M20K Service Manual.  The complete electrical schematic by serial number is also included in the back of the the SM, but that is a huge drawing and you'd have to locate that portion of the schematic and trace between the Tach and Hour meter. But the included text explains it clearly.

[Pinecone]

1 minute ago, kortopates said:

Yes, these details aren't in the POH but service manual. See this excerpt below from the M20K Service Manual.  The complete electrical schematic by serial number is also included in the back of the the SM, but that is a huge drawing and you'd have to locate that portion of the schematic and trace between the Tach and Hour meter. But the included text explains it clearly.

 

Thanks.  But my serial number is 25-1057, so it runs off the alternator Aux terminal.  But it does not match run time (timed by GTN650 time), so maybe it is getting RPM info from the alternator.

 

[kortopates]

54 minutes ago, Pinecone said:

 

Thanks.  But my serial number is 25-1057, so it runs off the alternator Aux terminal.  But it does not match run time (timed by GTN650 time), so maybe it is getting RPM info from the alternator.

 

?? Please re-read the highlighted text - all serial numbers later than 447, which includes all 252's including yours with SN 1057, "operate from the electric tachometer". Not the alternator. Only the early 231's, sn's 001-446, operated off the alternator and measured time when the alternator was producing current.  

[Pinecone]

2 hours ago, kortopates said:

?? Please re-read the highlighted text - all serial numbers later than 447, which includes all 252's including yours with SN 1057, "operate from the electric tachometer". Not the alternator. Only the early 231's, sn's 001-446, operated off the alternator and measured time when the alternator was producing current.  

DUH. 

Multitasking poorly.  Trying to work and read MS at the same time.  I need to pay more attention to MS.

Ok.  So if I were to put in a JPI 900/930 or Garmin EIS, I would just set it to record tach time with a 2550 RPM base RPM?

[kortopates]

48 minutes ago, Pinecone said:

DUH. 

Multitasking poorly.  Trying to work and read MS at the same time.  I need to pay more attention to MS.

Ok.  So if I were to put in a JPI 900/930 or Garmin EIS, I would just set it to record tach time with a 2550 RPM base RPM?

Yes, you can do exactly that as many Mooney owners have already done. Or you can also simply replace the Mooney tachometer with the EI R-1 digital Tachometer, it fits in the same footprint sized hole as the Mooney tach works off the ignition switch,  I have both a EDM-900 and R1 for redundancy and had EI program my R-1 with the hours I had when I made the change. 

[carusoam]

Work is over rated…

Consider retiring to have more MS time….

 

-a-

[Pinecone]

4 hours ago, carusoam said:

Work is over rated…

Consider retiring to have more MS time….

 

-a-

 

That is the plan.

Especially since I just ran the figures, and I will get a pay raise when I retire.

 

[MikeOH]

15 hours ago, Pinecone said:

 

That is the plan.

Especially since I just ran the figures, and I will get a pay raise when I retire.

 

Sign me up for that plan!!

[ArtVandelay]

The new firmware displays the tach time on the main screen.

What about hobbs time with new firmware?

[Pinecone]

The JPIs record Total time from power on to power off.  Also they do Tach Time based on revolutions based on a certain RPM being equal to clock time.  That RPM is setable.

Based on comments here, it seems that the Mooney uses 2550 as the base RPM.

Although it seems that the common RPMs are 1800, 2050, 2300, 2400, 2566, and 3000.

[Marauder]

The JPIs record Total time from power on to power off.  Also they do Tach Time based on revolutions based on a certain RPM being equal to clock time.  That RPM is setable.
Based on comments here, it seems that the Mooney uses 2550 as the base RPM.
Although it seems that the common RPMs are 1800, 2050, 2300, 2400, 2566, and 3000.

JPI uses 800 RPM to start tach time counting and EI uses 1200. I have both and my tach times don’t line up between the two.


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[PT20J]

Does the JPI have an external input for flight time? That will give you the lowest legal time for maintenance records.

[Marauder]

Does the JPI have an external input for flight time? That will give you the lowest legal time for maintenance records.

Not sure I understand your question. It has a Hobbs feature that begins counting as soon as the master is turned on. Are you talking about the ability to do like my Garmin Pilot app does, count it as time as soon as I exceed 20 knots or go vertical 200 feet?

I’m not aware of any input for flight time although it does track GPS coordinates as well as speed & time.


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[Dickard]

So my solution turned out to be to follow the manual instructions again and this time it worked.  Both my A&P and I had tried the key sequence from the manual to no avail. Then on Monday it worked.  Go figure.

[Will.iam]

On 8/25/2022 at 7:48 AM, Pinecone said:

The JPIs record Total time from power on to power off.  Also they do Tach Time based on revolutions based on a certain RPM being equal to clock time.  That RPM is setable.

Based on comments here, it seems that the Mooney uses 2550 as the base RPM.

Although it seems that the common RPMs are 1800, 2050, 2300, 2400, 2566, and 3000.

I have an electronic tach in my 252 and it also records time which was what the PO was using so i contine to do so. 
First press is for thousands place second press shows hundreds tenths ones and fraction of ones  

[bcg]

I have an electronic tach in my 252 and it also records time which was what the PO was using so i contine to do so. 
First press is for thousands place second press shows hundreds tenths ones and fraction of ones  

Thanks, I have that same tach and wasn't sure how to get the time.

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[carusoam]

Bcg,

If you have any other EI questions…

We have a really good EI guy around here…

Best regards,

-a-

[ArtVandelay]

When calculating SMOH time, do you use hobbs or tach time?

[PT20J]

8 hours ago, ArtVandelay said:

When calculating SMOH time, do you use hobbs or tach time?

Tach

[Pinecone]

AFAIK, all maintenance is based on tach time.

Hobbs time is for paying rental fees and log book.