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jkreidler
Joined: 13 Feb 2008 Posts: 151 Location: Sheboygan Falls WI
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Posted: Wed Apr 08, 2009 5:42 am Post subject: Tach Time |
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I have dug on this topic and can not find an answer. So it might be so obvious that I am not getting it, fortunately I have you guys!
We a GRT EIS, and a Hobbs meter (oil pressure activated). Per the GRT EIS manual we can select a RPM where the unit begins to count 'tach time', however this is an on-off switch, in other words when the RPM rises above 1500 RPM the counter starts, below 1500 RPM it doesn't count. This differs from a mechanical tach which is proportional to a certain RPM.
In a mechanical tach that records tach time, the base RPM is usually set to 2300 RPM. This means that when the engine is running at 2300 RPM for 1 hour the tach time will indicate 1 hour, if the engine RPM is set to 2000 rpm for 1 hour the tach time will indicate .87 hours, if the engine RPM is set to 2700 rpm for 1 hour the tach time will indicate 1.17 hours.
How are other handling this? Is there a regulation? What RPM value seems reasonable? What values are being recorded in engine, prop, and airframe logs?
BTW, if you are using a Westach RPM generator and a GRT EIS, the pulses per revolution need to be set to 11, not 0, 1, or 2 as the documentation indicates.
Thanks, Jason Kreidler
It runs, weight and balance complete, transition training done, doing minor finishing and calibrations, waiting on paperwork.
#40617 N44YH
Sheboygan Falls, WI
(4) Partner Build
Jason Kreidler
Kyle Hokel
Tony Kolar
Wayne Elsner [quote][b]
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_________________ Jason Kreidler
4 Partner Build - Sheboygan Falls, WI
Tony Kolar, Kyle Hokel, Wayne Elser, Jason Kreidler
N44YH - Flying - #40617 |
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jesse(at)saintaviation.co Guest
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Posted: Wed Apr 08, 2009 7:48 am Post subject: Tach Time |
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I'm not sure where the threshold is on the AFS and Dynon units, but they are preset for something that does as you indicate. The on-off switch sounds more like a Hobbs time, which on the Dynon and AFS, counts real time that the engine is running. I know I'm not a lot of help, but I haven't done much with the GRT. There are more experts on the list that can help with that, but since there were no other responses yet, I thought I'd chime in. It might we worth a call to GRT.
do not archive
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
Cell: 352-427-0285
Fax: 815-377-3694
On Apr 8, 2009, at 9:31 AM, jason.kreidler(at)regalbeloit.com (jason.kreidler(at)regalbeloit.com) wrote:
[quote]
I have dug on this topic and can not find an answer. So it might be so obvious that I am not getting it, fortunately I have you guys!
We a GRT EIS, and a Hobbs meter (oil pressure activated). Per the GRT EIS manual we can select a RPM where the unit begins to count 'tach time', however this is an on-off switch, in other words when the RPM rises above 1500 RPM the counter starts, below 1500 RPM it doesn't count. This differs from a mechanical tach which is proportional to a certain RPM.
In a mechanical tach that records tach time, the base RPM is usually set to 2300 RPM. This means that when the engine is running at 2300 RPM for 1 hour the tach time will indicate 1 hour, if the engine RPM is set to 2000 rpm for 1 hour the tach time will indicate .87 hours, if the engine RPM is set to 2700 rpm for 1 hour the tach time will indicate 1.17 hours.
How are other handling this? Is there a regulation? What RPM value seems reasonable? What values are being recorded in engine, prop, and airframe logs?
BTW, if you are using a Westach RPM generator and a GRT EIS, the pulses per revolution need to be set to 11, not 0, 1, or 2 as the documentation indicates.
Thanks, Jason Kreidler
It runs, weight and balance complete, transition training done, doing minor finishing and calibrations, waiting on paperwork.
#40617 N44YH
Sheboygan Falls, WI
(4) Partner Build
Jason Kreidler
Kyle Hokel
Tony Kolar
Wayne Elsner Quote: |
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href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/contribution
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Bob Turner
Joined: 03 Jan 2009 Posts: 885 Location: Castro Valley, CA
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Posted: Wed Apr 08, 2009 10:06 am Post subject: Re: Tach Time |
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This question is, really, of academic interest only, since the "times" are not used for anything (for not-for-hire, Part 91 operations). e.g., there is no requirement (in the US, at least) to overhaul at TBO, nor are 100 hr inspections required, etc.
I seem to recall, somewhere in an advisory circular, that operators who are required to have 100 hr inspections may use tach time or Hobbs, their choice, but I cannot recall exactly where I read that.
You need to keep reliable records; but a long as it's clear what you're recording (e.g., time with the engine over 1500 rpm) it should be okay.
Now, personal flying time - such as time logged to meet the experience required for a new rating - is defined in the FARs as "block to block", e.g., the actual time from which the aircraft first moves, with the intent of flying (taxing to the fuel pump doesn't count), until it comes to a stop at its tiedown, hangar, fuel island, etc., after landing.
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_________________ Bob Turner
RV-10 QB |
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toaster73(at)embarqmail.c Guest
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Posted: Wed Apr 08, 2009 3:59 pm Post subject: Tach Time |
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I had a C-35 Bonanza in which we put an electronics International Tach. I think it began counting at 1200 rpm and up. We basically used its time counter to determine when engine TBO was reached. I plan something to the same effect with the GRT EIS. As Bob Turner said its up to you, you can run your engine to what ever time you want.
-Chris
#40072
[quote] ---
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Kelly McMullen
Joined: 16 Apr 2008 Posts: 1188 Location: Sun Lakes AZ
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Posted: Wed Apr 08, 2009 4:12 pm Post subject: Tach Time |
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Maintenance is determined by regulation on "flight time". That can be recording tach, hobbs, hobbs controlled by an airspeed switch or whatever. There are requirements for entering total time, time in service, etc for maintenance purposes. Perhaps using an airspeed switch to turn on the EFIS recording at say 50kts would suffice.
On Wed, Apr 8, 2009 at 2:06 PM, Bob Turner <bobturner(at)alum.rpi.edu (bobturner(at)alum.rpi.edu)> wrote:
[quote] --> RV10-List message posted by: "Bob Turner" <bobturner(at)alum.rpi.edu (bobturner(at)alum.rpi.edu)>
This question is, really, of academic interest only, since the "times" are not used for anything (for not-for-hire, Part 91 operations). e.g., there is no requirement (in the US, at least) to overhaul at TBO, nor are 100 hr inspections required, etc.
I seem to recall, somewhere in an advisory circular, that operators who are required to have 100 hr inspections may use tach time or Hobbs, their choice, but I cannot recall exactly where I read that.
You need to keep reliable records; but a long as it's clear what you're recording (e.g., time with the engine over 1500 rpm) it should be okay.
Now, personal flying time - such as time logged to meet the experience required for a new rating - is defined in the FARs as "block to block", e.g., the actual time from which the aircraft first moves, with the intent of flying (taxing to the fuel pump doesn't count), until it comes to a stop at its tiedown, hangar, fuel island, etc., after landing.
--------
Bob Turner
RV-10 QB
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http://forums.matronics.com/viewtopic.php?p=238351#238351
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_________________ Kelly McMullen
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