Tach time

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    • November 13, 2018 at 17:58 #10959
      Eric Rine
      Participant

      I’ve discovered my Tach is not correctly metering the time. It is about 60% of my Hobbs time. I also recently flew one flight to verify, flying at 2300 RPM, so my time on my watch and the tach time should be identical. And I still was getting about 60% compared to the Hobbs.
      Is there a repair process, or is it just more practical to buy a new Mitchell mechanical Tach? Other suggestions?
      Thanks!

    • November 14, 2018 at 06:47 #10963
      Jeff Johnson
      Keymaster

      Tach time is a function of RPM and won’t match Hobbs or your watch. It will be lower. It should be very close at cruise RPM. In my case that is 2500-2600 Older tachs will often read lower RPM than actual so you might want to check to see if RPMs are accurate.

    • November 14, 2018 at 10:37 #10964
      Eric Rine
      Participant

      Jeff – thanks. Agree it should be lower, but I think I’m significantly lower. The tach time appears to be about 60% of the Hobbs. I wouldve estimated 80-90% as you alluded…. I believe 2300 RPM will result in 1 hr of tach time equal to one hour on the closk/hobbs. On a recent cross country, I logged about 24 hours on Hobbs, with only 14 hours on the tach…

    • November 14, 2018 at 10:42 #10965
      Eric Rine
      Participant

      But that raises a good question. What is the RPM that equates to 1 hr on the clock? My initial research showed 2300. But if it is up around 2500 or 2600, then I may actually not have an issue….

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