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Tachometer
Posted: Sun Oct 14, 2018 1:57 pm
by 6277
My tachometer hour meter seems to be running slow. Today I flew 1.1 hobbs time and only .4 on the tach. Replace or rebuild? I like the looks of the tach and it seems to be orginal. Any ideas? 1947 Cessna 140 C-85-12F.
Re: Tachometer
Posted: Sun Oct 14, 2018 8:05 pm
by 6643
Look on the back for a little hole that says "oil".
OTOH, the way they work, if the hours are slow the tach RPM indication should be too. Something to think about. Also, if you fly around at 1900 RPM the hours won't rack up as fast.
(Are you sure the Hobbs is accurate?)
Re: Tachometer
Posted: Mon Oct 15, 2018 6:55 am
by 6277
Good points. I think the Hobbs is pretty much accurate, although I will double check it next time. I usually fly at 2400 RPM so at that RPM should the be at about 1:1? That is 1 hr of flight and 1 hour of tach time?