Electronic Tach
- Thread starter Sikorsky
- Start date
BC12D-4-85
SPONSOR
Fairbanks, AK.
You'll be amazed at how many friends you have when they find out you have one
Gary
Gary
skywagon8a
MEMBER
SE Mass MA6
What type of lighting do you have at your airport? If it is of the mercury vapor type (perhaps other types will work as well), face the plane towards the light (at night) run the engine at various rpms and watch the blades. When on a multiple of 60 (60hz) the blade will remain still. When not on that multiple the blades will appear to move backwards or forward. So, running it at 600, 1200, 1800, 2400 the blade will be still. Compare that to your tach reading. If the tach agrees, it's accurate. If it doesn't, make note of the difference. With a two blade prop, 600, 900, 1200 etc.
akavidflyer
FRIEND
Soldotna AK
Tru Tach. I have yet to see a mech tach that was accurate. Mine was off 250 RPM on the top end, others I have done were 150-250 RPM off (mech tach reading high). If you have an engine analyzer picking up off a crank sensor or the mag they are accurate.
skywagon8a
MEMBER
SE Mass MA6
I thought the tach was off in my 185 so I installed a Horizon electronic tach leaving the mechanical tach in place. Running both tachs for a while, they were in total agreement with each other.
akavidflyer
FRIEND
Soldotna AK
I guess I was referring to the piper tachs. It's pretty rare from the 15 or so that we have tested when playing with the prop pitches that the piper tachs are even close.
mvivion
SPONSOR
Bozeman,MT
sjohnson
FRIEND
Boise, ID
This UMA tach is a 'digital' tach with a needle, and comes with an electric sender that screws into the tach drive, eliminating the coax. You can order it pre-marked with a 2700 redline.
It's worked well for me, and I prefer needles to fussy digits.
https://www.aircraftspruce.com/catal...clickkey=10133
wireweinie
FOUNDER
Palmer, AK
cubdriver2
FRIEND
upstate NY
We had a Tru Tach and my $20 RC tach side by side on a few different aircraft. Within 40 rpm of each other, on one plane it flipped who was high and who was low.
Glenn
,
Cub Builder
MEMBER
North Central AR
I have owned several of the UMA tachs. On the O-320 on my SC clone, I couldn't get the transducer to clear the angle oil filter adapter. I sent it back to have the tach adapted for a magneto transducer that fits into the Slick mag. Simple transducer that screws into the side of an existing hole in the mag and picks up the magnet passing by, so works whether you are running on that mag or not and is accurate. (count had to be changed on the tach as the tach drive transducer provides 4 pulses per revolution while the magneto pickup provides 2 pulses per revolution) They also have the same kit for the Bendix mags as well. If you have an analog panel and like an analog tach, that's my go to tach. It comes with the face marked for Continental or Lycoming, or they will paint one to your specs.
-Cub Builder
S2D
MEMBER
Montana
wireweinie
FOUNDER
Palmer, AK
S2D
MEMBER
Montana
BC12D-4-85
SPONSOR
Fairbanks, AK.
What adjustment is done to calibrate the tachometer.....anybody know?
Edit: Found this explanation> https://www.aircraftsystemstech.com/2017/05/mechanical-movement-indicators.html
Calibrated spring noted, so maybe that's what gets adjusted at a specified rpm.
Gary
Edit: Found this explanation> https://www.aircraftsystemstech.com/2017/05/mechanical-movement-indicators.html
Calibrated spring noted, so maybe that's what gets adjusted at a specified rpm.
Gary
Last edited:
Similar threads
