Rotor Tach Sending Unit

This thing has issues, I'm told from fellow builders, and it also has a tendency to pick up stray noise from the electrical system and the wires must be ran as far from the regular wiring harness as possible making it a pain in the butt to install the harness, so much thinking lol.  We ran it as per factory instruction with the exception of that we cut out as much of the standard wiring as we could.  From the rotor head sensor to the bottom of the instrument pod we ran a three wire shielded mil-spec line down the pilots side on the inside of the tube keeping it away from the other wiring harness all we could.  I think it's stupid not to have this unit come with shielded wire with as many folks that have had trouble with the rotor tach reading correctly and it's pretty damn important this thing works right.  I over heard Homer and some others talking about it once and if I got it correct some have fixed the problem by wrapping aluminum foil around the gauge to fix the problem so that means to me the interference is picked up somewhere at the top of the pod and not in the wiring at all, who knows we gave it our best shot and we'll go back later on and run shielded wire from the connector at the bottom of the instrument panel to the gauge and try to figure out how to wrap aluminum foil around the unit without shorting out everything else if we have to.  One also must be sure to get the gap right at the pickup sensor.  It must be close but then again when the rotor head is spinning at full rpm the shaft and or the magnets expand out a little closing the gap and if they hit it wont be good.

Something that happened to us

when we took our ship apart for painting was the nut on the sensor galled when we tried to take the unit apart.  Be sure to put some kind of anti-seize on the exposed threads on assembly or when you try to loosen it to adjust or replace it you'll have a heck of a time trying to get it apart like we did.

Once we started flying our ship we really got to see it work and so far the unit hasn't give us a moments trouble. The only thing I don't like about it is

at night the needles blend into the yellow and green zones making it almost impossible for me to be able to read

and I've had to focus on the unit and hunt for the needles on more than one occasion. I'm pretty certain it's a side affect from the brightness and colors of the FADEC warning lights over powering my eyes, I'm still not sure. I'm planning on making some kind of a shield to place over them at night so they won't be so bright. When I get around to it and get to try it out I'll post the results here and in the Accessories and Add Ons and Mods section of the site