Jabiru/MGL Revcounter

[Corby202]

Early days yet as I havn't flown but the reading on my RDACXF seems constant using the alternator but I had to put a 240 ohm resistor in the line and the ballast switch up.

[fastj22]

The MGL instructions for the RDAC suggest using the same connection as for a Bendix magneto - connect from the low tension side of one of the coils to the RDAC tacho input via a 10K resistor and remove the ballast resistor link. I actually used a 12K resistor, presumably because that was what I had available at the time. It works perfectly, completely reliable. I have checked it against an optical tacho and it is accurate to the resolution of the optical tacho.

Peter
Sonex 894

So essentially you just installed an in-line 12k resistor on the wire and are having success? Don't remember reading about that in the manual but I probably blew over the Bendix mag part.

I just reread the RDACXF manual on this and it seems pretty simple. I've never gotten a good reading from the alternator across the whole range.
Not familiar with the "low tension side" term, but it seems you just connect were the p-lead is. Will be experimenting myself with this.

Update,
Put a 10K Ohm resistor on a wire from the p-lead to the RDAC and turned off the ballast and on the high gain. The RPM is solid throughout the range. No goofy readings like it did off the alternator.

[vwglenn]

Update,
Put a 10K Ohm resistor on a wire from the p-lead to the RDAC and turned off the ballast and on the high gain. The RPM is solid throughout the range. No goofy readings like it did off the alternator.

In the middle of my annual. I intend to do the same. Will post back the results.