How did you have your tach hooked up?

 

I have it hooked up to one of the AC Delco ignition coil trigger signals.  According to Tracy, this will give one pulse per revolution.  I figured that I’d set the tach up for “4 cyl”, which should look for 2 pulses per rev.  Naturally, that will give me a reading that is exactly half of the real rpm, but that’s easy to mentally correct.  At the same time, it’s very close to being the actual prop rpm.  I’ll have to look again at the switch settings, but I think I have the tach configured properly. 

 

 and how are you going to hook it up next?

 

The tach has an optional mode of using it with the alternator output.  It counts the less than perfectly regulated pulses that the alternator leaves on the buss.  You have to do some trial and error with this method, and even some manual adjustment of a pot, which of course requires a way to actually measure the rpm while doing this.  I still think the easiest way to make this work should be with the ignition trigger, so hopefully, I’ll get that going. 

 

 Which tach is it?

 

It’s a VDO “cockpit black” series unit, as are all my temporary gauges.  My requirement was to get VDO, because it would give me the proper sensors, and to get matching gauges, so I can either use them in the Airbike, or sell them as a set.  I’d hate to figure out what I’ve spent on these temporary gauges and sensors, but it’s probably in the $250-$300 range. 

 

I'd like to know as I may need to buy some minimum instrumentation to put in the panel so I can get my final inspection, before I receive the EM-2.

 

I’ve realized that I could add a fuel gauge, and be legal, so I may end up doing that if the EM-2 doesn’t appear in time to have my inspection.  Here, we can fly the minute the inspector hands us the paperwork, but I don’t intend to fly before the EM-2 arrives, unless Tracy adds some more features :-)

 

Rusty