My brushless reads out just fine with just one lead connected.
Also note that now you can easilyu measure the rpm profile without a prop (useful when you just want to make a small change in rpm, but don't want to stress out the battery or deal with a whirling blades. I do this when I make a programming change in my timer, but want to verify rpms and times - better than finding out in the 4-leaf clover that you inadvertently chopped 20 s off the flight time!

I note that I am flying at 8100 rpm with the 12-6 APC prop, and was wondering how you were able to fly at the very low rpm you were originally thinking you had.

Crist,
I am sampling faster than 1Hz (1s), but not as fast as possible (10Hz). With all my sensors (rpm, battery Current & Voltage, Airspeed, Altitude) , I can only hold 2 flights at a time at the lower (5Hz I think) recording rate. However your newer logger (V3) has more memory than mine, so if you track rpm, battery current &voltage,  I would go at 10Hz. Remember you are flying 5s laps, so at 1Hz you would only get 5 points vs 50 points @10Hz. The higher rate will better show what is happening in the corners,  vertical maneuvers etc.

To export the graph, click on the little icon on the bottom of the graph window where you can change the plot setup. When the window opens, there is an "Export" tab. CLick on that, and on chart (I think that is right, I'm doing it from memory right now). There is a button to save the graphic there as a jpeg.

One nice thing about this forum is that you can insert it without compressing to 50kB as over on SSW,

That's right, you need to input the number of "poles" on the Setup software. My Scorpion and AX motors have 14 magnets. The brushless sensor is actually counting magnets (more or less), so if you have the wrong number in the setup, it will scale the rpm wrong. I would have thougt your motor was most likely 14 ---a typical DLRK winding setup, One way to check is to take the number you put in and try ratios. For Example, if you put in 14, but there are actually 12, then the rpm should be scaled by 14/12--the ET logger would count one revolution every 14 magnets. Typical magnet numbers are 14 (DLRK--12 pole stator), 12 (ABC wind--9 pole stator), 10 (DLRK, 12 poles, but wound for a high kV)......

Thanks Walt.  I was thinking of doing just that.  I was busy tonight converting a PC power supply for the bench so I can run my chargers inside without having the hood up.  I'll mess with the tach thing tomorrow.  No word form Eagle Tree about my brushless RPM sensor yet.

Crist
Without looking, I bet you have florescent lights in the garage where you were reading 3600 RPM with the motor stopped.  The sensor on the tach is looking at changes in light level.  Florescent lights go off and on 7200 times a minute as the voltage swings from positive to negative passing 0 volts twice per cycle.  60 cycle x 2 x 60 seconds = 7200.  Your tachometer is displaying the actual count divided by 2 for a two bladed prop.  If available try switching it to three bladed prop and the count should show 2400 rpm.

Old style incandescent lights (Edison lights) have a filament that is white hot making a constant light level output.

Clancy

Alan,
The porblem with the brushless RPM sensor is that when I hook up just the "motor 1" wire the RPM is inop.  When I hook up just the "motor 2" wire the RPM works.  I would think that either wire should work.  With the motor wire 2 hooked up I read thr RPM on RPMa gage.  Go figure.  I  need to talk to Eagle Tree about that.

Clancy,
I have incandesent lights in the garage.  I think in reality, it made no difference on the tach readings.  I calibrated my brushless RPM sensor by saying I have 14 poles instead of 12 poles the motor really has.  I get the same readings with different ESC's so I doubt that the issue is ESC's.

Crist