Electric Stunt > Gettin all AMP'ed up!

Got my Eagle Tree FDR!

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Crist Rigotti:
I putzed around with it tonight.  Ran some samples on the run up stand.  Pretty cool.  I noticed my rpm was more like 8100 rather than the 6800-7000 on my tach.  I think I know what happened.  I'm indoors and the tach reads 36 just sitting there.  I'll have to open up the garage door and tach under natural light tomorrow to see if it agrees with the fdr readings.  Also when my governor kicks in the throttle is about 63%.  I'm going to mess with it some more tomorrow.  Alan, what is your sampling rate and are you using the brushless adapter for rpms?  I got the brushless adapter and it works slick however I have to use motor 2 lead to the motor for it to work.  Motor 1 lead will not work and both do.  Hmmmm, I just though that maybe my motor 1 channel is doa?  I'll look into that too.

Alan Hahn:
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 Rigotti:
Alan,
I'm sampling at 1 per second.  how do you get the graph into your posts?  I know they are jpegs but it is not eveident how you get the graph into a jpeg.

Alan Hahn:
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,

Crist Rigotti:
Alan,
Messed with the fdr tonight.  The brushless RPM sensor is messed up.  Also the RPM is off according to my TNC.  I'll probably have to adjust it by changing the poles.  Thanks for the tip on graphing.  Like this?

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