I would take the percentage difference, of the KV, for the motor underload and not underload. This should give an idea on the torque of the motor. A higher RPM will produce more of a drag, but if the motor has good torque, then the KV would be less affected. However, we all know, the higher the RPM, the lower the torque.

I ran a quick test with an R1 v21s 21.5. I know this motor should be timed around 40 on the can.




And it shows a larger drop in Kv when you hit the 45 mark. I need to test more motors…

it also jumped 1.5 amps.

My load master should come this weekend. Does running a motor as a slave cause any issues?

I have a couple Fantom on the way and was planning on testing / tuning within this new batch (using 1 new motor as a slave while the other is being tuned, then swap).

Or should I find / buy / designate a used / old / cheap motor for the slave?

I have seen no issues using motors as slaves. Just for testing and getting data I use the closest wind motor I have within arms length away. But if you are going to compare results later, I suggest finding slave motors for every wind that you are testing with that are dedicated. Pick up some Slot Machines!

The one thing to take into account is to be mindful of the slave you use. Higher winds = more load on the test motor. I recommend starting out with the same wind slave as the test.
And I hear my printers going nuts right now, maybe yours is being printed, lol.

When comparing motors, I use the same slave motor on all of them. Therefore, I know I'm testing apples-to-apples.

Unfortunately, I have new in box slot machines certified’s for all my 1/10s. These are getting replaced with Fantoms. Fortunately, my son stuck with HW G4s in his vehicles. I was hesitant to open them for slave motor duties for fear of putting unnecessary wear on perfectly fine motors. Good to know the slave motor won’t get damaged

You can use an older motor for a slave motor. It might not provide full resistance of a new one, but it will still provide resistance, and that's all you really need.

Any chance of coming up with a cheap dyno?

Tilerian,
I have a project for you. Can you design a timer that will show how long it take a motor to reach top RPM? I need it to work with something like this:

Amazon.com: DIGITEN 4 Digital Green LED Tachometer RPM Speed Meter + Hall Proximity Switch Magnet Sensor NPN for Lathe Conveyor Belt : Industrial & Scientific

Define cheap, lol. The biggest issue with a dyno is the flywheel and enclosure. The electronics part isn't too difficult, but sourcing a flywheel... Well, there is the software part to, lol. But connecting the mcu to a usb and using a terminal emulator you can get the raw output and use your favorite spread sheet application to come up with something.

An inertia dyno is on my list though, not sure how long it will take to get to it.

Designing a timer to start and report info is easy. Determining max RPM on the other hand is all about how accurate you want it. Most likely the max rpm will oscillate a bit, so you need to decide how to determine the max value.

How about showing a graph on time vs RPM for a period of 3 second. I'm guessing a motor should be at full spool in 3 seconds with a decent load on it. However, it would be nice to see where the RPMs start to level off without having to hook it up to a computer.

I really love the tray you have for the Loadmaster. The Loadmaster fits tight, the Tunalyzer fits tight, and the larger rubber feet are a major plus to cut down on the vibration. Very well made!

Thank you sir! The Tunalyzer base definitely turned out the best.

Thanks for the spreadsheet, makes everything easier.