That could be an issue, but the Fantom is a brand-new motor. All the motors I tested are brand-new.

I watched the video again, I must be missing this part. But, if you want you can send me the motor and I will check it out. I'll even through it on my MiniPro.

I would, but I'm not willing to put more money into this motor. I'm probably going to sell it soon. I'm trying to decide if I want to sell the Trinity motors. I'm leaning towards "yes" because I don't think I will be using them.

I'm getting a load master to basically play and compare my own motors. Now, I just want to make sure my reasoning makes sense. If I'm just using a Sky Rc motor checker, I figured that (if I take out considerations like slave motor temp, resistor temps, and such, so in a perfect system), The motor that draws the least amp under load for a given RPM would be the most efficient and the motor that gives the most RPM for a given voltage would be the one that puts out the most power at that voltage. I know that I make lots of simplifications, but am I on the right path? That is using the same resistor bank and same slave motor.

thanks,

Martin Paradis

Sort of, but a high torque vs a high RPM motor might have the same peak power output but at different RPM ranges, so you can't really make that conclusion.

Yes, HP = torque x RPM (in a way)

It finally ends up with the gearing .

There are actually a lot of variables you can look at.
You can check the Kv vs Current, which is great to use for efficiency of a specific motor when setting timing.
But if you want to compare different motors you are also going to need to look at the Kv drop from a no load run to a run with a load. The more the Kv drops, the less torque that motor will have.

With that information we can then start testing and look at the Kv drop under load, and infer from that a torque relationship. Power as said above = torque x rpm. Peak power will be hidden somewhere in the rpm range and this is where you will have to test different throttle levels. We won't have an actual torque value to use, but we should be able to use rpm drop under load as a representation of torque. However, we will have to inverse our results because a smaller rpm drop means more torque. So we will use ((1/rpm drop) x rpm) = power, and remember this is a representation, not actual power numbers.

At this point though, it is all theory. I haven't actually tested the above, I've been pretty busy between my real job, fulfilling orders for my new business, and designing new products. But I do have a new R1 13.5 super short motor arriving today that I plan on testing with. It may take a few days to get to though, but anyone else out there that has the tools and wants to test, I more than welcome your results.

I got a little testing done with my 13.5 tonight. The results were not exactly what I was hoping for, but they were still enlightening.

First, this is a hand picked, super duper motor from R1. It came set at 45° timing on the can, which correlates to about 52° on my Tunalyzer.

These are the results from testing the timing at 5° increments. Test done on my Load Master using a Surpass v6 13.5 as a slave with resistor bank @7.4v

https://cimg1.ibsrv.net/gimg/www.rct...3cb14460e9.png


I tried getting values throughout the RPM range using the Tunalyzer, but 52% at one timing mark didn't necessarily mean 52% at another, so the numbers were not comparable.

Also, the numbers to the far right are the numbers I came up with by taking the Kv difference between no load and a load, inverting and multiplying by the loaded Kv. I was hoping for a clear winner at a certain timing value, but alas, I wasn't so lucky. That is unless 30° really does put out the most power. I'll find out later this week when I hook it up to my MiniPro. But regardless, the Load Master does tell me something, and that there is no way I should run this motor at the 45° can timing it came set at. Look at the Kv drop at the 45° setting. While sure, unloaded you get a big Kv boost at 45°, when you put a load on it, it has the biggest drop in Kv. Looking at the relative power it is way down as well. I would say that this motor is best off timing around the 40° mark on the can, just like previous R1 v21s motors.

I don't think you can draw that conclusion. The settings R1 use are track tested, and all the other settings you've checked in that table are quite low for a stock motor. There's no way they'd be using that setting if it was obviously that bad. Pretty much everyone who uses an R1 in my area uses more than 45 endbell timing.

I'd expect a faster spinning motor to have a bigger KV drop simply because a slave motor produces more braking torque the faster it spins. And since power = torque x RPM, and braking torque is a function of RPM here, you end up with a quadratic function of RPM vs power in these tests. But these tests don't gauge peak power of the test motor, they gauge power of the test motor at the point where the decreasing torque output becomes insufficient to overcome the increasing torque of the slave motor. Peak power is at approximately half the no-load RPM, so I'd expect a ~50% drop in loaded KV if it's really at peak power output. These tests are well below that range.

If we ignore all that and look at it another way, look at the loaded KV vs timing. For each 5 degrees of timing you're adding, you're gaining approximately 100KV of loaded timing. There's virtually no fall off on that specific metric in these tests. Adding timing is still making it spin faster even under a load.

I'm new to the 13.5, as I just picked up 4wd buggy. But the R1 v21s 21.5s that I run, don't like to be timed that high. 40° on the can is pretty much where peak power is generated, and I gear from there. Every motor is different though. But myself, looking at the results. I see that for every 5° of timing added, I get about a 100 Kv increase in both the unloaded and loaded tests, until I hit 45° on the can, which is 52° measured. And then we get a big boost unloaded, but loaded it remains the same increase of 100 Kv. I am curious what the numbers look like in the rest of the rpm range, but I will probably have to get out my SkyRC unit for that test. But the next test will be to put the new motor on my MiniPro and see where an inertia dyno gives peak power. Then compare data.

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.


https://cimg7.ibsrv.net/gimg/www.rct...6e8006902.jpeg

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.

Exalt's motor load test stand looks suspiciously similar to the load master: https://teamexalt.com/motor-load-test-stand-exa9312/

It probably is. He wholesales his products to many different companies.

While I do some OEM for DRC, the Exalt product is not mine, nor made by me.

Copy write issue? What a bunch of losers! There is not doubt that they reverse engineered your design. They suck so bad!!!

While I appreciate your support, my product is not covered under any patents or copyrights. Point of fact, you can go through this thread and get all the info to make your own. I only hope that those who want one will still be enticed by all the pretty colors I offer! And the amazing customer support I provide! Yes, I am biased, but I do give great support.

Note that as opposed to a patent or trademark, copyright exists automatically (in most countries, but not all). No need to claim or register it. Regardless, trilerian has publicly expressed eagerness to share, for which many of us are grateful :). It's getting into nuance, but copyright covers the expression of an idea, not the idea itself.

None of that stops people from having contempt for those who abuse the intent of that. ;)

The question is if the costs of a patent can bring up enough money, within the RC world that is difficult.

My idea of an FDR meter had many follow ups by other home brewers and recently a true MR33 commercial product. I had interests by Muchmore but at the end they went up another way to keep control on an equal performance. For me it still gives me a proud feeling, for sure with the knowledge 3 cheating ENS top names were send home. And of course the people around me know I started this.

In the case of the load master it wouldn't be patentable anyway as there's too much prior art.

I wish I was still selling Electronic Components, I could've helped you save a lot of money getting those resistors and what ever else component wise you require. I always think about getting back in, but I think I took a challange that might be impossible lol. Like some have pointed out, your product is protected since it is published. If I was that other company, I would contact you ASAP and work things out. Example, a certain person in Israel copied a design from a person in the U.K., but the person spoke with the original designer and they came to an agreement. If you need any electronic components send me a PM and I'll see what I can do since I still have contacts of my suppliers.

I'm looking at testing a 25.5 and was wondering what turn motor I should use for a load ?

I always suggest using the same size slave as the motor you are testing. But a 21.5 or 17.5 will still work, it will just put slightly less load on the test motor.

Is their an advantage of a lower over a higher load?

A higher load will bring out deficiencies easier, and sometimes make the data easier to see where the divisions are. But take into mind that a higher load is harder on the motor analyzer you are using. Specifically the Tunalyzer will “stall out” with higher loads. That said I wouldn’t worry about that with a 25.5, just use another 25.5.

Thanks for the fast response