Originally Posted by
trilerian
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
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.