This motor was a total surprise! It showed up on my doorstep one day from DYS with no warning, and boy am I glad! It's an upgraded version of the MR2205 series.
DYS seems to have been listening about the thoughts and criticisms of many of the popular motors on the market right now, and this motor is the result. There's a few key features to notice here. The most immediately obvious is the 5mm/4mm hollow shaft. The shaft design is very simialar to the shaft on the T-Motor F40, and the SunnySky Edge motors. Like the Edge, but unlike the F40, the shaft is held into place by a screw and retaining ring. No more messy C clips, just a standard 1.5mm hex head M2.5 screw! This solves all kinds of problems with retention. Also because of the way the shaft is flanged inside the bell, and the way the prop screws directly to the shaft, the days of vertical play in your motors are gone for good. The hollow shaft also happens to be more resistant to bending than a solid shaft, and of course the wider diameter doesn't hurt. To be fair, this innovation started with the airbot motors and their ridiculously large hollow shafts, and the flange and machined threads originated from T-Motor (who also makes the SS Edge motors), so DYS is simply following the trend here, but they've done it very well. Also it is worth noting these use a much thicker gauge wire in the windings. This should help high current applications. An additional feature to note is the magnets. Here this motor has taken it's cue from the venerable Emax RS series and is using very thick N52 magnets in the design. This has its ups and downs that we'll talk about in the test results, but for the most part it's a huge bonus to torque.
As far as the build of the motor, everything looks good. The quality of machining on the shaft is a tad rough, especially where the threads are cut into the shaft, but really only by comparison to the F40v2/SSEdge motors. I didn't have any issues as a result of the threads. The shaft is a tad bid thicker, and some of the props were very tight on the shaft, and removing the props once they'd been tightened down proved challenging with some brands/styles of props. The machining on the bell looke fantastic. Tolernaces were VERY tight on this motor and everything fits together extremely well. Removing the bell turned out to be a fairly significant challenge due to the strength of the magnets and the tight tolerances. I ended up having to leave the X-mount I use on the thrust stand attached to the back of the motor and put the nut on the shaft. Balancing mud is present inside the bell, and the bearings feel smooth and tight. I was impressed with the MR series motors from DYS, but these are definitely a step up from even that standard. The motor weighs in at 30g without the propnut and 32g with it, lining up with the XNova, F40v2, and Emax RS motors.
Now on to the bench results!
Based on my examination of the motor I was expecting great things here, and this motor did not disappoint. It matched or beat the performance of the Emax RS2205 2300kv across the whole range of props. RPMs matched almost exactly, with a few exceptions, where the DYS motor pulled ahead a bit. For the most part any differences between the two motors were small enough that they can be explained by variances in the test environment. One very important note, because of the cooling design on the Emax RS motors, and the lack of any sort of active cooling system on the DYS SE2205, the motor runs much hotter on the heavier props. This is important because both the Emax RS and the DYS SE use standard N52 magnets NOT high temp or SH edition magnets. This means the temperature at which the magnets begin to demagnetize is much lower. This is significant when over-proping these motors. Over time, running these motors at high temperatures could demagnetize the magnets, effectively making the motor higher KV, which in turn would aggrivate the problem. The motor got EXTREMELY hot for me on the 6x4 King Kong run, hotter than just about any other motor I have tested. Also after an initially very high spike in thrust/RPMs the tapering off of the thrust was fairly dramatic, more than the RS, which I suspect is due to temporary reductions in the magnetic field due to heat. I measured KV after that last run, and it was measuring at 2410kv. I am going to go back and measure the motors that I haven't run yet, and see if that represents any sort of measurable drop in KV, or if they simply are higher KV than the Emax. Given that the smaller prop results were a bit higher than the Emax, I suspect that the motor is simply higher KV. Regardless, the heat issue is definitely something to watch out for. To be fair the Emax RS motor sufferes from the same risks, it just mitigates them with the active cooling system, so it doesn't kick in till a bit higher. Check your motor tempertures fon both of these motors as soon as you land if you plan on proping these on anything beyond a 5x4x3 or 5x4.5 hybrid bullnose. All that being said, the DYS SE motor was still very impressive. Even with the heat I didn't smell resin. The thicker windings here are really helping the wiring itself hold up. This is the first motor I've tested that could match the mighty RS, and it solves some of the issues the RS has had with the shaft design.