DYS BE 1104 7500kv brushless motors

Introduction

1. The DYS BE1104 is a brushless motor designed for micro quads and was available on the first genuinely fast micros - the arfun90 and arfun95 pro. Speaking from having owned these motors for 3 months across 2 quads I can say they are impressive. Motors do have a 'sweet spot' application and I'll talk about where these worked well for me and where they did not.

First Impression
My first impression here was not great - I was not used to the notchiness or seemingly noisy bearings and I had heard bad things about the wires. This was largely solved during build and first few flights - the bearings settled down, the notchiness was the sign of strong magnets and the wires were manageable although still difficult to solder compared to multicore silicon wires.

Flying on a 2 inch quad
These firstly went on a 2 inch quad here but it felt like it was working to hard just to stay hovering. It was super quick on punch outs but general flying was not enjoyable. My thoughs after some time that the motors were too much for the props (King Kong 1935 or Gemfan 2035) so decided to try a larger build

Flying on a 2.8inch quad
I transplanted the running gear over to a FD120 frame which is more commonly know from the excellent PNP leader 120 on this build here. The improvement was immediately noticeable - hovering at a lower idle and flight with a lot more control and resolution, really shining with the larger 2.8 inch King Kong 2840 props. It is fast on 2s and mental on 3s. Although I am a big fan of lightweight for micro builds especially, this build could manage the weight a lot better... batteries ranging in weight from 48g 2s 950mah to 18g 2s 300mah was not as different as you would think.

Final thoughts and recommendations
Firstly I would encourage soft mounting for absolutely all brushless motors. Here is a link for 11xx series motor soft mounts on thingiverse, I got 12 printed for less than $US3 on 3dhubs. Secondly I think these are too much for a 2 inch prop. You may have a different experience but this is mine. I thought a 2.5-2.8 inch prop is right at the sweet spot or 3 inch for a 2 blade like the gemfan 3025. I find the motors themselves well built and very powerful. They have the ability to draw a lot of current, especially on 3s. Because of this I would recommend these 7500kv version for 2s although they are certainly capable of 3s without overheating - I do actually run 3s more often than 2 on this quad. Having had my time again I would have gone 6500kv for mostly 3s as they are more efficient: less current, more torque, longer run time with a small hit on top speed. If I was building the same quad tomorrow from scratch in 2.5 inch and 2s, I would by these again. For 2 inch I would rather go for a lighter build based around 1103 motors.​

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