After weeks of plotting and analyzing literally hundreds of motor efficiency graphs, I find that a few motors stand out in my mind as the ones that I would choose above all others. Although they all exhibit excellent thrust and efficiency test data, it’s more than just that – almost a gestalt process where, after weeks of analysis, some firm conclusions have crystallized in my mind. Interestingly, of the three motors that I cover here, two would not have been in contention had I been asked for my favorites at the start of the process – one because I didn’t know about it, the other because I had a negative preconception that turned out to be wrong.
In this post I have not restricted myself simply to thrust test data, but also take into account other factors such as weight and technological innovation. I’ve also restricted myself to motors in the 25-35g weight range. Although I have plotted efficiency graphs for heavier motors, they’re not suitable for my current build so I haven’t given them sufficient thought to have reached a definite conclusion.
Best Light Weight Motor
The BrotherHobby Returner R4 2206-2300, which is also marketed as the Hyperlite V4. With a hollow Titanium alloy shaft for light weight without compromising strength, and a 2206 sized stator in a weight class dominated by 2205s, this motor offers good efficiency and fairly high maximum thrust on medium weight 5″ props – my choice would be the classic 5x4x3, giving 1200g thrust at a efficiency of 3.0g/W.
Best High Power Motor
If you are after sheer power, without any concern for weight or batteries, then the T-Motor F40 Pro 2306-2400 is the motor for you.
I haven’t even bothered plotting the 2-bladed props, because these motors are designed for heavy 5″ props, and in any case if this is your choice then you’re certainly not going to hobble it with 5×4 twin blades. Nope, you’ll be choosing the Lumenier 5x5x3 Buttercutter or the DALProp 5x4x4 to get the most out of this beast.
Best Overall
Something I have learned as a design engineer is that great design is 10% innovation, and 90% finding the right trade-off between conflicting objectives. For example, in motor design the objectives include maximizing thrust, efficiency and durability whilst minimizing weight and manufacturing cost. As a designer, you always get to the point where improvements in one parameter will have a negative impact on other parameters, which is why finding the trade-off that optimizes the overall utility of your design is 90% of your work. The other 10% is to look for innovations that change the design space by removing or relaxing some of the constraints so that new and better solutions emerge.
In my mind, the Armattan Oomph 2206-2300 has done just that. It’s found a trade-off between thrust, weight, efficiency, durability and price that makes a lot of sense to me. It’s not the lightest motor, or the most efficient, or the most powerful. However it combines these attributes in a way that, to me, represent the best balance between them. And it does this by introducing an innovation – the short prop shaft with an inner thread – that both reduces weight and improves its durability compared to its precursor, the BrotherHobby Tornado T2. The only minor negative is that since it uses a screw to secure the propeller instead of a lock nut, you have to use different clockwise and counter-clockwise motors, which means more spares to keep!
This motor seems to love medium-weight 5″ props, especially the 5x4x3. But since it also does very well with the 6×4, I think that the Lumenier 5x5x3 Buttercutter, which is somewhat heavier than the 5x4x3 but has exceptional mid-range efficiency, might actually prove to be the best choice. Unfortunately Mini Quad Test Bench has not yet tested the Oomph 2206 with the Buttercutter prop, so I can’t be sure of this, but it would definitely be worth trying.