Goodbye to the Emax 2306/2700kv!

In case you somehow missed my opinion of the Emax 2306/2700kv motors: they're completely pointless. Even on ultra-light quads, they draw so much current that any possible benefits they might have are completely negated by battery sag. And on heavier quads, batteries just give up the minute you touch the throttle.

Even Emax seems to agree. They've announced a 2550kv version of the motor. I first heard about this at the Emax booth at Flite Fest, and I asked, "You've got a 2700kv and a 2400kv. Why release something right between them?" I suspect the answer is that nobody was buying the 2700kv for exactly the reasons I've raised.

Having given the Emax motors a fair shake, I didn't even bother flying that quad again until I found something to replace them with. What replaced them is the Foxeer Datura 2206/2700kv motors. (Yes, apparently Foxeer makes motors now. I was surprised too.)

And the result was impressive. Check out my test flight here. (The part where the video goes dark and I crash is because my camera cut out. Oops.) In fact, when I first did a big punchout to test the motors, I scared myself a little bit. These aren't the fastest motors I ever flew, but nobody can look at that footage and say the motors are in any way holding me back. And my batteries could actually keep up... mostly... with the current that the motors were pulling.

When you see the speed and thrust that these motors can make, I think it really raises the question of what we are hoping to accomplish by building bigger, heavier 23XX or even 24XX size motors. Wouldn't you rather save 4-5 grams per motor and use a quality 2206? But then I checked the weight of the Datura and found it's 31 grams, while the Rotor Riot HypeTrain 2306 is 32 grams, so maybe my assumption that 2206 motors will save weight deserves some scrutiny.

Maybe the real conclusion should be that each motor needs to be taken on its own merits, and a simple analysis of the size and kv is inadequate. Thank goodness MiniQuadTestBench exists!