I've tried them, they have quite a bit of metal drag ( eddy currents ) but work reasonably well in higher winds. I ended up machining off about .030" from the stator to get a decient start up speed which didn't seem to hurt the performance. The biggest problem is mounting it, it only has a small hollow shaft to mount it with so it can't handle a very large blades set. You would need to change the main shaft to a much larger one with just enough of a bore to allow the wires to come through. There isn't alot of material in the end covers to modify the bearing size so it may take some special bearings to get it all to fit properly.
Overall it was a fun experience. I played with the 300 watt unit although I believe they sell a 500 and 1kw.
Mounting the prop is quite the challenge as well, I used the spoke mounting holes which I'm not real sure is as strong as it should be and would be much better if a special cap could be cast to bolt an assembly directly to it. The end caps are fairly thin as they are and wouldn't handle the load of a yawing prop for very long.
If your not prepaired to "re-work" the motor then its probably not the best choice. It's definately not an "off the shelf" conversion. It would be much easier to work with a standard motor conversion or build your own dual rotor than to use those motors.
Just an opinion from my experience with them...
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