[4stripes]

Finally got to fly the Changesun 90mm 12 blade fan with the Turnigy XK4074-B-1400kv motor in my Starmax F/A-18 on 6S (Zippy 6S 30C 5800mah).
Very impressed with how quiet this combo is! Very slight motor whine but a huge improvement over any of my wemo-clone fans (freewing/starmax). The plane is almost too quiet. Yes the current draw is higher with about 20% shorter flight times but with throttle management I flew a 5 minute flight without setting off my battery monitor (set to 3.3volts per cell). 4 minute flights only needed 3800mah to recharge (sorry, didn't get the charge for 5 min flight).
The stabilized draw was 84A/1800watts. 2.2kg thrust (in plane).
The fan does require some work. I had to add a shim (washer made from 80 grit sandpaper) between the aft blade retainer and the hub to stop the blades from rotating within the hub. The fan also needed static balancing with epoxy added on individual blades behind the aluminum hub. Although the fan is not as efficient as a wemo midi style fan it does have a much better sound in flight. This 40mm Turnigy motor was a fraction too large for the shroud untill I sanded the outside of the motor to fit (using a bench mounted belt sander). The unfortunate part of the 12 blade fan is any motors commonly used in most 90mm fans (like a wemo) have way too high a kv rating and will fry your motor/ESC/ and battery. Some trial and error led me to chose this motor.

Changesun does also sell a combo with its own motor (they call 1600kv). Their kv rating is suspect from my testing so far with their motor. The one I purchased was very poor quality and was way out of balance. I ended up disassembling the motor to balance the rotating part of the outrunner (by adding epoxy between the magnets). That fan also needed a drop of epoxy inside the hub to secure the hub onto the motor shaft (to fix some play in the oversize hole).
Ground running the stock motor gave similar current draw to the Turnigy motor listed above.
80A/1700watts 2.1kg thrust in plane (also 6S).
The main difference is the Turnigy/fan combo weighs 530g and the stock motor/fan weighs 350g. I removed part of the shroud (aft end) to make the same length as my other Freewing shrouds and reduced the weight by 30g to 320g (exactly the same as a Freewing 90mm fan with freewing 1750kv motor).
Next I will flight test the "factory" 1600kv motor and post my findings.
Cheers Eric