This assembly is a 90mm twin stage electric ducted fan unit for RC aircraft. It is made of aluminum, and is designed to spin a maximum of 50,000 rpm. Unlike singe stage fans, a twin stage fan requires stators to straighten the flow off the first stage before it enters the second. Unfortunately, Photoview 360 has a hard time with metalics, so the renders aren't that great, but you can see what is going on.
Because the first stage stator is in the way, the case had to be split so the fan rotor could be dropped in. This was a challenge because the strength of the mount would be compromised if I were to simply split it in half. Instead, I have interlapping surfaces that are screwed in place for much higher strength.