He's only got a 30" diameter. Asymmetry might cause some vibration but shouldn't be enough at those specs to blow apart. I mean an earlier post alluded to the fact that he would be balancing the fan. If it is well balanced, the tensile strength calcs should be sufficient.
I'll also be running the engine/shaft/fan combination on a test stand before committing to the airframe it's designed for. In case there are torsional resonance/vibration issues that I cannot find a simple solution for.
Motocross for me. The CRF in my name is for the bike I owned when I signed up here, a CRF250. Many bikes later and now I ride a KX450f now but the name stays the same. I've been riding for over 15 years and this never gets old <iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/teWBaanfFEg" frameborder="0" allowfullscreen></iframe>
I had given you the benefit of the doubt there. Nobody with your history on this project is going to run an initial fan test during first takeoff. That is just dumb. Obviously you are going to throw this thing on a mount and run it up to 8,000 rpm.
I don't like to get personal with hobbies but thought I'd throw this out there. I cut three pieces of plywood today. I cut them all the wrong size and had to cut them again. Good thing I had plenty of plywood on hand. This took about 3 hours. Then I had to drill one hole, from the ceiling between the rafters into the attic. I had a 6 inch spade bit, either it didn't reach or I hit a nail (I couldn't tell). So I found a 12 inch hs steel bit to finish the job. When I pulled the bit out of the hole and looked, I drilled right through the roof and could see trees. I redrilled the hole, this time into the attic. I was running some new cable line. This hole drilling project took 2 hours. I asked my Dad if he had any hobbies. He said "Son, some people like to play golf, I like to drink beer." Needless to say I didn't get my woodworking skills from my Dad.
Lol, Nutmeg Had those experiences also, and many more, but yet I don't have enough sense to let someone else do it to this day. Learned what it must be like to shot, at least by a dart gun, while using the tablesaw. Small piece flew back at me and put a nice hole in my stomach, through my shirt. My Dad is like yours, but he always tells me to fix things myself, yet he never did it himself when I was growing up. Actually he did, if he could use duct tape, he would "fix" it. On of the original duct tape generation. He had a bag filled with at least 10 different colors of duct tape for all situations.
Fan is mounted to the engine and I'm working on getting the shaft aligned using a dial caliper. After which I'll mount the bearing, already attached to the fan, to a stand supporting the fan on both ends.