I used to recommend the FMS 70mm 12-blade unit from Banggood, but they've since raised the price to $45 (plus shipping), and the MRC fan is basically identical in dimensions and performance (I've flown both). For that reason I can't in good conscience point to the FMS fan anymore, even though I still have eight of them in my house in various projects.
Thank you both! I dont know much about EDFs. Are there any advantages to more or less blades? I assume more blades = less torque since the 2 blade pusher version of the x29 has issues with torque roll?
I've been flying 30 years but never flown and edf. I'm hoping for the more powerful, but less torque roll option if there is such a thing.
The difference between the number of blades is a hard thing to gauge because they are all different.
That said, typically the more blades you have the higher your static thrust will be at any given RPM compared to a fan with less blades. Your wattage is also usually higher. The lower the number of blades the more efficient the EDF is, but has less thrust at the same RPM.
This usually means the lower blade count fans have a higher kv motor to offset the difference in watts which in turn usually means a higher efflux speed.
There is also the pitch speed and size of the impellers too which is rarely stated by any mfg.
As a general rule, just think the more blades = more thrust and less blades = more speed at the same wattage.