You need to know how many Newtons you need to apply to this very seat to calculate the strength of the hub with these data.
Firstly. You need to make a calculation scheme.
If the blade is welded, the structural dimensions of the seams are enough. The circumferential force can be estimated by the power of the drive.
Simplest:
a=V^2/R
F=m*a
But the most important thing is to take into account the force of inertia!