US Patent 11434923 Fan rotor for ram air fan

A fan rotor for a ram air fan includes a hub and blades extending radially outwards from the hub. The hub includes an inner hub portion, a disk portion connected to a radially outer surface of the inner hub portion, and an outer hub portion connected to a radially outer surface of the disk portion. The outer hub portion has an upstream arm with a compound contoured surface. The compound contoured surface is configured to direct air flow around the compound contoured surface and along roots of the blades.