Here are three propellers. As in my understanding, the AoA or the pitch of a propeller should be close to its rotation's direction, around 15 degree on the root and less on the tip, more or less like what shown by picture 3. But this propeller with 6 blades (second picture) seems the AoA or pitch is not as that 'rule'. The AoA is close to the axis rather than to its rotation's direction.
Then my question is, how such propeller works?