Aermotor 12-foot 14-foot

[NV-WindmillProject]

I thought of this question when out photographing windmills: is there a way to tell a 12-foot and 14-foot Aermotor apart? To me they look exactly the same.

Thanks in advance

[Newbie]

I have a 12' aermotor on the casing is 702 D so I imagine the number on a 14' of the same mill would be 702 E

[NV-WindmillProject]