I'm going from 5' to 6' diameter and so just a small 6" length change is all that was required.
Its a three blade system but these aluminum blades always scared me into wanting an extra.
They are balanced around their own CG
Using CAD and keeping the models up to date has payed off because I can go back years and make upgrades like this and they always fit!
I prefer curved sheet metal blades over the molded blades for many reasons:
- I think they are more effective on start-up
- They require no molds
- They are faster to make