Those blades are a direct copy of the original 403 blades. Thermodyne or Hydrogen Appliance uses them on there Hornet. I owned a Hornet. It took 13 MPH for cutin. 5 of these blades will startup sooner but they are so thin and skinny you won't see any power at low wind speeds. They might start to turn at 8-9 mph. They do make a bunch of power at 20 to 30 mph for there size but by then they will be screaming like a banshee.
That's why I developed my blades.
Jerry
Agreeing with Jerry. Over the years I have used them, some I've cut back to 26" per blade, sometimes running 6 sometimes ruining 3. I've had varying results depending on the alt. On my AirX/403 the cut back ones seemed to perform better than the stock 22" blades . I don't have a set of Jerry's blades to compare to, but depending on the turbine, these still aren't my favorite choice. The are usefull for small a high cut-in mill, and they are loud when at speed (rounding the tips slightly helps a little).
Really depends on the turbine though, for most, there are better choices, in some case even PVC blades.
