Hi Michael,

I believe my problem is stemming from the following, based on my recent tests. It seems I have to increase the trailing edge radius (ter) by a factor of 3 and break the circle up into four pieces. Doing these two things allows the sweep op to create the desired geometry. If I don't scale the ter at all then I get very random results. If I scale the ter by 2.5, MoI will create geometry in a repeatable fashion. However, not the geometry it does when the ter is scaled up by 3.

Once I got a handle on everything, all that you have to do is select the circle, select the airfoil and do a two rail sweep. If the ter is big enough and the circle is broke up into four pieces (presumably to match the four airfoil curve segments) then everything is accurate, repeatable, and displays properly. Rebuild and mesh size had some affect, but not really anything related to my problems.

On a different note:

I realized that having the variable pitch blade shank on the swept blade does not make sense in reality. I was doing it just to kick the tires on MoI. But for the sake of reducing confusion I put my novel fixed pitch blade attachment on the swept blade and the traditional variable pitch attachment on the straight blades. The swept design is for the Airbus A400M military transport and the straight blades are for the Piaggio Avanti II business turboprop. Both very cool planes.

Thanks to everyone for your help, I believe I have everything under control now. I'm going to remove all the old pics I attached to save server space. As always these pics are also on the PROP_DESIGN website.

And just to summarize this thread; basically the answer was not to use blend, use sweep instead.