hi,

i have tried and tried but i can't seem to blend the shape i'm going for. i'm trying to see if its possible to connect a circle to an airfoil using MoI. this is for a swept propeller blade (but it would be useful for straight propeller blades too). for the swept propeller blade, the circle and airfoil are continuously bending along a curve. the leading edge of the airfoil is an ellipse and the trailing edge is an arc. you can use the script bemfarmer created about a month ago to get a general swept or straight propeller blade. the airfoil curve is in four segments.

the closest i can get is to break the circle up into four segments. sweep it. then do the blend on each curve. the suction and pressure side of the airfoil are close then i have to do a network curve to get the leading and trailing edges in as the blend doesn't work there. the problem is the resulting geometry is not tangent everywhere. i'm not an expert with the terminology but i'm thinking i need g3 or g4 continuity based on reading over the forum here. i only get g1 and g2 options when doing the blend. the g3 option only seems to appear when working with curves. MoI won't let me do a blend or network with all eight curve segments selected. I can do a loft. The problem there is it is only connecting the curves with straight lines and that is not helpful, a smooth transition is needed in all directions.

i tried working with curves as well but i don't get anything that makes sense that way. the g3 option shows up but i can't seem to get anything i can understand or use out of it. so surface edges are what i have been messing with.

trying to figure out the curves and doing a network command is all i can think of. but that would be really difficult if not impossible. which makes me wonder if that is why i can't get it to work in MoI. maybe what i'm trying to do is not possible right now with MoI.

i know this is hard to explain without pictures and a model. but if anyone can try this even on a straight propeller i would be curious to see if its even possible. the circle is centered at the 1/4 chord point and ends at the leading edge. so its diameter is much smaller than the chord of the airfoil. this leaves a lot of curvature trying to connect the trailing edge to the circle. if you have ever seen a typical traditional aircraft propeller blade, that is what i am trying to experiment with.

thanks,

anthony

edit; here are a few pics with the loft