re: propeller - check out here for some previous discussion on some different techniques:
http://moi3d.com/forum/index.php?webtag=MOI&msg=5700.10

There have been some tools added since those discussions take place that can probably help though - one is that you can build the propeller as an initially straight slab and then use the Transform > Deform > Twist command to twist it into its final shape.

Another way that will let you have more direct control is to put in several profiles that are rotated from each other and include a point object at the end, then use Construct > Loft with the "Loose" option and include the point in the loft, here are some examples of that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6082.10
http://moi3d.com/forum/index.php?webtag=MOI&msg=6082.8

- Michael