The pattern is based on the original in most cases. You move the orientation of the original instance and the pattern follows with subsequent regeneration.
Make a datum plane (call it blade angle or something) that is in relation to one of your primary planes and to the axis of the fan/turbine. Make sure that the you have an angular dimension between it and the primary datum plane. Then set your relations in the first part of the pattern with respect to the new datum plane (blade angle) that you created. Then you can go in and edit the angular dimension between the blade angle plane and the primary datum plane and the rest of the parts should follow along.