to the sloping rises 22 of the inner cam 21 of the dual cam 20 determines whether the inner and outer lobes 101 102 of the follower shaft 103 rotate continuously in one direction or rotate back and forth in each successive pitching motion the inner cam 21 is typically out of phase with respect to the outer cam 23 by 90 degrees the sloping rises 22 of the inner cam 21 typically also coincide with the opposite sloping rises 24 of the outer cam 23 and vice versa which allows the inner and outer lobes 101 102 to rotating roll without interference the dual cam 20 design allows for the inner and outer lobes 101 102 of a follower shaft 103 to rotate twice in the same direction whenever the lobes move over one of the sloping rises 22 24 of one of the inner or outer lobes 101 102 which coincides the sloping rises 22 24 of the opposing toner or outer cam 21 23 the sloping rises 22 24 are positioned such that they are typically 180 degrees apart but can be as little as 60 degrees apart a turbine blade 10 connected to a follower shaft 103 rotates when the inner or outer lobe 101 102 interacts with the sloping rise 22 24 of the inner or outer cam 21 23.