This dual-pitch sounds pretty odd to me.

If you look at a conventional (constant pitch) prop, the angle of the blade reduces as you move further away from the hub (towards the tip). This provides a constant aerodynamic pitch which means that, at flying speeds, the effective angle of attack of that blade is the same across its entire span.

If you use one of these dual-pitch props, the tip will be operating at a higher angle of attack than the root. This means that if the aircraft is flying such that the tip section sees a slip of just 15%, then the root will be operating at an effective *negative* angle of attack -- possibly even stalled.

Of course, when the plane is static or moving slowly, the highly angled root section of a conventional prop is usually operating in a stalled condition -- producing lots of drag and little thrust. I can see that these dual-pitch props seek to unstall the inner section of the blades sooner than happens with a constant-pitch prop and that might work -- but I'm still a little skeptical because...

The reality is that the tips of a prop do most of the work anyway so it doesn't much matter what the root pitch is. Do the math and you'll see that the inner-most 50% of the blade really just comes along for the ride.

These props sound like a triumph of marketing over substance :-)