glum - the props are indeed contr-rotating, but this does not explain the unusual configuration of outer supra-convergent and inner supra-divergent props. All aircraft with supra-convergent props do indeed have contra-rotating props, which is why your comment was irrelevant.
Algy's post does however explain the reasoning behind the configuration, which is interesting.
As an ex-para I can see the mission flexibility of dropping sticks out of the side doors and loads out of the back ramp - though hopefully the design allows the loads to be dropped first
