The prop plane is safer in an engine failure than a conventional twin because it wont want to yaw toward the lost engine.
Hmm, didn't come to think of that, but now that you've "said" it, that's self-evident and a nice idea. Keep spreading the good word, it will catch on! But the aero considerations must be different when the props are "consecutive" as opposed to adjacent. Different blade profiles? Do the props rotate in the same direction or opposite directions?
Btw, do you have to "compensate" for the lighness of the construction? I mean I would guess that with a (and I'm assuming this) lower overall mass for a plane of its size, one would need to rethink wing chord, span and profile accordingly. And those properties would have to be considered against relatively greater differences in loads carried aboard.
