F4U inverted gull wings

Peter Stickney wrote:


It's all a balancing act - but in ggeneral, you're best off going with
the largest diameter propeller with the fewest number of blades that
you can practically manage.


i) I'm sure I remember seeing, years ago, a picture of a Noorduyn
Norseman with a single-bladed prop. Since you seem to know what you are
talking about (more than I do, anyway), what factors would drive a
manufacturer to adopt such a radical solution?

ii) Radical solutions such as the Unducted Fan proposals mooted a few
years ago, had many curved blades - any idea what gain they were seeking
that justified the loss in efficiency?

iii) How does this work with contraprops? On the face of it they must
interfere with each other horribly, but they seem to fly quite well.
Can you point me in the direction of some clues?