Ninjasword71

Has anyone tried a design with the propeller inside a round tube with airflow exiting the rear? https://ibb.co/epMkaQ
hope the link works. Just a crappy drawing of the idea.

ByLoudDesign

It iz called ducted fan

Ninjasword71

I know that style but not a regular 9" propeller inside the round tube body running the length of the plane. Just wondering if that works too because I have yet to see one.

mgnostic

There are a few planes where the line between a ducted fan and a ducted propellor is a little fuzzy but one plane does actually meet your description, it is called a Stipa Caproni. It looks like shrouded propellers were investigated during the 1930's. IIRC the shroud or duct negates the need for a high aspect ratio propeller blade and a shorter low aspect ratio propellor with multiple blades is more practical when it can run in a duct.

Ninjasword71

Yes! Thank you. That's the one. Been thinking of trying to build that. That's why I was wondering if anyone has tried on here. I'm not looking for more force exactly but the idea of a air through body.

flyingpiggy

And The Edgely Optica from the UK

Dave

mgnostic

There are some interesting websites. Go take a look at stipa-caproni dot com. apparently someone in Australia built a replica. The original was unexpectedly draggy and overly stable but it was only intended to be a test bed for the idea. With smaller size the drag is less of an issue and a little stability never hurts with a novel plan form.