The wood doesn’t look nice?
We’ve been asked several times about this and did a little research. A carbon fibre or wooden prop would be your only realistic option, they don’t tend to come up very often without damage and, to be frank, they don’t really look the part. We’re not brave enough to mount anything more substantial on a ceiling….this Hartzell hub and blades weighs close on 40Kg. https://www.aerotiques.co.uk/product-page/socata-tb21-propeller-hub
It depends on the prop also. A super light carbon prop for a powered paraglider, or a prop for a C-130 
You will need substantial bearings to support the weight, and a good ceiling attachment method
The bearing will be a thrust bearing, perhaps taper roller.
Mooney_Driver wrote:
Question is however how to drive it as a ventilator
You need an ordinary ceiling fan motor IMO. They are designed for soft start, low rpm, and can handle “any” inertia.
For a ceiling fan, your best bet would be to make a mock-up out of hard styrofoam.
Ask a prop overhaul shop or any maintenance organisation. Particularly the former may well have a few lying around which came to them for overhaul and turned out to be out of specs. Mühlbauer should be able to help there and so should a few others.
Question is however how to drive it as a ventilator. I once tried that with a motor from a washing machine but it turns out that that one turns at much too high a speed. And you wanna be sure the thing stays up… the insurance case if someone gets turned into kebab by a runaway ceiling vent airplane prop would be about as appetizing as the contents of Idi Amin’s fridge.
On the other hand, now that with new regs regarding vintage engines quite some old airplane engines become unsupportable, a nice BMW engine out of a Swiss Junkers 52 might provide ample wind… but I feel sure that my wife would object if i were to install one of those in our bedroom. Apart, they make quite a rukus and your neighbour might have a word to say about the exhaust fumes.
WilliamF wrote:
Have you ever picked up a three blade prop?I have
This !
Have you ever picked up a three blade prop?
I have
You need to get one from the TPs with reverse thrust?
