I recall having seen aftermarket suppliers of laminated and hand- carved real wood props for a variety of scales. Also resin ones...probably check someplace like Shapeways.

A short Google search should turn up these and other possibilities. Would also be a good idea to check the various WW1 modeling forums, since the question is likely to have come up before.

Cheers

Hi;

 Do you have easy access to a local small airport? If so you might find one in their gift shop!

You could check suppliers for R/C planes as they have scale equipment for up to 1/4 scale. Been out of that part of the hobby for a long time so I don't recall many names but Tower Hobbies comes to what's left of my mind. 

Hope that this helps.

Jim 

Stay Safe.

I used a wood rc prop on the two 1/8 williams bros engine kits I have built. I merely sanded off the brand markings  on the WW1 kit and refinished it.  The pw Wap jr was a bigger job since it required a variable pitch metal prop I cut it in half and rounded the inner ends to fit into the hubs. TThen I put a super glossy black undercoat and Alclad.