I could do with something like that to use as a test bed for my 31

I got brave and put my mechanical tacho on the prop nut........... it's a different hand carved prop 18" X 8" WW1 style profile but I cannot get it to swing any faster than 6100rpm. Perhaps it will unwind a bit in the air or maybe try a 18" X 6"

I have also made a manifold to get the carb inside my intended steed the SE5a and the prop awaiting stain and varnish (see below):