Information received:
"With regard to the subject it would I think have been helpful to have a photograph of the underside of the blade base showing the numbering in true context. I wonder if there are some missing hyphens in the text.
Nevertheless, it seems to me this is a Curtiss blade for a prop of around 8ft 6ins diameter or thereabouts. My guess is a 2 blade prop for a trainer or similar.
As always, I hope this helps."