Hi Max This is a topic I'm glad you're researching. I've never written a comprehensive record of blade design, but its an interesting topic.
Yeah, I did stuff up on the Rotoscythe design comments I made. The circular blades could be rotated, but not reversed.
What I find fascinating and historically important is that David Cockburn understood angle of attack and the aerodynamics needed for lift and to catch grass.
If the small circular blades created bugger-all lift, the bladeholder most certainly did. Your images of the bladeholder are not good examples; in that the changes are an abomination of the design.
[Your patent images are close to production models].
The thing is that Rotoscythe had an advanced rear catcher mower, with a high arch in the inter-war years. Pope looked at aerodynamic bladeholders in the late 1950s, and Victa for high arch discharge a decade later with their VCs. They would seriously look at bladeholder aerodynamics with the CSIRO collaboration after that.
The gallery below shows another abomination of the design, an original blade holder, and a parts list confirming this.
Many thanks for your great research. It is appreciated by all.
