We believe this is Charlie’s first prototype. His wife Eleanor is riding it in 1958. His patent drawings follow this design very closely. I can’t tell what engine is in it but the miter boxes look like off the shelf industrial units. His patent references a 1948 patent that features a belt driven fluid drive mounted on the transmission. I think the same wheels or same design wheels were used on bikes 1a, 2a, 2b and 3a. I see 3 different wheels on the 6 prototype variations. I called them X, Y and Z on my spreadsheet.