tstop4me, I wasn't saying there is little or no difference. I do know very small changes make a huge difference. Differences I can barely see have made a huge difference in how i skate.
I'm just trying to figure out the basic geometry and intuitive physics of blades.
This was originally inspired by the idea of making my own blades for myself - though I'm realizing that's a lot more complicated and expensive than I thought, in terms of tools and even the raw materials.
But then I just got curious. Why aren't short blades just a miniaturized version of long blades? But if that were true, the toepicks woudn't be the same size (which as we were told in another forum, they do seem to be), and a 12 inch (mounting plate length) blade would have twice the rocker radii of a 6 inch blade (just an example; I know most blades don't cover that large a range) - which we know they don't.
I don't understand why they aren't completely scaled like that. The angles of roll would be the same. The places where weight is borne on the foot would be the same. Etc.
One skate tech, who sharpened blades for a major skate boot brand, told me he thought the shapes of the front half of blades of a given model were identical, regardless of scale. But for reasons I mentioned, that makes no sense - why would a little foot bear the weight of jumping in the middle of the foot, while a long foot would bear it in the toes?
There are blade pictures online. E.g., MK, JW and Paramount have pictures of all their blade models, in almost a flat projection - close enough that I could perhaps calculate radii and transition points, if I knew the scale. I downloaded them all to play with. The image formats contain a scale, but they are presumably photographs not scans (because you can also see the mounting plates), so the scales might not reflect reality, as much as the photographers original intended display size. (I thought of using the published main rocker radii to scale the sizes, though I'm not sure the image resolution is fine enough to accurately calculate a main rocker length). Ultima's pictures are in a weird perspective, but other pictures of Ultima blades are available online. But - for the most part, none of these label the size of the blade, and they only display one size.