Paul,

you're right about the rudder set-up... I forgot that I added an extension to the shaft in order to get the control horns above the top of the float, and at the same time, keep the rudder as low in the water as possible. The solution that I came up with prevented me from having to trim the rudder... I got it mounted so the front radius drops below the float. To do this I glued two shafts from two separate Ernst rudders together. I'm sure that you can come up with some surrogate material, rather than buying two as I did. Photo for details (forgive the poor quality). Also note that my rudder is made from plywood... this a consequence of getting into a rush... I broke the original plastic Ernst rudder trying to rapidly get the plane loaded into my car. So, don't worry... the plywood rudder is NOT any special performance-enhancing modification!

Anyway, I ran Kevlar fishing line from the water rudder control horns through pulleys (available from Proctor) mounted to a plywood plate. I simply bent some 2-56 wire in a "U" shape, slid on the pulleys, then CA'd these wires into holes drilled in the plywood plate. The plate was then screwed into the top of the float, just behind strut #4. From there, the lines ran through another set of pulleys (red plate in my hand). This plate is screwed to the bottom of the fuse (ply added inside the fuse for bite). From this plate, the lines crossed over one another and then were finally attached to the tail wheel via a tiller bar that I fasioned from an old dual-sided servo control arm. This took some fiddling to get it seated on the tail wheel wire (and set tightly so it wouldn't slip). Laslty, I used a couple of small-gauge springs to relieve the tension on the kevlar fishing line (also should be visible in the photos).

This set-up has held up well to two rigorous float flying seasons. I have been very pleased with both the look and the performance. By the way, I use only one water rudder. I found that it works just fine with only one rudder. So, in my opinion there is little point in trying to double the work, weight and complexity! You're call, of course.

While you may not have the exact materials lying around your shop, I think that you can substitute where required and set-up your linkage similarly.

Regarding the step and 80mm relationship, If memory serves, I simply put a carpenter's square on top of the float (above the step) and checked that the perpendicular rise of the square pointed to a spot on the bottom of the wing that was 80 mm from the leading edge. I think. I may have to think about that some more. I'm pretty sure that's how I did it. Yeah, that should work. I think. You should think about it, too. I'm almost certain that this was how I set it up. Almost.

Hope this helps!

Your beaver looks great in the air!

Let me know how it goes and whether you need additional help or clearer descriptions.

Best,

Noah