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I originally intended to build a wood and steel version of this design on
the Test Mule, then decided to try something different. I printed out the
CAD drawing at full size (in pieces) and glued them to a sheet
of plywood. Next I used more drawings to pieces of cardboard to simulate the triple-clamp and pivots,
then connected everything with thumbtacks. The result was a 1:1 mockup which took less than an hour to
make and cost nothing. Cheap and easy.Turn the "handlebars" in any
direction and the tie-arms pull the center pivot back and forth. The tie-arm
from the center pivot turns the forks.
Here's a CAD drawing of my latest steering scheme. The upper triple-clamp and ball joint are
shown in green. The upper A-arm is yellow and the frame is blue. The
parts for the actual steering, including a relocated triple-clamp, are shown in red.
The handlebars, attached to the relocated triple-clamps, would push or pull on a tie-rod connected to
the upper arm of a vertical pivot. The pivot is bolted to the left side of
the frame. The lower arm of the pivot would push or pull on a tie-rod
connected to the top of the left fork, which thus turns the front wheel
left or right.
I know it appears confusing, but this design eliminates two heim joints and one pivot
from the existing prototype mechanism, which makes it well worth pursuing.
Here's a close-up of an angle indicator which is marked at fifteen-degree
increments. Each "triple-clamp" has the same indicator which allows me to
confirm the front and rear are synchronized. Ideally I want 45 degrees of
movement in each direction, and this design allows it. but the existing
prototype control arms only allow 40 degrees.
Here's an overhead view showing both triple-clamps at fifteen degrees. The
tie-rods had to be adjusted
slightly to ensure everything rotated equally, but otherwise it worked
exactly as planned.
Here's a slightly larger view showing the triple-clamps at 45 degrees. Based
on this ultra-cheap mockup, I'd say the new mechanism should be a success.
I'm so confident, I might skip the prototype on the Test Mule and proceed
straight to building the real thing on ProjectVF.
As shown in this older photo, the mount for the handlebars could be
simple, but can't block the air cleaner or carburetors, or the valve cover
beneath the bars. This will be the starting point for the
future mechanism. Once the handlebars and tripled-clamp are located, the rest will be designed to match.
