Click
HERE to see a 5.4 meg video of ProjectVF's rolling chassis during
downhill testing.
The rake on the scale model is about 45 degrees which might be a bit
extreme. I'm giving serious thought to leaving the suspension exposed when
bodywork is added, so a rake like this would look pretty cool. I'm going back to the test mule
and heavily weight the front to
simulate the load of an engine, then retest some of the shallower rakes and caster to find a neutral combination.
Somewhere along the line, the rake went far steeper than I'd intended. It's
steeper, in fact, than the VF750 it came from. I looked back at the testing
data and realized I'd never compared any of the test combinations to the
Interceptor settings. Worse yet, I was too busy with the Test Mule research
to consider how the final design would look. The photo at the right shows
just how upright the forks are, which isn't what I want.Sportbikes with a
rake this steep typically have a steering damper. Since I don't need the
cutting-edge handling of a racer, I'm going to redesign the A-arms to use a more sensible rake. The first step is
to disassemble the whole thing, take measurements, and start over.
I hoped to use the existing control arm mounting points but once I drew the various pieces I knew I was doomed. The
geometry won't work. As shown in the drawing at left (click on it for a
larger version), I can make the trail work perfectly with the rake, but only
if the suspension never moves. If the vehicle brakes hard, or encounters a
bump, the rake drops to an ineffective amount. I need new mounting points.
What I have to do is cut off the suspension subframe, fabricate a new one, then weld it to
the main frame and hope everything lines up. I don't mind the work so much
as the 95-degree temperature outside, but that's the cost of summer instead
of winter snow.
Fabricating a new suspension will certainly delay ProjectVF, but there's no
point going any further with a flawed design. Having built the control arms
once, the second time should go faster. The
steering system should be easy to adapt and this time I'll use heavy-duty
parts to handle the expected forces. With better fabrication skills, better
quality parts, and more experience welding, the new version will be better
in several ways.
This is just a small setback.
