[Roadsters] Help! mechanical genius needed, throttle pedal challenges
gsglasgow at comcast.net
Fri Sep 14 22:46:49 MDT 2007
Just remember the simple fact that if you change the geometry to reduce your
foot effort by half, you will also double the range of motion your foot will
Have you considered changing the throttle return springs? I'm unfamiliar
with slide throttle setups. I assume they still have something of the sort.
> -----Original Message-----
> From: datsun-roadsters-bounces+gsglasgow=comcast.net at autox.team.net
> [mailto:datsun-roadsters-bounces+gsglasgow=comcast.net at autox.team.net]On
> Behalf Of Fergus OFarrell
> Sent: Friday, September 14, 2007 7:28 PM
> To: tomet9 at sbcglobal.net; datsun-roadsters at autox.team.net
> Subject: [Roadsters] Help! mechanical genius needed, throttle pedal
> perplexed you are, but not too far off.
> It is time to get a bit more geometric on this challenge.
> We need to get a 15-25# fish scale, and see how much force the
> stock vertical
> linkage arm is pulling on the carb cable linkage (Keith Williams, got any
> ballpark quantitative number on this?)
> Without this, we get a pc of PVC pipe and some cheap poly rope
> and some small
> weights (arm curl dumbbells or ankle weights) and make set-up
> where the PVC
> pipe is our new 'belllcrank', as close as possible to the same height and
> perpendicular to the cable outage, the poly rope is the cable
> extension, and
> we weight the end of the rope until the pedal feels "neutral".
> Then we know
> std pedal force needed to overcome cable friction.
> Now do the same for your new set-up, in the opposite direction,
> finding the
> force needed to actuate the throttle set-up you have. (when running, which
> seem to be the challenge)
> Then work the geometry, (free-body diagram) measure the radii of the
> bell-crank(s), (partial pulley curves) , lever arms in the
> system, and work
> out what we need. Then go looking in junkyards (and possibly motorcycle
> junkyards for the cable linkage that made that carb set-up work
> at only wrist
> torque) for parts, and maybe Summit and other folks.
> Anyone, am I way off base? Beuller?
> Phergus O'PhysicsPhun, 69 2000, HB, CA
> gsglasgow at comcast.net
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