[python] Re: 65 degree pivot angle
- From: Kurt Rutter <tokabago@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Thu, 17 Mar 2011 16:55:26 -1000
Hey Vi,
Yes I agree the rod end pivots might be ideal for prototyping, which is
generally as far I get (day job: nurse) but they do look heavy. I finally
weighed my python, 18.5 kg! Ouch sort of a cow. Maybe there exists some high
grade aluminum aircraft version of rod end that would fix the weight issue,
or maybe I am mentally overdesigning them.
Thanks for the plots, is that me shifted off the the right? I win! Did I
win? What did I win? [American ;=)]. I admire the Pythoon very much after
seeing the video. Interesting that Pythoon's pivot angle is 62.5 compared to
65 for Kauai, but has a much longer wheelbase. I moved to greater pivot
angle and shorter wheelbase and improved control (now it's rideable) but
Pythoon is obviously very rideable too. Jurgen mentions the effect of front
end weight relative to center weight ( I guess actually mass). Pythoon has a
pretty nice front end structure that looks light, while my front end is the
heavier part of my bike unloaded, so that may account for the performance.
Also Pythoon used ballast in the middle part for the video (child / copilot)
increasing the mass of the middle relative to the front. Alas, my children
are grown.
Kurt
On Wed, Mar 16, 2011 at 4:50 PM, Vi Vuong <vi_vuong@xxxxxxxxx> wrote:
> Hi Kurt
>
> I plotted your new measurements, along with mine and the Pythoon. Here is
> the link in case you are interested.
> http://en.openbike.org/images/openbike/2/28/GuineaPigPivotAngle.png
> It seems that pivot angle is more sensitive than wheelbase. It would be
> nice to be able to adjust both. Rod end pivot is supposedly good for fine
> adjustment, http://en.openbike.org/wiki/Steering_Pivot
>
> Vi
>
> ------------------------------
> *From:* Kurt Rutter <tokabago@xxxxxxxxx>
> *To:* python@xxxxxxxxxxxxx
> *Sent:* Wed, March 16, 2011 12:03:43 AM
> *Subject:* [python] 65 degree pivot angle
>
> I too shortened my pyhon (by 7 inches to a 111cm or so wheelbase) and
> increased the pivot angle by a couple of degrees to 65 degrees. The ride
> improved quite a bit. I was surprised how how much improvement came from a
> slight change in pivot angle, even though Jurgen has stressed this more than
> once :=) The bike will now maybe fit on the county bus bike rack (for
> slightly lazy commuting). I'm using a rigid mountainbike fork, extra long
> for suspension compensation. If I switch to a regular road fork I will lose
> another 3-4 inches in length but will have to raise the seat about 6 inches
> so the backrest will clear the rear wheel. Compromises!
> Kurt
>
> (\_/)
> (0.o)
> (___)o
>
--
Kurt Rutter, RN, MSN
Kauai Community College
Nursing Department
krutte@xxxxxxxxxx
cell: 631-9131
(\_/)
(0.o)
(___)o
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