[python] Re: Bipolar update

  • From: Vi Vuong <vi_vuong@xxxxxxxxx>
  • To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
  • Date: Sun, 10 Jul 2011 12:26:59 -0700 (PDT)

Riding hands-free is great, especially when the scenery is nice.  Best comments 
I got from the trip are:

That't not fair - from someone riding roller blades
He's lying on a bike - from a kid
Can we make that bike? from another kid
...


http://www.youtube.com/watch?v=abNt5v9CsHg



>________________________________
>From: Vi Vuong <vi_vuong@xxxxxxxxx>
>To: Python <python@xxxxxxxxxxxxx>
>Sent: Saturday, July 9, 2011 9:30 PM
>Subject: [python] Bipolar update
>
>
>
>
>When disassembled, it managed to fit inside a medium luggage (largest that I 
>have), where the micro python would need another inch or so.  Thus it got to 
>go traveling first.  Fortunately, the total weight is under 50lbs, so no extra 
>luggage charge ($100?).
>
>
>Climbing is rather poor, as front weight distribution is ~40%.  Walking is 
>tough, and barely with a stick at the front.  Carrying the 25lb folded bike 
>uphill is no fun either, so a upright folding bike is better here, especially 
>in the city...
>
>
>Downhill is not too scary anymore with some braking.  I can go faster than 
>going uphill now :)  On the flat, I am comfortable enough to share trail / 
>pathway with pedestrians now (when legal).
>
>
>The 2-piece seat is marginal so I had to pick up a mesh back support on the 
>trip, not bad for 
>$1, http://www.google.com/search?q=back+support+mesh&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=1440&bih=814.
>  A hotel towel would also helps.  Because the seat rest is coupled to the 
>rear wheel, starting is a little tougher even with sticks, and care is 
>required to ensure that the back seat / rear wheel is straight.
>
>
>Luckily, while experimenting with uncontrolled rear wheel, I found that the 
>bike is actually more compliant.  The rear wheel is now mostly free from the 
>seat back, other than some pressure / friction, and straightens out nicely 
>under weight, and seems to move slightly with the front wheel due to the 
>pendulum effect, and probably vice versa (another invisible link like the 
>bango steering http://www.youtube.com/watch?v=jzUr3GI_ulE).  
>
>
>There also seems to be some sort of self-stabilizing effect (PSI reduction?) 
>between the two wheels that deserves more analysis, beyond quick all-wheel 
>steering.  Since the camera is mounted to the rear frame, so it's not very 
>obvious that the rear wheel rotates unless you pay attention to the view 
>through the wheel. http://www.youtube.com/watch?v=vswF-qqcwg0 ;  See the PSI 
>test at 1:06-1:15.  The bike feels quite stable as going straight.  I will 
>repeat the test on regular pythons...
>
>
>Vi
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