[python] Re: Cool handlebar for 48deg 20in
- From: Vi Vuong <vi_vuong@xxxxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Wed, 16 Mar 2011 21:14:30 -0700 (PDT)
Hi Jürgen,
OK, we should advertise the pushable requirement, perhaps in the pivot angle
page. I tested pushing the bike on concrete surface today, and it's not very
easy to maintain a straight line for long.
Yes, DirkB's website recently came back online, so I was able to download the
program to play with. It must be a newer versionbecause it is now written in
C#
and compiled for Windows (exe). Luckily, I can compile and run in Linux
MonoDevelop. It would be nice to do some dynamics simulation of stable and
unstable settings/conditions. Experimental measurements would be good also,
say
gyroscope and accelerometer (iPhone).
Regarding wheel flop, my BB is very close to the hub so the impact of long
wheel
base seems not as much as pivot angle. I was eager to learn some more today.
I
can turn left / right with just a touch of my glove on the ground for
assurance,
and learned to push harder on the pedal to get back in line.
Went over road bumps and speed bumps also, so 20in wheel seems OK. Will do
off-road test this weekend. Good seat contact seems crucial for controlling
the
bike, the arms also. Funny how the training wheels now give me less control
than free arms, so it can be retired. Maybe there is an invisible handlebar
somewhere (quantum?). The gloves however are very useful, not sure when they
can come off.
Thanks for the advice and safety concerns. In general, I am afraid to be in
traffic on any bike, not to mention this one, so I will stick to empty streets,
curbs, and trails...
Vi
________________________________
From: Jürgen Mages <jmages@xxxxxx>
To: python@xxxxxxxxxxxxx
Sent: Wed, March 16, 2011 1:49:52 AM
Subject: [python] Re: Cool handlebar for 48deg 20in
Great!
The last seconds of your video shows something essential: If the python is
pushable it also is rideable.
Also great to see that you have used Dirk Bonnés calculation program, which
funnily enough is written in the programming language python:
http://en.openbike.org/wiki/File:GuineaPigPivotAngle.png
But also keep in mind, that the combination of pivot angle and weight
distribution is crucial for rideability. A heavy front part needs bigger pivot
angles for wheel flop compensation.
And lastly keep in mind that it takes several hundred kilometers of practice to
feel save in traffic ;-)
Cheers,
Jürgen.
On 16.03.2011 03:10, Vi Vuong wrote:
> Magic, I can ride it on first trial :) Ground clearance also improved, but
> seat
>angle became a little too upright ~40 deg to stop me from sliding off forward.
>I
>can also push it forward by the headrest. Perhaps this is a good objective
>test
>for ride-ability, independent of hip coordination...
>http://www.youtube.com/watch?v=6yBjSGL_pd8
>
> Vi
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