Re: [Phys-l] Bicycle question

[Brian Whatcott <betwys1@sbcglobal.net>]

At 02:21 PM 8/25/2006,  Leigh, you wrote:

> ....Find a stretch of four-inch wide
> white line somewhere on a flat, unbusy road or playground. See how
> far you can ride on the line without leaving the white. You will find
> this to be very difficult for the reason I mentioned; you will be
> constantly turning to avoid falling**. If you try this experiment you
> will understand my explanation kinesthetically as well as
> intellectually, a good thing to do, in my view.

///

> Leigh


I recently accepted much the same challenge: to ride a 4 inch line.
The line in question was a railroad line. I was piqued to read that
 a physician took secret night trips down a railroad on a rail bike
in some slight contravention of the law.

  The bike I prepared for this task had a "feeler" tipped with a
 skateboard roller, and with to side plates at the forward end,
pivoted on the forks at the posterior end. The feeler steered
the front fork.

There was also a side frame arranged to span the rails, and tipped
with another skateboard wheel.

On trials, this arrangement seemed to work quite well, at dusk
on an agricultural rail line not far from town.
 I was encouraged to go faster, and faster....but soon, I came to a
road crossing, where the asphalt rose to rail level, and my front
feeler was disrupted.     Chastened, I tried again, but slower this
 time - until I came to a particular joint in the rails that was
 to say the least, ill-fitted - with a jump up to the following rail.
    This was the moment when my nose came within a centimeter
of the gravel railbed.

Successful railbike design is more artful than I realised.



Brian Whatcott    Altus OK    Eureka!