[whpva] Re: 200m "low/zero" altitude *difference* category
- From: Theo Schmidt <whpva@xxxxxxxxxxxxx>
- To: whpva@xxxxxxxxxxxxx
- Date: Mon, 06 Feb 2017 12:06:05 +0100
Dear all,
In my posting of 30.1.17 I said:
I'll come back to the physical course flatness issue ("bathtub course")
in a later posting
What do we really want, i.e. what is the spirit of the 200m rule? I
think it is to measure the maximum speed that can be achieved with human
power in any self-chosen time (any runup) and maintained for a short
time (200m, but could be less). The accumulation of kinetic energy
during the runup is inherent. The accumulation or conversion of
potential energy isn't. This means that the altitude profile of a runup
must not be convex, as it would allow the arbitarly slow anerobic gain
of potential energy and its arbitarly fast release, i.e. free power. I
would nevertheless propose a tolerance of 1.5m in order to be able to
use the lower part of raised banked curves. Also, this is easily checked
by sight, as 1.5m is a typical height of observers' eyes.
Regarding a concave profile (bathtup), I am still of the opinion that
because of the higher speed at the lowest point, the (negative)
aerodynamic and some rolling resistance powers mean that there is no
*physical* advantage as long as the finish of the runup is no lower than
its start. But we should show this e.g. using simulations.
There is probably some *pysiological* advantage and an indirect
*technical* advantage (less gear changing), but I think this is not
against the spirit of the 200m rule.
It is of course a form of energy storage, but not one by which potential
energy can be accumulated outside the timing section as would be the
case with a convex profile or with winding up springs or flywheels
*outside the timing section*. I see no reason for disallowing such
energy storage *within* the timing section.
But first, we should decide whether at all to provide for a new 200m
category and if yes whether to continue to accept the old category at
all or to leave this for the IHPVA. And whether to stick to 200m or use
something else in order to avoid confusion and conflict, e.g. 1m or 10m,
making an easier time trap or even 0m allowing radar/lasers, etc, or
100m (neat) or 199m (allowing comparision but not confusion with the old
records).
I would leave the absolute site altitude out of *this* discussion as it
is a separate issue to this "low/zero" altitude *difference* issue.
What do you all think?
Best,
Theo Schmidt, Future Bike Switzerland
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