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Re: WOS Time Slip Data Massage...

To: Land Speed List <land-speed@autox.team.net>
Subject: Re: WOS Time Slip Data Massage...
From: rtmack <RTMACK@pop3.concentric.net>
Date: Sat, 06 Oct 2001 21:49:49 -0500
Mayf:

O.K., now you've got my curiosity up.

You could do "best curve fits" on the data for several of the cars that
completed the 5-miles, and see if the (extrapolated) one-mile speeds
produce a "normal distribution" around 80% of the (individual) top
speeds.

On the other hand, I don't think that would produce anything realistic,
because a single acceleration equation probably can't accurately
describe the speed at any point in time for a multi-gear car.  Our  runs
("Yellow Rose of Texas")-- using 3  gears each run--  produced speed vs.
mile data that looked like 3  completely different log curves, within a
single run.  Shift-points mark the breaks in the shapes of the curves
(and breaks in any derived characteristic equation).  Furthermore, the
shifts all occur before we hit the first mile.

However, I checked our front-wheel speeds at the one mile and the 5 mile
for 1 run from Speed Week and 2 from World of Speed.  One mile percent
of 5 mile speeds were 73.6%, 72.3%,  and 73.9%.  Like many teams, we try
to "lengthen the course" by accellerating as hard as practical.

Although this is not a statistically-significant sample, maybe you'll
find it interesting.  To make it statistically-significant, you could
ask others with data-loggers for this data on their runs.

Russ Mack
Higginbotham & Smith LSR Team

DrMayf wrote:

> Well, I finally got the data sorted to my liking, although I haven't
> really
> plotted it. In fiddling with the time slip data I made a few internal
> ground
> rules. That is a vehicle needed to make it at least to the 3 mile
> flags so
> that car would have had to get 2 speeds: one at the 2 1/4 trap and
> through
> the full first measured mile. If a vehicle reached top speed and
> slowed
> through the next mile, I used only the top speed and mile marker where
> that
> occurred. I normalized each vehicle to it's top speed. So here is some
>
> preliminary info and maybe the final look also. Not as interesting as
> I
> thought it would be.
>
>   Mile         % of Max Speed     # of Vehicles
> 2.2500             0.9464                      82
> 3.0000             0.9651                      82
> 4.0000             0.9802                      43
> 5.0000            1.0000                       29
>
> That is of the 82 vehicles that surrived the ground rules I set up,
> the
> average spercentage of their individual maximum speeds was 94.64
> percent.
> That is 100% of the 82 vehicles was able to reach an average of 94.64
> % of
> their top speeds. That same 82 vehicles made it to the 3 mile flag
> (naturally, my ground rule!) and they were able to gain speed up to
> 96.51%
> of their top speeds by that point. Now it is interesting that nearly
> one
> half, 39, bailed out between the 3 and 4 mile marker. I do not know
> whether
> or not this was automotive darwinism in action or they were somehow
> licensing runs. But those remaining 43 vehicles gained another few
> percentage points: 98.02% of their top speeds. Again there was a drop
> in the
> number of vehicles running for the 5 mile flag. In this final
> category,
> these vehicles finally reached their top speeds.
>
> What does it all mean? I don't have the foggiest notion. A mental
> exercise
> for me...interesting? I am not sure any longer. Pareto's law was
> ambushed
> because my hypothesis was that 100% of the cars would reach 80% of
> their top
> speed in 20% of the distance. Well, 20% of the distance is mile 1 and
> there
> is no time trap there...so was doomed from the git go.
>
> mayf, the confused, really ignorant, no dumb, desert rat in Pahrump.

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