Yes, the salt changes all the time. Is it predictable? Maybe, maybe not. I
have not worked on the little bit of data I took when there. BUt the general
observation was that the COF was high in the morning decreased towards noon
then went back up again then back down in the latter part of the day. There
are some theroies around which may account for a lot of variability on the
when of changes due to water infiltration, but not yet ready to stick my
neck out. I would say that yes, 10 mph wind would have some drying effect on
the salt, hence some cof changes.
We had all chatted some about slippage and the conclusion is that up to 20%
slip is best for maximum acceleration. However you reach a point where
engine torque cannot overclome the slip and the grip starts to move back
towards the static limit of adhesion (cof). You can also run up against aero
and mechanical drag elements which will allow the car to go no faster and
makes the tires spin (which means more weight or down force is needed).
I'll have some additional comments and thoughts a bit later. I am trying to
get my shop sorted out again. I bought a maple laminated top work bench, a
steel work table, and a small steel table which is going to be a welding
table. I am building a "pipe stowage rack, for miscelanneous metal bts and
pieces I have.
Will work on salt ideas next week..
mayf
----- Original Message -----
From: "Bryan Savage" <basavage@earthlink.net>
To: "DrMayf" <drmayf@teknett.com>
Cc: <land-speed@autox.team.net>
Sent: Saturday, August 23, 2003 11:38 AM
Subject: Re: hardness/Cof salt test
>
> Mayf,
>
> I've heard for 30 years the statement: "The salt changes all the time"
> I don't remember anyone explaining exactly why and almost without
> exception the change is for the worse during a single day.
> I would sure like to know why.
> Has anyone drilled a hole and tracked the subsurface water level
> during a day? If so has that been related to ambient conditions?
> If the wind blows over 10 MPH does this change the traction?
> How much? How long does the wind need to blow to make a difference?
> What set of conditions produce optimum traction?
> Getting bite on the salt becomes the number one problem when a
> fast car is sorted out. More information about the behavior of the salt
> would be useful to a lot of people based on what I saw last week.
>
> I suspect you will come up with more questions than answers at first Mayf.
>
> Thanks for trying to help ALL of us,
> Bryan
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