Dave & mayf;
Let me propose a slight addition to your "salt hardness test". In addition
to "...dropping a sphere of a known weight and height and checking the depth
of the depression..." it would be useful to also measure the height that
that sphere rebounds to. This will add a data point that measures the
coefficient of restitution-- how much energy is lost by that deformation and
springback. My guess is that the higher the coefficient is, the less power
is required to make that "rolling dent" in the salt surface. Sort of like
the difference in a train wheel rolling on a steel rail and rolling in sand.
Regards, Neil Tucson, AZ
-----Original Message-----
From: Dave Dahlgren [mailto:ddahlgren@snet.net]
Sent: Wednesday, August 13, 2003 7:32 AM
To: DrMayf
Cc: land-speed@autox.team.net
Subject: Re: Bonneville Request
they post it right on the fuel truck for every one to see and i believe they
update it hourly.. You might ask them when they update and conduct your
tests right around the same time as well. I would be the most interested in
the moisture content and hardness of the salt as i think that has the
biggest effects on speed but may or may not effect traction that much. If
the surface deforms it has to absorb power in doing so. In essence you are
continually driving up hill out of the hole. I vote for a test, if I get a
vote LOL as it is your project maybe suggest is a better word, that
involves dropping a sphere of a known weight and height and checking the
depth of the depression along with the salt temp and moisture content.. it
would end up being sort of a 'hardness test'... You could have your own
Mayfield salt hardness test like that Rockwell and brinnel scale.. End up
with a number like 22 MayfSH with the numeric part the depth of the
depression or the combination of deep and water content.... Dave
DrMayf wrote:
>
> That would be cool. Now all I gotta do is ask them to let me have
> access to the data. Aren't they outside the pits also? That would/will
> work. I can spectate from around there and then at each measurement go
> and get the data. My plaan in all of this is to not only measure the
> friction coefficient ewach hour or so during the day but to watch how
> the water in the salt rises. This should be apparent in the CoF data.
> I can plot vs temp or/and pressure and or air density. When done, I
> will provide data to anyone who wants the data and will post on my web
> site after I return home.
>
> mayf
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive
|