I would think there ought to be a way to measure moisture content
electronically. Similar to a dielectric test i would think. How do they do it
with wood i don't think they weight them and burn them do they?? Plus i don't
want to do an excavating job to get the measurement or take hours to do it.
I would use it to compare to either wheel slip or accelerometer readings. See if
there is a correlation to it all. or to see if it really changes very much at
all during the day. If it does not change then the experiment proved that
whatever it is that changes the times in the am for many cars is not the salt.
personally I think there s a lot to it but it will remain to be seen.
I know I have heard a lot about good and bad salt conditions, i would just like
to quantify them and relate those conditions to the performance of a car or
motorcycle. What may be good for one type car may be bad for another.
Dave Dahlgren
rtmack wrote:
>
> Dave, all:
> A large part of my career has been spent in developing test methodology. Your
> traction & hardness tests sound appropriate. The friction coefficient of the
>rubber
> and the weight and size of the ball would need to be standardized.
>
> For moisture content: carefully measure a volume of salt from the surface.
>Weigh
> it. Bake it for several hours (over 212F). Weigh it again.
>
> How can we objectively compare this data to results of the speed runs? (since
>there
> are so many other factors involved)
>
> Also, someone would need to maintain and update the database.
>
> Russ Mack
>
> Dave Dahlgren wrote:
>
> > It has seemed to me that most every car i have worked on went slower in the
> > morning return run than they qualified and to go with that most went faster
>in
> > the late afternoon return runs when they had them. The cars all seemed to
>not
> > hook up as well as they did during the day. Possibly the salt is slightly
>wetter
> > or drier, or maybe softer or harder. All I have noted is the traction seems
> > worse in the morning than afternoon. Seems like it is worth a further look
> > though. The one thing i have also noted in the last 10 years all or most of
>the
> > larger streamliners run in the mid to late afternoon. They are the most
>traction
> > limited cars out there in my mind. Ok Mayf how do we easily measure the
> > available traction and hardness. I have 2 ideas. For traction a small
>weighted
> > sled with rubber on the bottom and a pull scale. measure the breakaway and
> > sustaining force to move it along the salt. Then a round metal ball may a
>few
> > pounds in weight dropped from a certain height and measure the diameter of
>the
> > imprint to measure hardness.. Could also measure the temperature and I am
>sure
> > someone would have a way to measure the moisture content at the surface.
>With
> > all the traction issues at Bonneville it really has to come down to where
>the
> > rubber meets the road for a lot of people. It has always made me a big fan
>of
> > slippery light cars that do not have traction issues in the first place.
> > Dave Dahlgren
> >
> > Marge and/or Dave Thomssen wrote:
> > >
> > > The Hayseed's two-bits worth:
> > >
> > > Aero drag and horsepower produced by a gas aspirated engine vary exactly
>the
> > > same with change of air density. At zero density aero drag is zero and HP
> > > is zero. rolling resistance is not affected by air density, so the cars
> > > (such as streamliners) that have the greater part of their resistance
> > > brought on by rolling resistance will suffer the worst when air density is
> > > lowest. If aero drag is lower and HP is lower, rolling resistance is
>still
> > > high, so a streamliner benefits from high barometer and low temperature.
> > > Obviously the engines with oxygen-bearing fuels will not be affected as
> > > much.
> > >
> > > Dave D is quite right when he said that high speeds produce lots of
> > > rolling resistance. The SAE paper describing the goldenrod calculated
> > > higher rolling resistance than aero resistance at 400 MPH. All this stuff
> > > depends on what kind of car you run. When I run a fendered street
>roadster
> > > the aero drag is so monstous that rolling resistance is comparatively
>small,
> > > so in goes the ballast.
> > >
> > > As to dry vs. wet salt: do we know for sure that speeds are slower in the
> > > morning? If they are, could it be because the running gear (rear end,
>wheel
> > > bearings, trans, etc.) are not yet warmed up as much as when you run in
>the
> > > afternoon heat? It does seem to be a fact that the salt is wetter in the
> > > heat of the day and capillary moisture comes to the surface and brings
>some
> > > salt with it. Sit still some day and watch the ground and you can see it.
> > > When you get as old as I am you sit a lot.
> > >
> > > Dave the hayseed
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