Hi, John:
sorry to butt in here, but I think you are making an assumption that just
doesn't work.
First of all, it's not intuitively obvious to me that the impact when the
vehicle returns to the salt will be 2g, or even twice the original downforce
(considering aero, also). I think we would need to assume a few angles and
do some calculus and trig to find out what it would actually be.
And-- even if it is always 2g-- does that help? Not unless you already
needed 2g of downforce in order to keep the tires from spinning-- and if
that was the case, you didn't have enough to begin with! In other words--
any downforce you gain from gravitational acceleration is wasted, if you
were well hooked-up in the first place.
There is another "negative" that you get when you crash back to earth: even
though we may only be talking about "washboard" ripples, imagine it
magnified, so the effect is more clear. Your tires "launch" off the peak
of one hill, and crash back into the upslope of the next hill. Where is the
force from the crash absorbed? (Imagine the slope, and the direction of the
tire crashing into it. Maybe draw some arrows.) If you break it into
cartesian coordinates, most of the force is UP-- as you suggest-- loading
the tire. BUT A SMALL FRACTION OF THAT BUMP-FORCE IS TRYING TO HAMMER YOUR
RACER BACK TOWARD THE STARTING LINE.
You probably don't want that.
Russ, #1226B
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net]On Behalf Of John Burk
Sent: Wednesday, October 15, 2003 10:27 PM
To: land-speed@autox.team.net
Subject: Re: suspension/traction question
Hi Dave - There's no question that tires at Bonneville get there share of
air time , less of it with springs pushing them down - My question is , with
the down force always averaging 1 g and unsprung weight being maybe 20% how
much faster is a sprung car - John
----- Original Message -----
From: "Dave Dahlgren" <ddahlgren@snet.net>
To: "John Burk" <joyseydevil@comcast.net>
Cc: <land-speed@autox.team.net>
Sent: Thursday, October 16, 2003 3:08 PM
Subject: Re: suspension/traction question
> If you could yet a track that was perfectly smooth and level and zero wind
along
> with zero slip at any power output then it is a perception.. For anything
else
> it ought to help... A solid suspension has the equivilnet of two kick
balls at
> each end for the suspension. I can roll one down a perfectly smooth road
very
|