Mayf:
Right, the fastest machines will probably always have some skips, considering
all
the suspension technology I've heard anything about (unless we can get unsprung
weight down to about 6lb per wheel). But any suspension responds faster than
none, and some suspensions respond faster than others. The faster the
suspension
responds, the shorter the skips. The shorter the skips, the more (net) tire
thrust into the salt.
Russ Mack
DrMayf wrote:
> Inertia...if the vehicle is traveling at any speed then the suspension
> cannot react quick enough to return the wheel/tire assembly to the salt
> after hitting a bump or flying over a hole. Just not quick enough. Will
> always have some skips and of course, wheel spin at those places...
>
> mayf
>
> ----- Original Message -----
> From: "rtmack" <RTMACK@pop3.concentric.net>
> To: "Louise Ann Noeth" <lanoeth@earthlink.net>
> Cc: "Landspeed" <land-speed@autox.team.net>
> Sent: Saturday, December 01, 2001 5:39 PM
> Subject: Re: TC thought
>
> > Geez, Louise, that's the most interesting technical question on the list
> right
> > now!
> >
> > (Our friends in the 77 car being one prominent exception), I think
> suspension in
> > general is way underutilized by cars in the 250mph-plus category. Yeah, I
> know--
> > it's just one more set of variables to have to deal with. But my
> inspection of
> > the course after Speed Week indicated that many of the vehicles were
> loosing
> > traction at the expansion crack "dips", because their wheels were loosing
> contact
> > with the surface. The "starting line" side of the "dip" would show tire
> tracks
> > that appeared to be laboring somewhat successfully-- then there would be a
> few
> > feet where the tracks would dissappear (the tires apparently flying over
> the
> > dip!)-- then they would appear again on the other side of the crack,
> really
> > tearing up the salt (spinning, I feel sure!) It would be nice if we could
> keep
> > the tires in better contact. Suspension is an obvious consideration.
> >
> > As for "active" suspension-- all the reading that I have done on it
> indicates that
> > the purpose is to keep the ride height (distance between the belly and the
> ground)
> > in as narrow a distance range as possible-- and the vehicle level
> (horizontal)
> > from side-to-side. In other words-- a wheel can deflect (or rebound) a
> couple of
> > inches, but the sill & belly remain 1.55" (or whatever) from the ground.
> This is
> > important to the road racers because they use "ground effects"-- the flow
> of air
> > under the car creates a suction that helps them get those incredible
> cornering
> > speeds. And the "ground effects" are extremely sensitive to the height of
> the
> > belly/sill above the racing surface.
> >
> > So my feeling is-- if any LSR builder decides it might be an advantage to
> create
> > (all, or part-of) the tire loading from ground effects, then for sure
> active
> > suspension would be worth a consider. Heck of a development project, I
> would
> > think.
> >
> > I think Pork Pie is over-estimating the magnitude of the problem (caused
> by the
> > "undulations") for TC. Dave Dahlgren and I have both explained ways to
> address
> > that in other responses to this thread. Suspension is, I believe,
> unnecessary for
> > a successfully-functioning LSR TC.
> >
> > Interesting idea, though!
> >
> > Russ Mack
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