Russ,
I'm waiting for someone to make this work on a REAL fast car but I doubt if
I could do it to my liner anyway. One comment, I have driven around a lot of
paved racetracks in my days but none were as rough and bumpy as a good salt
course is.
Howard
----- Original Message -----
From: "rtmack" <RTMACK@pop3.concentric.net>
To: "john backus" <34ford@msn.com>
Cc: "land-speed" <land-speed@autox.team.net>; "kturk" <kturk@ala.net>
Sent: Saturday, October 27, 2001 6:43 PM
Subject: Re: Fw: Rear suspension
> List:
> I hope not everyone is through with this topic-- I've been out of the
country, so
> this is my first opportunity to get in on it.
>
> Like many others have said, "I'm no expert, but..." I went to Bonneville
for the
> first time at Speed Week this year. Had been forewarned that "getting the
power
> to the ground" is the biggest problem for the really powerful cars-- so I
tried to
> observe everything I could about the problem, since I want to build my own
> machines.
>
> One thing I noticed was that some of the fastest cars showed very little
> "roostertail" until they were well past the one-mile-- but by the
"big-end" they
> were really kicking up the salt.
>
> After they had shut-down the course on the last day, I walked out and
studied the
> salt on the long course at about "the three", to see if I could learn any
more
> about those big-end roostertails. I could see distinct tracks from some
of the
> vehicles. I assumed that the deepest and most distinct tracks probably
belonged
> to (drive) tires that were under the most stress-- the cars with so much
power
> that they could barely keep it "hooked-up". I saw a particularly
interesting
> phenomenon repeat itself in several different sets of tracks:
>
> as the track approached an expansion joint, it would suddenly
disappear;
> when it reappeared on the other side of the joint, the tire was
> tearing-up the salt much worse!
>
> I assume this was due to the fact that the tires accellerated during the
time they
> were unloaded, and then they just spun when they re-contacted the salt. I
don't
> know about that "three-foot [wide, I assume] dip" thing that someone
mentioned
> earlier. Didn't have a long straight-edge with me. But I could see that
the
> expansion joints I was looking at did seem to be depressed. However, some
of the
> tire track "jumps" looked longer than three feet-- maybe around SIX feet.
>
> Some very smart and experienced LSR people have told me that they think
the most
> powerful vehicles are probably loosing 15% of their potential tire thrust
to
> "slip". If that is right-- then clearly it can be the difference between
reaching
> your speed goal, or not.
>
> What many people have said about the practical stumbling-blocks-- in
adapting a
> rear suspension and getting it to work-- are all points well-taken. But
the CART
> cars I'm around all still use suspensions, even on the 240mph speedways.
I think
> suspensions can probably be made to work at our LSR speeds, too.
>
> My observations have convinced me that I should begin building my LSR
machines
> WITH suspensions; then-- if I ever get to the point where I have an
engine that
> is really asking a lot of the drive tires-- maybe I will have experience
that will
> give me an advantage.
>
> Russ Mack
>
>
> john backus wrote:
>
> > ----- Original Message -----
> > From: john backus
> > Sent: Wednesday, October 24, 2001 7:53 PM
> > To: kturk; land-speed
> > Subject: Re: Rear suspension
> >
> > Okay, okay, this may sound really stupid but I do have a theory about
this.
> > What if the engine, trans and rear end were mounted on one frame unit,
> > attached at the front of the engine and the body was attached to another
> > length of frame with springs, shocks, etc. between the two frame
sections.
> > Kinda like one long ladder bar, of sorts that hinges at the front of the
motor
> > with all suspended together with coils and shocks between. I know this
is a
> > lot of unsprung weight but it could be managed and even eliminate the
> > driveshaft.
> >
> > ??????????? John Backus
> >
> > ----- Original Message -----
> > From: Keith Turk
> > Sent: Monday, October 22, 2001 7:29 PM
> > To: land-speed@autox.team.net
> > Subject: Rear suspension
> >
> > Okay along the lines of the Trans mounting system.... I wanna do the
rear
> > suspension issues....
> >
> > My thoughts are that a fancy rear suspension to make the car leave the
line
> > is a Moot point at Bonneville... ( may help you at Maxton or El Mirage )
but
> > once the car is through the gears it's settled down and the only real
> > advantage of a suspension at all is to maintain the contact patch with
the
> > ground....over minor bumps...
> >
> > Joe Timney and I have beat this up at length and I have several idea's
on
> > the correct course of action for me.... But I'm curious to hear others
> > thoughts on what they run and WHY?....
> >
> > In other words... what are your theory's..
> >
> > Keith ( Mayf.... what you doing Hiding out... I love your questions...
> > always pointed .... which may not be pleasing to all ... however they
are
> > always honest and well thought out )
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