You are absolutely right . Opinions vary so much on the items that are
variables it will indeed be quite tough. The front end is easy , it's
getting the back end to work within acceptable perameters. A "fudge" factor
would have to be built in but that may not be acceptable for those out there
. It's going to take at least two or maybe three iterations to get it right
with real world testing .
George in DC
----- Original Message -----
From: Hyatt Engineering Ltd. <Hyatt-Engineering-Ltd@fuse.net>
To: <land-speed@autox.team.net>
Sent: Friday, February 11, 2000 10:09 PM
Subject: Re: Programs to help LSR Racers
> George,
> I am also new to LSR, and building a non-traditional car. With no history
> of empirical data to rely on your program would be a fantastic help. I am
> only an amateur programmer so I stuck with Excel spreadsheets this time.
> However my problem has been excessive discrepancies between the various
> algorithms proposed to calculate the rolling resistance of the tires. At
> high speed the pessimistic algorithms predict more than twice the drag of
> the optimistic algorithms. As I am working on a small streamliner with low
> frontal area, the rolling resistance might contribute to more of the drag
> than the aerodynamics. With uncertain algorithms for the most critical
> component of the drag calculation my Excel program is no better than a
SWAG.
> I would be glad to share what I have done with you, but unless someone out
> there can help us determine which models best represent the unique rolling
> resistance of the salt at high speed, there is not much point in it.
> The two most credible models I have found are from Hoerner and Dayman.
> Which of these two have proven to be the most accurate? Is anyone using
> anything else ?
> Greg
>
> ----- Original Message -----
> From: "George Mitchell" <americanpartner@yahoo.com>
> To: "Jonathan Amo" <webmaster@amoproductions.com>; "Gene Brauninger"
> <genesds@ic.net>
> Cc: "Land Speed Digest" <land-speed@autox.team.net>
> Sent: Friday, February 11, 2000 10:02 AM
> Subject: Programs to help LSR Racers
>
>
> > Skip H and I have been bantering back and fourth about
> > calculatiuons for the design of the (now confirmed )
> > early Hemi powered Porsche 924. We are trying to
> > figure out frontal area and gear ratios . I am trying
> > to get a horsepower figure to shoot for , camshaft
> > design , rpm range etc.
> > Although I can do it with a calculator, Desktop Dyno
> > and just engine design experience I was thinking last
> > night that it would be cool to have a program on my
> > computer that would do these sort of calculations for
> > me .
> > Then I thought " Hey idiot, your a programmer for a
> > living !"
> > I remember seeing a program a few years ago but I
> > don't know if it is available any longer. Besides I
> > have the best resource in the world right here to help
> > design it !
> > Here is what I am thinking would be helpful beside the
> > above mentioned items. I thought it would be nice to :
> >
> > Figure corner weights.
> >
> > With x amount of horsepower and y frontal area on the
> > salt the vehicle should go z MPH --on dirt--on asphalt
> >
> > The record is z MPH ,with y frontal area, how much HP
> > will it take to match or beat it? (reverse of the
> > prior equation)
> >
> > I'm making good hp but x MPH away from the record how
> > will this gear change affect me ?
> >
> > Basically, if you all help me with the specs , I will
> > build it test it and make it available.
> > Any ideas or comments.
> > Would you find something like this helpful ? I think
> > it would help "newbies" like myself.
> > Thanks everyone
> > George in DC
> >
> >
> >
> > Do You Yahoo!?
>
>
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