From: ecrjbruce@economics.adelaide.edu.au
Newsgroups: rec.autos.sport
Subject: Re: When you're wrong, you're wrong. (was Re: ABS ???????)
Date: 9 Nov 92 09:23:54 GMT
Organization: Economics, University of Adelaide
NNTP-Posting-Host: eco.economics.adelaide.edu.au

>>OK Matt, we've been having a discussion inprivate email about ABS etc and
>>physics and how you see the world view.
> 	     ^^^^^^^^^^^^^^^^^^^^^^^^^^
> What the hell????

What the hell precisely.  You even took the trouble to underline the part that
offended you.  Now go back and read your own posts and you'll find that line
comes from something you wrote.

> 
> 
> O.K. Rob... That's it. I've had it with you. I tried to keep things civil and in 
> private email,

Agreed.  Public flames become boring very quickly, as we'll no doubt soon
discover.

> even though your ignorance of some basic facts, and your insistence
> of your correctness nonetheless, has been infuriating.

And I guess you claim to be infallible.  We shall see.


> I'm glad you decided to spill
> things over onto the net, because now comes the real hammering:

Maybe.

> 
> Since the posting of excerpts from private email is considered so utterly tasteless,
> I will paraphrase your ridiculous drivel, but if you so much as insinuate what I've
> paraphrased is NOT what you claimed, I will post verbatim your incriminating, 
> misguided nonsense for everyone to see.

And now we see the real you.  You seem to be able to flame away at other people
but when one of your own lines is thrown at you you get upset.

More on my "ridiculous drivel" later.

If you choose to post everything to the net I have no complaints.  I just ask
you to post it all in one lot, since I don't appreciate it when other people do
this sort of thing and I guess most other people don't give a rats about this
one.

> 
> You insist (a number of times) even after being given the chance to reconsider,that:
> 
> *Static friction occurs when a wheel has locked up (and hence is static, ha!) and 
> slides along the tarmac. And you've read this in physics texts.* 

Not quite.  Go back and read what I said (and post it if you like).  Given I
have only got 1000 blocks of quota I can't keep all our postings and thus I am
unable to do it myself.  
                              
Not only have I read my info in 2 texts, it's backed up by a group of friends.
That may not mean much to you except that one is doing a PhD in Physics, 
another in Maths Sciences, the third in Engineering and the fourth is a 
qualified engineer who goes racing.  The other sources I referred to are a CAMS
(confederation of Aust. Motorsport) handbook for drivers and my lecture
material from an advanced driving course I did about 2 years ago.

> 
> Well I don't know what kind of physics they teach in Oz.
> 
> You also insist that dynamic friction occurs when the wheel is rolling freely. 
> (dynamically I guess!) 

Thats what I have been told.  Thats what is in various handbooks.  As for being
read in texts that refers to the fact that dynamic friction takes much greater
force to break traction than static.

> 
> And that *I* am the one who doesn't understand the difference between the two. 
> Oh that's rich. What incredible arrogance.

Almost as arrogant as your "world view"  posting that prompted the one in which
you vented your spleen.

If you don't believe me read item 15423 in this group.

"wrong yet again"
"the decent drivers outperformed the ABS systems in *all* conditions including
dry tarmac"
"OK? This is fact. Sorry it contradicts your world-view"

The above are quotes from that particular item.  It's there for all to see so
go check it.

You claim that I fail to understand basics yet you claim that the greatest
advantage ABS has is on dry tarmac - which is precisely ABS has it's LEAST
advantage over a human driver.  ABS excels in difficult conditions, the gap is
much closer in good conditions.  To me that's a basic principle of ABS.  Of
course you no doubt think I am wrong again.

> 
> As if that isn't enough, you then fail to grasp the concept that the point at 
> which a tire breaks traction with the asphalt is NOT the same as the point at 
> which the rotor and pads bind together, and that this is the whole concept of
> threshold braking, to keep the wheels slowly turning. You dismiss this as 
> nonsense despite the fact that I cited sources, including Alain Prost's 
> Competition Driving,  in which he discusses this concept, and even has a 
> photograph of a car threshold braking. I, and others at the track, do what you 
> say doesn't happen, routinely.

Um where did I say this??  I suggest you go back and read my posts.  I have
ALWAYS referred to the situation where the tyre has stopped turning.  After all
if the tyre is still turning then this is exactly the situation ABS is trying
to create!  Also you have cited a source, not sources.  I have no argument that
the greatest braking occurs when the tyres are still turning slowly, I disputed
that the greatest braking occurs when the tyre is locked.  I also said you have
no control once the front wheels are locked.  I NEVER said you do not get
maximum braking when the tyres are still turning slowly, because that is what I
have been arguing all along.  This is the situation ABS tries to create
wherever possible.  
  
> 
> 
> O.K. Next.
> 
>>In one of your posts you claimed that the best starts are those with a tyre
>>slip of about 12%, because this gets the most power to the ground.  This seemed
>>absurd to me and I did some checking. 
> 
> Well for someone who doesn't believe that a tire slides in threshold braking, 
> I guess it would!

OK in exact THEORETICAL threshold braking a tyre doesn't slip.  However given
none of us are good enough to be right on the very edge of the envelope, in 
PRACTICE threshold braking takes us that little bit past the ideal theoretical
threshold because that is the only way we can be sure that we are as close to
the threshold as possible.

> 
> 
>> In fact I didn't have to go very far
>>because we have our F1 Grand Prix right here in little ol' Adelaide this
>>weekend, and naturallt [sic] the papers are covering it pretty intensely.
> 
> Oh Now there you have it! Talk about backing your arguments. Wow you just can't get
> any more authoritative than the local newspaper! Give me a break!

Oh dear.  Tell that to Woodward and Bernstein!  When the papers are covering a
F1 GP and they quote Patrick Head I generally assume they are a somewhat
authoritative source.  Why trust Prosts book more??  If Prost is such a great
theoretical physicist and designer why do teams employ designers?  Why not have
your driver do that as well if he's the most authoritative source on all things
technical?  BTW "The Advertiser" is the equivalent of the "Times" or whatever
your reputable major dailies happen to be.

>> 
>> Williams claim that one of their major
>>improvements will be a "traction control" which will limit slip at the start to
>>a "fraction og [sic] 1 percent".
> 
> Now, this, in all honesty, I don't know what to make of. Unlike you, I can certainly
> admit that I may not understand the entirety of a situation.

Um like when have I ever claimed to understand the whole situation?  If you can
show me that I'm wrong then I'lllisten.  However at the moment you have what
you say and Prosts book to quote from, whilst I have checked out 2 text books
I still own, my notes about advanced driving (note that I don't claim to be an 
expert driver, just someone who enjoys driving and takes it somewhat seriously)
,and several PhD and other qualified types.  You tell me where you feel the 
greater use of authoritative sources comes from.  If you can show me how to 
improve my lap times I'll be grateful, but currently the evidence is against
you.



> It seems odd to me.
> If it is true then I will have to examine the circumstance in which it is true 
> further. Perhaps the newspaper reporter got it wrong and the original Williams 
> statement was that wheel spin could be *controlled* to within 1% ??? 

So now you claim the reporter got it wrong?  Very interesting.

> No but that couldn't possibly be now could it? No way. Uh uh. 

Why couldn't it be controlled like that??  I don't know, I guess that's why
Williams are spending considerable time and effort to do it.

> Ever see a dragster launch without wheel spin? I haven't.

Neither have I.  But I do know that they run their tyres at about 13 psi to get
more traction.  Also a dragster is a relatively unsophisticated vehicle.  Its a
huge engine in a lightweight body designed for minimum time over 1/4 mile. 
This doesn't neccesarily mean fastest speed, if it takes too long to get to
60mph and then quickly winds up to 200mph that MAY not be as good as a design
that rapidly gets to 150mph and then takes a fraction longer to get to 200. 
Note the use of the word MAY, it's very crucial in that sentence.

> If the optimum percentage 
> of slip is less than 10% I wouldn't be terribly surprised. 
>But it sure isn't zero.

Why not? (genuine question).  It would seem that if you get all your power to
the ground there is no wastage so you not only get greater acceleration but you
also save your tyres from damage such as potential (note the word potential)
blistering and excessive wear.  I'll have to check this out  :)
 
 
>>Guess this contradicts your "world view" and that
>>theory of yours.  Now if you cantell me Williams are going to spend millions
>>developing products to make their car less efficient at the start then I may
>>believe you, but given your taste for making statements backed up with
>>absolutly no facts I guess this also throws your somewhat questionable ABS
>>psoting into doubt as well.
> 
> You know...Rob. I have been on this net for a few years now, and I've never had
> a situation like this where someone was so utterly wrong, and so clearly in need
> of a better understanding of things, and yet so insistent of his correctness.

Well as I have said, from the way I see it the evidence is stacked against your
argument.  You may disagree (that's your right after all) but I have
several opinions and several sources which disagree with you.  On probability I
would say that suggests I am more likely to be correct.  Again I say to you,
show me where I am wrong and provide substantial evidence to prove it.  I have
my opinions and have checked them reasonably well (I can't be bothered to get
more opinions to be honest) but if you can show me exactly how I am wrong then
let me know.
> 
> Wise up guy. Learn the difference between static and dynamic friction and that
> you can have both at the same time with a tire before going around telling other 
> people they don't understand it.

Sure you can have both at the same time - in PRACTICE.  Read what I sent to you
about rally turns etc.  Maybe you didn't interpret it quite properly.

> 
> Now do us all a favor and go do your homework.

I seem to have done more than you.  Give me some reason to believe your
homework is better than mine and I'll agree, until then I'll stick to my
opinion.

> And I don't care if you've driven 
> vees and karts or whatever else, when you're wrong you're wrong.

Agreed, it's just that I happen to feel I'm right and believe that the evidence
I have backs me up.

> As said and written many times before, simple ABS alternates between 0% and 100%
> slip, and human drivers can keep the slip at a steady 10% or so. Apparently you
> don't even acknowledge the need to do so for optimum braking!
>
Maybe we had better define slip, that may be the root of all the hassles.  As
for human drivers being able to maintain perfect human braking and 10% slip etc
then tell that to Gerhard Berger.  I was sitting at the end of the main
straight and he didn't seem to do it 100% of the time.  Situations like that
are where ABS (or EBS - see my post to you about susension being an important
parameter) come in really handy, they save your tyres from damage (flatspots)
and give you a greater margin of error with regard to control etc.

** Are you defining slip as the slip between pads and rotor??  If so we may 
have a cause of the problem here, we talk about slip as being between the tyre
and the surface.  If you are working on the former defn than it would explain
much. Sorry I didn't mention it earlier it only just occurred to me that we may
have had problems with definitions of this sort **


> If I were you, I wouldn't dig myself a deeper hole, or I'll go back and get every
> one of your ABS postings (gems of information that they are), and every one of the
> emails you sent me and take them apart each line by misinformed line.
> 

Go for it if that's your desire.  I don't consider my postings misinformed and
will happily explain them.  This would be time consuming and tedious but as
long as you keep it in one article so that others can skip iteasily if they
wish then that's no skin of my nose.


Why are you so upset?  I posted back to news simply because you flamed a guy
(IMHO) with your "world view" comments.  So I wrote back a reply using exactly
the same line and the style that you employed and you get upset.  Perhaps you
better consider the other persons perspective when replying, it certainly upset
you when I used your tactics against you.  

Now all I have to do is throw in lines like "go do your homework", "wise up
guy", "gems of misinformation that they are", "If I were you I wouldn't dig
myself into a deeper hole", "and I don't care.... when you're wrong you're
wrong", "and I've never seen a situation where someone was so utterly wrong.."
and I'll have matched you for insults.  But that isn't my style.

Rob