rec.autos.simulators

Physics

Christer Andersso

Physics

by Christer Andersso » Sat, 20 Jun 1998 04:00:00


> Okay, so lets talk about aerodynamic drag...o^)

I love your attitude, Todd :o), and I'm looking forward to this discussion :o).
I'm having problem stopping myself from starting to guess on this one... I think
the vacuums is the key here, find where the vacuums turn up around the car when
at speed :o).

/Christer

Christer Andersso

Physics

by Christer Andersso » Sat, 20 Jun 1998 04:00:00



> >> Since the tires are narrower, they'll also cool-off faster!!!

> >Because??? The reason for me asking is that I dont understand why they
> >should. The heat doesn't travel very well within ***, so I guess :o)
> most
> >of the heat probably stays close to the contact surface and is cooled down
> by
> >the air flow and pavement. As I said, I dont understand this yet :o).

> You just answered that one yourself Christer..
> Since theres less area or mass to cool-off, the process will go much faster.

Less area is a bad thing if you want to cool something. The worst scenario is a
sphere, cause regarding a sphere you have the worst relation between volume and
surface area. You have to little surface area per volume. In a narrow tyre
compared to a wide tyre this relation isn't very different, it's actually a
little bit worse for the narrower tyre, cause it's closer to the circle shape,
when intersected. What I'm actually is saying is that regarding heat dissipation
through the contact surface, it's about the same no matter how wide or narrow
the tyre is. This is of course on a tyre that is the same in any other way, but
wider or narrower.

/Christer

Bruce Kennewel

Physics

by Bruce Kennewel » Sat, 20 Jun 1998 04:00:00

Heavens!  Surely somebody with the overwhelming facilities of a
tribology lab can keep the power on?!!  Rub a few sticks
together....that produces friction, therefore heat.....doesn't it? :o)


> I had some long explanations typed out and then the power went out. Damn
> Iowa weather. So here is the shorter, sweeter version.

Regards,
Bruce.
----------
The GP Legends Historic Motor Racing Club  is located at:-
http://www.netspeed.com.au/brucek/legends/
Bruce Kennewel

Physics

by Bruce Kennewel » Sat, 20 Jun 1998 04:00:00

This thread is producing some really fascinating stuff!
It's like having a university in my living-room,  available 24 hours a
day!!

Of course, I don't understand a word of it but, Christ Almighty, did I
IMPRESS people at work today!!!  Thanks guys!



> > Todd - I read your reply with interest and I think I understood some of
> > it :) I have a another question though. A friend of mine, who is in
> > science, has stated that the 'force' of friction (if I may call it that)
> > is the same regardless of surface area. That is, if you stood a brick on.....................yada yada yada.

--
Regards,
Bruce.
----------
Bruce Kennewel

Physics

by Bruce Kennewel » Sat, 20 Jun 1998 04:00:00

Of course, if it's raining, they cool off a lot quicker.



> >> Since the tires are narrower, they'll also cool-off faster!!!

> >Because??? The reason for me asking is that I dont understand why they
> >should. The heat doesn't travel very well within ***, so I guess :o)
> most
> >of the heat probably stays close to the contact surface and is cooled down
> by
> >the air flow and pavement. As I said, I dont understand this yet :o).

> You just answered that one yourself Christer..
> Since theres less area or mass to cool-off, the process will go much faster.
> Another issue is the fact that a norrower tire will "flow" way much better
> thru the air, that a wide one - thus getting much more efficient cooling.

> Best,
> Edwin Solheim
> Check out The Paddock -  a legendary site...
> for some cool Grand Prix Legends stuff and tips!
> (http://www.racesimcentral.net/)

--
Regards,
Bruce.
----------
The GP Legends Historic Motor Racing Club  is located at:-
http://www.racesimcentral.net/
Bruce Kennewel

Physics

by Bruce Kennewel » Sat, 20 Jun 1998 04:00:00

No, Christer.
I drag my vaccuum around the house, cleaning behind the sofa like a good
husband, and I have no friction problems at all....it glides along very
smoothly.

I'm starting to understand this stuff, I think :o)!!



> > Okay, so lets talk about aerodynamic drag...o^)

> I love your attitude, Todd :o), and I'm looking forward to this discussion :o).
> I'm having problem stopping myself from starting to guess on this one... I think
> the vacuums is the key here, find where the vacuums turn up around the car when
> at speed :o).

> /Christer

--
Regards,
Bruce.
----------
The GP Legends Historic Motor Racing Club  is located at:-
http://www.netspeed.com.au/brucek/legends/
james crocke

Physics

by james crocke » Sat, 20 Jun 1998 04:00:00

I'm not sure what you mean by "flow", but turbulent air flow will cool the
tire more quickly than laminar (smooth) flow.  Also, I may be
misinterpreting what you said, but for a given mass of *** the one with
more surface area will cool faster.

Jerry Logsd

Physics

by Jerry Logsd » Sat, 20 Jun 1998 04:00:00

You're right, the molecules don't know what's goin on more than a couple
microns away. Let me try to explain. If one square cm has 100 bonds, then
ten sq cm will have 1000 bonds. Each individual bond adds to traction and
the number of bonds is dependent on the surface area of the contact patch.
So bigger tires have more bonds and therefor more traction. Got it?

- Show quoted text -

You're right, I didn't realize you were not from around here. I knew an
exchange student from Sweden. Her name was Asa and she was the best
looking girl I've seen in awhile.

- Show quoted text -

No, same number of bonds per unit area. More area then equals more bonds.

- Show quoted text -

Pedagogic huh? I know you're foreign now. No native english speaker would
ever use a big word like that.

Jer

Jerry Logsd

Physics

by Jerry Logsd » Sat, 20 Jun 1998 04:00:00

> Of course, if it's raining, they cool off a lot quicker.



> > >> Since the tires are narrower, they'll also cool-off faster!!!

> > >Because??? The reason for me asking is that I dont understand why they
> > >should. The heat doesn't travel very well within ***, so I guess :o)
> > most
> > >of the heat probably stays close to the contact surface and is cooled down
> > by
> > >the air flow and pavement. As I said, I dont understand this yet :o).

> > You just answered that one yourself Christer..
> > Since theres less area or mass to cool-off, the process will go much faster.
> > Another issue is the fact that a norrower tire will "flow" way much better
> > thru the air, that a wide one - thus getting much more efficient cooling.

I think the main way heat is removed from the tire is thru contact with
the pavement. The air flow might play a role in open wheel cars, but even
then I believe the car designers try to direct the air flow over the
tires. The top of the tire is moving against the air flow and really
disrupts things.

A couple thoughts on heat traveling thru the ***. First, I think that
the whole tire should be pretty uniform in temperature because there is no
localized  heating. Second, do race tires use steel belts? My guess is
they don't but I'm not sure. But if they do, then the steel would conduct
the heat pretty well.

Jer

Remco Moe

Physics

by Remco Moe » Sat, 20 Jun 1998 04:00:00


>>Since theres less area or mass to cool-off, the process will go much
>faster.
>>Another issue is the fact that a norrower tire will "flow" way much better
>>thru the air, that a wide one - thus getting much more efficient cooling.

>I'm not sure what you mean by "flow", but turbulent air flow will cool the
>tire more quickly than laminar (smooth) flow.  Also, I may be
>misinterpreting what you said, but for a given mass of *** the one with
>more surface area will cool faster.

That should be: more surface at a given volume. Smaller tyres will
have relative more surface.

Remco

Matthew V. Jessic

Physics

by Matthew V. Jessic » Sat, 20 Jun 1998 04:00:00


> No, Christer.
> I drag my vaccuum around the house, cleaning behind the sofa like a good
> husband, and I have no friction problems at all....it glides along very
> smoothly.

> I'm starting to understand this stuff, I think :o)!!

What ever you do, DON'T vacuum in the garage when the car is
on the road. (If you have a spoiler, the sudden loss of
downforce from disrupting the starting vortex could lead
to a *** accident.)

;)

- Matt

Christer Andersso

Physics

by Christer Andersso » Sun, 21 Jun 1998 04:00:00

Made me laugh out loud on that one, Bruce, thanks :o))).

/Christer


> Of course, I don't understand a word of it but, Christ Almighty, did I
> IMPRESS people at work today!!!  Thanks guys!

> --
> Regards,
> Bruce.
> ----------

Christer Andersso

Physics

by Christer Andersso » Sun, 21 Jun 1998 04:00:00


> You're right, the molecules don't know what's goin on more than a couple
> microns away. Let me try to explain. If one square cm has 100 bonds, then
> ten sq cm will have 1000 bonds. Each individual bond adds to traction and
> the number of bonds is dependent on the surface area of the contact patch.
> So bigger tires have more bonds and therefor more traction. Got it?

:o))) Well, actually... no :o). Bare with me will you, please. If we have a tyre
with a contact patch of one square cm and it has 100 bonds, then the pressure on one
bond will be 1/100 of the pressure, right? If we increase the contact patch to ten
square cm, it will have 1000 bonds. The pressure per bond will now only be 1/1000 of
the pressure, or 1/10 of what it was on the smaller tyre, but you say the traction
added from a bond will not have decreased with 1/10, but with less than 1/10, on the
bigger tyre... Why? Not why you say it, but what causes it :o)?

Well, it's my wife, and she doesn't remember you, but stay away anyhow :o).

Then the traction from the bonds cant be proportional to the pressure. It seems as
if the bonds get stickier the lower the pressure is???

/Christer, dont understand the magic bonds :o(

Bruce Kennewel

Physics

by Bruce Kennewel » Mon, 22 Jun 1998 04:00:00

:o)
Ur welkm!


> Made me laugh out loud on that one, Bruce, thanks :o))).

> /Christer


> > Of course, I don't understand a word of it but, Christ Almighty, did I
> > IMPRESS people at work today!!!  Thanks guys!

> > --
> > Regards,
> > Bruce.
> > ----------

--
Regards,
Bruce.
----------
The GP Legends Historic Motor Racing Club  is located at:-
http://www.netspeed.com.au/brucek/legends/

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