Hello, I downloaded this setups file from the wuarchive ftp site but some
of the setups in the file have not really helped me. I felt the car handling
to be quite bad in Estoril and Spa. Also I was generating speeds of around
196mph at Hockenheim whereas some of the computer controlled cars were
zooming past me at 207mph. Are there any good setups anyone can offer me
for the various tracks. Also can anyone tell me what is going wrong with
the setups and why I am not able to get higher speeds and better car
handling with those setups. I have a WCeditor 2.0 edited names 94 file
and was driving a Benneton with 735 power setting. It would really help
me a lot if someone could give me the good setups.
Thanks in advance for all the help.
Anand.
Notable threadF1GP car setups and a long brake-bias physics debate
A player complained that downloaded F1GP setups did not suit him, and others advised building a setup around personal preferences. The discussion turned into a lengthy physics argument about brake bias, weight transfer, downforce versus weight and centre of pressure, citing Carroll Smith's 'Tune to Win'. Gordon Bell posted the F1GP/World Circuit FAQ v1.01, and a short meta-debate followed about whether vehicle-dynamics talk belonged in the group, with some arguing it was relevant to judging simulator realism.
Automated summary.
The "good" setups you downloaded were someone's opinion, not the
absolute best that can be attained. Also, I think most people will tune
their cars differently according to what they like. How much understeer do
you like? Oversteer? Do you prefer a good top end or grip in the corners?
My method for setting up is to carefully study the manual and
first find the fastest speed they mention for that track. Then I set the
wings to match that. Takes some patience. Then you fix the gearing to make
sure that it matches your top speed. Then if you still have the patience
left you experiment with the brake balance. Turns out that it works better
when set to rear even though that's unrealistic. Some bug I guess.
--
Max Behara
Molly: "DS+MC" Bt+W C 1.2 X+++ L W C+++ I+++ T+ H+ S++ V+ P-
"The Net interprets censorship as damage and routes around it." - John Gilmore
- Have modem, will surf. -
I find it to be quite realistic. From what I know, if a car (with front
brakes stronger than rear brakes) is under heavy breaking then the front
wheels will be getting harder to control. It also affects line stability
as the rear of the car pushing in front. Whereas a car with brakes biased
to the rear, you will get somekind of oversteer when braking into corner.
Anyway I'd like to know others setup on the brake. In Hockenheim I set the
brake 18 towards the rear, I find it suits me the best.
Heru
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: >wings to match that. Takes some patience. Then you fix the gearing to make
: >sure that it matches your top speed. Then if you still have the patience
: >left you experiment with the brake balance. Turns out that it works better
: >when set to rear even though that's unrealistic. Some bug I guess.
: I find it to be quite realistic. From what I know, if a car (with front
: brakes stronger than rear brakes) is under heavy breaking then the front
: wheels will be getting harder to control. It also affects line stability
: as the rear of the car pushing in front. Whereas a car with brakes biased
: to the rear, you will get somekind of oversteer when braking into corner.
: Anyway I'd like to know others setup on the brake. In Hockenheim I set the
: brake 18 towards the rear, I find it suits me the best.
While I'm no physics expert, I think it is unrealistic. On first
observation your explanation seemed correct to me as well. But if you
consider a car with even bias...that is, equal braking power on the
front and rear, when the car starts braking, the weight is transfered
over the front wheels which gives them more grip than the rear. So
with the same braking power at the front and rear, the rear should
lock first since there is less weight over them and hence less grip.
So the logical thing to do is reduce the braking power over the rear
tires so that they take longer to lock (hence the forward bias). To
get the shortest stopping distance, you want all 4 wheels to approach
locking at the same time, so you would have to reduce the braking
power at the rear so that they didn't lock before the front. It
doesn't seem to work this way with WC, in fact it seems to act in
reverse. One thing I'm still not sure of is the effect of the rear
wing. I think the rear wing on an F1 car produces more downforce than
the wing on the front, so at full speed, there is probably more weight
on the rear. I wonder if all that extra weight is taken off under
braking from a high speed. It could be that under braking, there is
still more weight over the rear than the front..in this case the sim
would be correct.
I am driving without Steering assistance and I use a brake bias
setting of around 4 or 5 to the rear at most tracks..
Hope this isn't as confusing sounding when you read it as when I wrote
it..<gg>
RQ
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>While I'm no physics expert, I think it is unrealistic. On first
>observation your explanation seemed correct to me as well. But if you
>consider a car with even bias...that is, equal braking power on the
>front and rear, when the car starts braking, the weight is transfered
>over the front wheels which gives them more grip than the rear. So
I don't think the weight transfer adds much grip on the front wheel since
it is not a vertical downforce. A bit off the line, this weight transfer
is very undesirable in motorcycle since it loads up the front wheel thus
using up the available traction. I think you can imagine what will happen\
if the front wheel running out of traction. 8-O
>reverse. One thing I'm still not sure of is the effect of the rear
The rear wing certainly does have effects on braking. At high speed the
wing produces a lot of downforce which generate high level of traction.\
This will prevent lock-up until the braking force exceed the available
traction. That's why I think the sim is quite correct.
Heru.
>I am driving without Steering assistance and I use a brake bias
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# Heru A Hariati # Psychoanalysis makes quite simple #
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>I don't think the weight transfer adds much grip on the front wheel since
>it is not a vertical downforce. A bit off the line, this weight transfer
Excuse me, but I must have been really dumb in physics class. Weight is
generally
a vertical downforce... correct me if I am wrong about the location of
the
center of the planet....
I think there are a few things that people are not seeing in the braking
that can be exemplified by Pual Tracy's run at Longbeach which most likely
cost him the race.
First, the car's brake bias given that all other features are
constant(tire condition,and fuel load okay not in f1gp) will cause the car
to loose traction under braking as the bias is moved towards the rear of
the car. We all saw, hopefully as Tracy entered the right hander at LB
how he had that spin. Now this shows that there was too much break in
the rear of the car given that chassis setup. I see the point that on
f1gp the bias can be run to the rear. This, however does not take away
from the same Idea that Can be see in Tracy's spin. F1 cars produce much
better traction and downdforc then indycars due to weight ect. To add to
that Micheal said that in his F1 car he could break much later for a
corner then in an indycar due to the weight. This Late braking leads me
to believe that F1 cars can run the break bias more towards the rear then
one would think.
Now, In the Sim I have just gotten done trying to break hard and have my
bias set around 5 rear where I usuall run 1 or two. I must say that the
car tended to have less controled steering or It broke loose quickly
This in my mind shows that the sim is right in the bias settings.
Matt
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: This Late braking leads me
: to believe that F1 cars can run the break bias more towards the rear then
: one would think.
I agree that they can brake much faster than Indycars (due also in
great part to their carbon discs all the way round as well as lighter
weight and better grip). Interestingly enough, I picked up the May
copy of Automobile magazine today and it has a decent article where
Derek Daly tries both last years Williams and last years Newman Haas
Lola Indycar. The performance difference is not as great as you'd
first think.. But he did mention how much stronger under braking the
F1 car is compared to F1 cars 10 yrs ago.. The maximum lateral grip
figures only differ by 0.5g (the Indycar at 4.0 and the F1 car at
4.5g). And this is the 'active' Williams.. Acceleration times
(0-60)differ by only 0.1sec (IndyCar 3.0s/F1 car 2.9s). And 1/4 mi
to carried out on the track I guess..
: Now, In the Sim I have just gotten done trying to break hard and have my
: bias set around 5 rear where I usuall run 1 or two. I must say that the
: car tended to have less controled steering or It broke loose quickly
This is opposite to what I've heard from many people.. I will try the
same type of test and see.. You could be right..
RQ
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M Y O P I N I O N S A R E E X A C T L Y T H A T
Sorry for the delay, but here is the FAQ as it currently stands.
MICROPROSE F1GP/World Circuit - FAQ
VERSION 1.01
COMPILED BY Gordon Bell ([email hidden])
LAST UPDATED - 1st March 1994
Introduction
============
This is the FAQ for Microprosess Grand Prix racing simulator known as either
"Formula One Grand Prix" or "World Circuit". I have only played the PC version
of the game, so this FAQ will be about this version, but most of the details
will apply to the Amiga/ST versions too. This document will be posted
regularly and on request to the group Rec.Autos.Simulators on the Internet.
Contributions are encouraged and feel free to point out flaws and add new
information as you receive it. Any information that is particular to the PC
version will be marked with two asterixs (**) to help cut down on confusion.
1 What is F1GP?
===============
F1GP is Microproses' first attempt at a car racing simulator and is
based around the high-speed world of Formula One races. You take the place
of a driver and compete at all 16 races in the 1991 series, with results
counting towards both the drivers and constructors championships. The game
features practice and qualifying at all events and you are pitted against
33 other drivers. It is one of the few proper racing simulators to use
polygon based graphics, Indy 500, being the only other major one at the time
of its release.
** Possibly Mario Andrettis used polygons???? **
1.1 What system does it require?
--------------------------------
According to Microprose the game runs on a 286 or higher with at least
1mb of RAM. Of this you require 600k base memory. The game should be installed
on Hard Disc, and it takes up 6mb with all animations, 3.2mb without intro
animations, and 2mb without any animations. This CAN be cut down further if
you delete a few of the .DAT files! (I have managed to get the game onto 1 360k
disk, although with only one course). The only other requirement for the game
is a VGA/MCGA graphics card. Mouse and joystick are both optional.
The Atari ST version comes on 4 double density disks, and the first can be
skipped on start up.
** Could someone mail the Amiga and ST details and I will include them **
1.2 ** What sort of performance can I expect?
-----------------------------------------
Here is a rough table of machine against performance, the
Machine Memory Detail Process Speed
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
486dx266 8mb 4d T 70% 25fps
486dx266 4mb 4d T 60% 25fps
486sx33 4mb 4d NT 66% 25fps
486sx25 4mb 4d NT 100% 25fps (A DELL machine)
486sx25 2mb 4d NT 100% 21fps
386dx40 4mb 4d NT 100% 20fps
386dx40 2mb 4d NT 100% 20fps
The details level is shown by the amount of detail around the track,
1d being the lowest level and 4d the highest, the other detail option is the
track shading, this is shown by T (track shading on), NT (no track shading).
The process column show the average processor occupancy as you go around ANY
track. This is just a rough estimate, but really shouldn't go above 100% very
much. The final column show the speed in Frames Per Second that this set-up
allows.
Curiousley, there seems a slight variation between different machines, even if
they are the same speed, suggesting that graphics card performance MAY have
something to do with it. The only other possibilty is processor cache and
external cache, since these are not listed in the table.
The general consensous seem to be that people would rather have it running
smoother, but with less detail, this shows one of the main advantages of F1GP
over Indycar, in that it runs quickly on a slow machine and smooth graphics
are possible quite easily.
** Does the performance vary on an ST or Amiga? Mail me if it does **
1.3 What versions are available
-------------------------------
The game was first released on the Amiga and ST with the PC version
following around a year later. The Amiga and ST versions can both be run of
disk and do not need Hard Drive installation.
As far as I know there are two version of the game for the PC, F1GP on
floppies, which is supplied on 4 high density disks with optional upgrade
disks, and F1GP on CD, which is EXACTLY the same game but on a silver disk.
Do not buy this unless you don't have a floppy drive, since it costs more and
has NO extra features. Quite what Microprose is playing at is unknown, but
the CD version represents BAD value for your money.
2 ** What support programs are available?
=========================================
Like most modern games there have been many support products released,
mostly into shareware or PD. These are available from most FTP sites and
should appear in the Racing Simulators FTP site soon. (This is listed at the
end of this file.) It appears that NO add-on utilities are available for the
Amiga or ST versions, though quite why this is the situation is a mystery to me!
2.1 ** The update disks, 1.04 and 1.05
--------------------------------------
These two update disks were supplied by Microprose, with the first
being sent out by the company. They were supposed to add the facility for
modem play, plus a few other features. 1.05 is the most recent update, and
both are compressed to 1mb and 1.05 is available via most FTP sites.
** What other features were added with the updates????? **
2.2 ** The editors
------------------
At least one editor exists in several versions. The first allows you
to change the relative performances of the cars and the colours of the cars.
The second has only been released recently and allows the changing of crew and
helmet colours.
** Would the authors please supply a small advert and description for this **
** Also the requirements for each program as I cannot run the second **
A MS-Windows compatible editor has recently been placed on several FTP sights
and this one offers the opportunity to
** Any ideas, I don't have time to download it! **
2.3 ** Other editor programs
----------------------------
There are rumoured to be a handful of other programs which provide
features (cheats?) like extra sticks tyres that last the whole race and
programs that allow odd combinations of wings etc. I have not seen any of
these programs, so I cannot tell you where they are available.
2.4 ** Cracks and Password Removers
-----------------------------------
As far as I know there are two cracks available both of which change
the password at the start to a single word, in one case it is "Monza" and in
the other "cars". Apparently there is another crack which runs as a TSR and
enters whatever word the computer requests. There are a few other programs
which change the password and these can also be found in most FTP sites.
Please dont use these cracks to help you piracy attempts, if you like that game
but it, it is starting to appear in the bargain bins now and doesn't cost as
much, and the manual really does help!
** Are these cracks version specific? **
3 Where can I compete against other people?
===========================================
There are currently three championships running, a general one that
anyone can take part in, and a more specific one that you have to register
for, there is also an Amiga championship that has just started.
Amiga Chmpionship - Contact James Smith ([email hidden])
** Could the reps for each championship provide me with a description? **
4 Q+A
=====
4.1 Why doesn't the modem play work?
------------------------------------
If you own the Amiga or Atari ST version then you are out of luck since
the modem support never appeared on either of these versions, the PC game is the
only game with the support.
There is no modem support on the first version (1.01) but this was
added on the updates 1.04 and 1.05, the link option needs two quite fast
machine to work well, on 386sx it is almost unplayable, and the slowest machine
dictates the speed of the other machines.
4.2 Which GP does it default to around the world?!
--------------------------------------------------
Well, on the UK version it selects Silverstone as the default GP, in
France it chooses Magny-Cour, and in Germany it chooses Hockenheim, so it looks
like it depends on what country you live in!
** What about World Circuit etc? **
4.3 What is the best controller method.
---------------------------------------
** I will leave this open to debate on the Net **
Recently a new product has been launched in the United States, this consists of
a Grand Prix style seat, pedal, gears, and steering wheel bolted to a steel
frame! It retails for around $700 and details are available from
** Where please? I lost the address (Very professional) **
4.4 What is the sound like on an SB etc?
----------------------------------------
Not all that much better unfortunately if anything the PC speaker is
more irritating and thus more realistic!! The Amiga sound is reported to be
quite good with a good use of stereo, and the ST is as bad as the PC!
** Again feel free to flame me **
4.5 I am bored with the game, what now?
---------------------------------------
Well it has to happen eventually, so what now? You could join one
of the championships on the Net and learn to really hate the game or try
either of these two very sad games.....
4.5.1 Dodgems
-------------
The basic idea behind this one is to make your car
indestructible and then wipe out the opposition as fast as possible.
Top Tip, go backwards quickly. This is fun for about 16 minutes whilst
you do each of the tracks and marvel at the difference of the courses
when viewed from the other direction.
4.5.2 Jumping
-------------
A particularly rubbish game this, but set your cars up for
no down-force and then drive over the kerbs and become air borne
and see how far you can get. Remember to save the games as you land
so you can show off to your friends and family.........
4.6 Why is the AI (Artificial Intelligence) so
...
read more »
Has anyone tried Formula 1 by Holobytes. It's a new driving sim. but without
all the detail and complexness of Indycar and WC. I haven't tried it yet and
I am wondering if it's worth buying. It seems more like an Arcade style game
without all the setup stuff.
--
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Ken Madore |
______________________________________________________________________________
[alot deleted]
I totally agree - just try playing F1GP with a 32 brake bias towards the rear!
It is OK if you brake in a straight line, but when turning it is like having
no rear wing.
********************************************************************************
* Oliver Roberts | //// Amiga 600 |##### F1GP-Ed ##### *
* (1st Year Comp Sci Student) | //// 2Mb Chip Ram | Now you can *
* | \\\X/// Kickstart 37.350|customize your copy *
********************************************************************************
The speed vector is not weight nor downforce. Combining this with a
shift in weight distribution makes no sense. Weight is a vertical
force. That there are other forces at work pushing the car forward is
obvious, but the weight transfer to the front won't add anything to
the vector pushing the car forward. Otherwise you would be able to
accellerate a car by moving a passenger from the back to the front of
a parked car...
any physics expert around who can shed light on this mystery?
Quoted text (7 lines)
>>I don't think the weight transfer adds much grip on the front wheel since >>it is not a vertical downforce. A bit off the line, this weight transfer >Excuse me, but I must have been really dumb in physics class. Weight is >generally >a vertical downforce... correct me if I am wrong about the location of >the >center of the planet....: The speed vector is not weight nor downforce. Combining this with a
: shift in weight distribution makes no sense. Weight is a vertical
: force. That there are other forces at work pushing the car forward is
: obvious, but the weight transfer to the front won't add anything to
: the vector pushing the car forward. Otherwise you would be able to
: accellerate a car by moving a passenger from the back to the front of
: a parked car...
: any physics expert around who can shed light on this mystery?
While I don't consider myself a physics expert, I think I maybe can
shed some light on this.
While an F1 car has many forces acting on it, these forces can only be
transmitted to the road in 2 directions, vertically and horizontally.
The tires (ideally) only impart forces in the horizontal and vertical
(normal) directions. The key point is that the amount of horizontal
force it can transmit (for acceleration and braking) is directly
dependent on the amount of vertical force on it. The formula is
F = u x N. Where the N is the normal force and the F is the horizontal
or friction force. The u is the coefficient of friction which is
dependent on the properties of *** and the properties of the road
or surface. So for a given coefficient of friction, the bigger the
normal force (N), the bigger the frictional force will be.
The only other forces acting in the horizontal direction are the drag
from the wings and body if the car is at a constant speed. If the car
is accelerating or decelerating, the centre of mass *doesn't* move.
The reason that more force (weight) is transferred to the rear (under
acceleration) is due to the car's moment of inertia, which is directly
related to the *height* of the center of mass of the car. For a given
wheelbase, the higher the center of mass, the greater force will be
transferred to the front or rear. If the center of mass was very close
to the road (as in a go-kart), there would be less shifting of force
from front wheels to back and vice versa.
On an F1 car, the vertical loads (forces) on the tires are determined by
the portion of the car's weight(vertical force)that the tire supports
and the vertical forces imparted by the wings. It would be a lot
simpler if the wings weren't there. Because if you forget about the
downforce from the wings and body, the *total* vertical force doesn't
change, just the percentage shared between front and rear. But when
you consider wings, you have a *changing* total weight. At high speed
the total vertical force imparted on the tires is huge compared to
when its going slow.
The brake bias (yeah I'm eventually getting there ;)) setting (as far
as I understand it) is just the relative braking power imparted to the
*wheels* (front compared to rear). So at an even bias, the friction
between the brake discs and shoes is the same both front and rear. So
if the car was on a jackstand with 4 equal size tires, application of
the brakes would stop the tires at the same time.
The point at which the tire locks is entirely dependent on
the amount of friction imparted on the disc, and the amount of
friction between the tire and the road. But the second value is
directly dependent on the vertical force from the weight and the
wings as was mentioned before.
Lets say we are slowing from 180 to 150...at these speeds, the
downforce from the wings is very high and the weight of the car is
negligible. So assuming that the downforce produced by each wing only
depends on the speed of the air across it, the total wing down force
will be less. But the ratio of the wing downforces (front/rear)
remains the same. Hence the relative braking power from front to rear
to lock all 4 tires remains the same.
Say, for a given speed, the rear wing produces a 50 unit force on the
rear tires and the front wing produces 25 units of force on the front
tires. So if it required 2 units of braking force to lock the rear
wheel, it would only require 1 unit to lock the front. (there is half
the normal force and hence half the friction between front tires and
surface). So to get all 4 tires to lock simultaneously at high speed,
you would need to set the bias to the rear, so that you were providing
twice the braking power to the rear as to the front (1:2 F:R).
But this all changes when the wings become less effective at low
speeds. Then the moment of inertia of the car comes into play and we
see a greater amount of force transferred to the front wheels under
braking. The question is, at lower speeds, does the normal force over
the front exceed that over the back wheels? In a street car it sure
does..but an F1 car has a lot lower center of mass and hence less is
transferred. Lets assume that under braking from 60 to 30, at some
point the force units over the front tires is 40 and over the back
tires is 30. Then we would need *less* braking power at the rear to
lock all 4 tires (higher friction between road and tire at the front
and hence a greater braking force needed to lock it.). This time we
would need braking power in the ratio of 4:3 (front:rear).
So my conclusion is that unless we know what the percentage of wt is
over the front tires compared to the rear at a given speed, we can't
tell if we need more braking power at the front or the rear.
In a road car, aerodynamics play a lesser role, and
the vertical forces are almost always higher at the front than the
rear, and thats why more braking power is needed at the front. There
is a higher normal force and thus a higher friction and more braking
power required to lock it up. That is why they put discs up front and
drums in the rear on many cars.
*If* an F1 car almost always has more force on its rear wheels than its
front wheels, at almost any speed, then the rear bias in F1GP would be
correct.
But if their is a point under braking at which the vertical force at
the front exceeds the rear, then the front bias would be needed.
So there is really only one thing governing where the bias should be,
and that is the ratio of front to rear vertical forces. But the
problem is that this ratio changes with speed. I would be interested
in knowing the ratio of these forces at different speeds..anybody got
this kind of data?
RQ
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Quoted text (7 lines)
|> |> I think the weight vector combined with the speed vector don't make the |> downforce anywhere close to vertical (considering the speed is high). |> Whereas the aerodynamic downforce generated by wings is purely vertical |> downforce. Also the weight of F1 car is very light compare to what its |> wings may generate, if I'm not mistaken it can be as much as 2 tonnes. |>Quoted text (16 lines)
|> |> |> |> |> I think the weight vector combined with the speed vector don't make the |> |> downforce anywhere close to vertical (considering the speed is high). |> |> Whereas the aerodynamic downforce generated by wings is purely vertical |> |> downforce. Also the weight of F1 car is very light compare to what its |> |> wings may generate, if I'm not mistaken it can be as much as 2 tonnes. |> |> |> |> Yes, downforce is generally much higher than the weight of a car, so much so that |> an F1 car could be driven on the ceiling without falling off as long as it went |> over 60 mph. |> |> Anyone want to try this ... ? |> |> SimonI just couldn't resist throwing in my $0.02 on this thread.
The original poster of the physics info (who did a very admirable
job) didn't seem to consider the downforce produced by an F1 car's
diffuser. When this is added to the downforce produced by the wings, the
aggregate downforce can be measured around an aerodynamic ceneter of
pressure. This can be thought of as the center of gravity for the
aerodynamic loads on the car. *Speculation ON* When all is said and done,
the teams try to get the center of pressure to coincide with the center of
gravity so as to produce the most neutral handling car as possible.
*Speculation off* One important thing to remember is that the center of
pressure moves with speed. To what extent, I'm not sure. But it *ALWAYS*
moves rearward. If it didn't, the car would be completely unsafe as it
would produce increasing amounts of oversteer as speed increased. So more
downforce at the rear isn't always a bad thing. I think the original
poster of the physics info knew this, but refrained from it for
simplicity's sake.
The only other thing I want to throw in for a bit of clarification
is that increased vertical load on a tire (downforce in F1) does not
"require" better brakes. It just makes the tire capable of
handling braking accelerations of a greater magnitude. Therefore most
automotive applications employ more braking power in these areas whenever
this advantage can be gained.
Later Folks,
--
******************************************************************************
Bill Mette | "People are personally responsible for keeping themselves
******************************************************************************
Quoted text (11 lines)
>>I think the weight vector combined with the speed vector don't make the >>downforce anywhere close to vertical (considering the speed is high). >>Whereas the aerodynamic downforce generated by wings is purely vertical >>downforce. Also the weight of F1 car is very light compare to what its >The speed vector is not weight nor downforce. Combining this with a >shift in weight distribution makes no sense. Weight is a vertical >force. That there are other forces at work pushing the car forward is >obvious, but the weight transfer to the front won't add anything to >the vector pushing the car forward. Otherwise you would be able to >accellerate a car by moving a passenger from the back to the front of >a parked car...One thing that causes also the weight transfer is surely the
rotation. The simplest example is a chopper where the body
of the plane tends to rotate in the opposite direction than
the rotor. In a car, even when the centre of the mass is
in the same or lower level than the axles, the rotation
generates weight transfer. So, when accelerating an RW car,
the body of the car tends to rotate in the opposite direction
compared to the rear wheels and the front of the car gets lighter.
When braking the effect is:
Front wheels:
Body tends to rotate around the front axle, lifting the rear.
Rear wheels:
Body tends to rotate around the rear axle, pressing the front down.
So, weight is transferred to the front of the vehicle.
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Software Engineer
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: One thing that causes also the weight transfer is surely the
: rotation. The simplest example is a chopper where the body
: of the plane tends to rotate in the opposite direction than
: the rotor. In a car, even when the centre of the mass is
: in the same or lower level than the axles, the rotation
: generates weight transfer. So, when accelerating an RW car,
: the body of the car tends to rotate in the opposite direction
: compared to the rear wheels and the front of the car gets lighter.
Motorcycles provide a good example of this. When given a good shot of
the throttle, the torque from the engine will cause the front end to
lift. And keeping the acceleration high enough, the front end can stay
in the air for quite a long time. Interesting point too. I wonder how
big a part it plays in determining the weights over the front and back
of an F1 car at low speed. With 750-800hp it probably factors in there
quite a bit.
RQ
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: One important thing to remember is that the center of
: pressure moves with speed. To what extent, I'm not sure. But it *ALWAYS*
: moves rearward. If it didn't, the car would be completely unsafe as it
: would produce increasing amounts of oversteer as speed increased.
Does it move? Perhaps I'm oversimplifying things here, but doesn't the
downforce of each wing (and the diffuser) depend on the velocity of
the wind over their surfaces? So, at first glance, it would seem that
the ratio of downforces produced by these elements(the wings,body and
diffuser) would remain relatively constant with speed. But maybe one
element becomes effective at a later time (higher speed) than the
others. I'm not sure. But to me it would seem that above a certain
speed (where aerodynamics start playing the major role), the center of
pressure would remain in the same position. This would be good,
because the overall balance of the car would stay the same whether you
were driving 100 or 180. This to me would be safer because the driver
could better predict how his car is going to handle in a given
situation.
: The only other thing I want to throw in for a bit of clarification
: is that increased vertical load on a tire (downforce in F1) does not
: "require" better brakes. It just makes the tire capable of
: handling braking accelerations of a greater magnitude. Therefore most
: automotive applications employ more braking power in these areas whenever
: this advantage can be gained.
In racing applications, I would think that the object would be to
*not* have one end of the car lock before the other, so thats why I
put it into terms of what relative brake power is required to lock all
the tires simultaneously. By this I was meaning that at this magic
bias, (when you would have all 4 lock at a given speed), you would
effectively have all 4 tires contributing the same amount to overall
deceleration. This would seem to me to be the most stable and fastest
way to brake. But I think the ideal bias changes for every different
situation so the "ideal" setting is at best a compromise.
Also, I remember reading something from Mark Blundell last season,
where he said that the wings on his Ligier were flexing a little more
than they were supposed to at speed. So maybe theres even another
factor coming into play here. It sounds like the wings are designed to
flex a certain amount at high speed so that while their downforce
decreases a certain amount, so does their drag, leaving a higher top
speed. Then when the car slows, the wings return to their more upright
shape and provide more drag but higher downforce. So to some degree,
you have "active" aerodynamics but with the wind doing the work
instead of electronics..This would lead to a
shifting of the center of pressure, but I wonder how big the effect
is. And there must be some force wasted on bending the wings down, but
maybe it is small relative to the gains they make in top speed. There
are probably hundreds of things that these F1 engineers take into
account that we can't even pronounce! :-)
Later,
RQ
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Wow! A lot of talk being thrown around, now it's time for Jeffrey
the bombast to get his $.02 in....
A few pointers- The F=u X N equation is not entirely correct. Since the
tyres adhere to the track mechanically as well as chemically, you will
get a constant friction factor, regardless of load (ie, normal force)
or static/ dynamic friction.
Since we're talking vectors here....
OK, a nitpick- velocity is a vector, speed is a scalar. Had to get that
in there. Anyway, the forces experienced by the car, (geez, it's been
years since I took dynamics!) are, as explained before, horizontal and
normal, or into/out of the track. Friction is horizontal, and as usual,
opposes motion. Since the speed (not velocity ;) of the tyre is ZERO at
the point of contact (else it spins and smokes!) static friction AND
chemical adhesion comprise the force that pushes into the track, and
the track responds by puching the car down the road. Confused? Me, too!
As far as brake balance goes....this has little to do with the downforce.
The reason brakes are traditionally adjusted forward is simple- since the
car leans forward (front dives) there is more weight transmitted to the
front. This occurs in winged cars like a Williams, or my Saturn, or cars
that people foolishly spend money on to fund the Japanese Wehrmacht.
Ask anybody who locked up the front on a bike, or flew off a motorcycle.
The front dives. OK, so you want the fronts to lock first, since by
locking first, they can stop faster, provided more weight is applied.
The idea in perfect braking is to 'scrub' the front- lock impending,
but SLOWLY turning to scrub the *** off at an even rate. Meanwhile,
the backs also brake, but since the normal force is less (it's all in
front) they merely turn slowly, not scrubbing.
In rain, the situation is reversed- water is probably one of ***'s
best lubricants....since the chemical adhesion is minimized in the wet,
the probability of lockup is much higher, and this kills the steering.
So in rain, it's better to have the rears lock first- at least, this way
the thing will steer.
SUMMARY (Finally!!)- Set brake balance forward in the dry.
Set brake balance backward in the wet.
Don't sleep as much as I did in Statics/Dynamics
Watch Sunday's GP of Monte Carlo at 9:20 AM
(EST) on ESPN. Then tape the BBC feed.
Anybody got any questions? Hope I'm not sounding arrogant :)
Post or e-mail. Later!
+--------------------------------------------------------------+---------------+
|"Sometimes I try to beat other people's achievements but on |JK Salzmann |
| can give me more satisfaction. I don't feel happy if I am +---------------+
| comfortable. Something inside me pushes me when I get comfortable. |
| It makes me go further and want to keep pushing" - Ayrton Senna, 1960-1994 | +------------------------------------------------------------------------------+
Quoted text (16 lines)
>One thing that causes also the weight transfer is surely the >rotation. The simplest example is a chopper where the body >of the plane tends to rotate in the opposite direction than >the rotor. In a car, even when the centre of the mass is >in the same or lower level than the axles, the rotation >generates weight transfer. So, when accelerating an RW car, >the body of the car tends to rotate in the opposite direction >compared to the rear wheels and the front of the car gets lighter. >When braking the effect is: > Front wheels: > Body tends to rotate around the front axle, lifting the rear. > Rear wheels: > Body tends to rotate around the rear axle, pressing the front down. >So, weight is transferred to the front of the vehicle.Quoted text (10 lines)
>: One important thing to remember is that the center of >: pressure moves with speed. To what extent, I'm not sure. But it *ALWAYS* >: moves rearward. If it didn't, the car would be completely unsafe as it >: would produce increasing amounts of oversteer as speed increased. >Does it move? Perhaps I'm oversimplifying things here, but doesn't the >downforce of each wing (and the diffuser) depend on the velocity of >the wind over their surfaces? So, at first glance, it would seem that >the ratio of downforces produced by these elements(the wings,body and >diffuser) would remain relatively constant with speed. But maybe one: PS - Does anyone object to holding this conv. here? It should probably be in
: rec.autos.sport.
Actually, there is a more appropriate newsgroup: rec.autos.tech, where
it probably should be taken.
Later,
RQ
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: According to Carroll Smith's "Tune to Win" and a few articles from Racecar
: Engineering,
SOunds like some interesting reading. I will look for the book. How
old is it? And is Racecar Engineering a magazine? If so, where did you
get it? (Not at the local newstand I assume.)
: Re: Mark Blundell's statements about wing flex.
I'll try and dig up the article this weekend and re-read it to see
what he says..
Later,
RQ
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[ stuff deleted ... ]
Nope.
I'm going to jump in to this. And I'm probably not even going to use the
correct technical terms. :-) In a race car you always want the fronts to
lock first (some racers will disagree but this is a good rule). When the
fronts lock first you at least go in a straight line. When the backs lock
first they also lose sideways traction so the backend comes around :-(.
The brake balance is adjusted based on how much weight is being transferred
to the front wheels. The more weight transferred to the front wheels the
more force you can apply to the brakes without locking them. More weight
is transferred to the fronts on dry pavement because there is more grip.
MUCH less weight is transferred to the fronts in the wet because there is
less grip.
|> SUMMARY (Finally!!)- Set brake balance forward in the dry.
|> Set brake balance backward in the wet.
Yes.
|> Don't sleep as much as I did in Statics/Dynamics
:-)
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Mentor Graphics Corporation (Wilsonville, OR)
87 VW GTI 16V 85 VW Golf (race car) #32 - Conference Production H
Quoted text (18 lines)
|> As far as brake balance goes....this has little to do with the downforce. |> The reason brakes are traditionally adjusted forward is simple- since the |> car leans forward (front dives) there is more weight transmitted to the |> front. This occurs in winged cars like a Williams, or my Saturn, or cars |> that people foolishly spend money on to fund the Japanese Wehrmacht. |> Ask anybody who locked up the front on a bike, or flew off a motorcycle. |> The front dives. OK, so you want the fronts to lock first, since by |> locking first, they can stop faster, provided more weight is applied. |> The idea in perfect braking is to 'scrub' the front- lock impending, |> but SLOWLY turning to scrub the *** off at an even rate. Meanwhile, |> the backs also brake, but since the normal force is less (it's all in |> front) they merely turn slowly, not scrubbing. |> |> In rain, the situation is reversed- water is probably one of ***'s |> best lubricants....since the chemical adhesion is minimized in the wet, |> the probability of lockup is much higher, and this kills the steering. |> So in rain, it's better to have the rears lock first- at least, this way |> the thing will steer.Quoted text (7 lines)
|> |> : PS - Does anyone object to holding this conv. here? It should probably be in |> : rec.autos.sport. |> |> Actually, there is a more appropriate newsgroup: rec.autos.tech, where |> it probably should be taken. |>: |>
: |> : PS - Does anyone object to holding this conv. here? It should probably be in
: |> : rec.autos.sport.
: |>
: |> Actually, there is a more appropriate newsgroup: rec.autos.tech, where
: |> it probably should be taken.
: |>
: I disagree. This group is about simulation as well as simulators.
: I, for one, find the topic interesting as it tells me something about
: what I might expect of realistic simulators.
Good point. But there is also a lot of knowledgeable people over there
who would probably be quite good at shedding more light on the
subject. That is the only reason I suggested that group. By all means
continue it here, either way I find it very interesting.
Later,
RQ
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