rec.autos.simulators

First of all, apologies for any double-aa's that creep into this text -
my keyboard is a bit knackered!

Couple of questions about race strategy, specifically aimed at GP2 but I
suppose probably apply to ICR2 and NASCAR aswell.

1. Fuel Load - I accept that less fuel equals greater straight line
speed, because the car is lighter. But, on twisty circuits where I would
set up with a lot of downforce, would having a heavier load of fuel
increase the grip of my car through the corners?

2. Tyre Wear - Subjectively, how much tyre wear is tolerable before
performance suffers too much? The set-up screen shows tyre wear up to
4mm, but should I be looking for a change before this?

3. Pit Stops - Okay, so maybe this is a little unrealistic in GP2, as my
pit guys can replace all four tyres, fit a new front wing and mend an
oil leak in 8.8 seconds! Nevertheless, is there a formula or something
similar that I can use to work out the relative benefits of one, two or
three stops? How do the teams in real life judge this?

4. Race Position - How do the factors above vary with the position I
qualify? If I get pole (yeah, right!) should I be looking to stay out as
long as possible, or set up with a light load to race ahead as far as
possible?

Thanks in advance for any thoughts anyone is willing to share on this.

Long live GP2 and God save Geoff Crammond!

regards,

Paul

***********************************************************************
*             Paul L. Finnemore - Apprentice Veterinarian             *

*    "Auto-brakes? I don't need no stinking auto-braaaahhhhh....!"    *
***********************************************************************

I'll try to answer in a general race strategy mode.  As I had to work
til the stores closed today and my USA copy of GP2 is still sitting in
the store :(

: Couple of questions about race strategy, specifically aimed at GP2 but I
: suppose probably apply to ICR2 and NASCAR aswell.

: 1. Fuel Load - I accept that less fuel equals greater straight line
: speed, because the car is lighter. But, on twisty circuits where I would
: set up with a lot of downforce, would having a heavier load of fuel
: increase the grip of my car through the corners?

In real life racing, it really would depend on the location of the fuel
cells.  But, I would hazard to guess that the benefits would be
outweighed by the weight.  Also your handling is affected by the
"larger" weight shifting (trying to throw around extra weight).  But how
closely any of the sims model this is beyond me.  The extra weight can
also affect your tire wear.

: 2. Tyre Wear - Subjectively, how much tyre wear is tolerable before
: performance suffers too much? The set-up screen shows tyre wear up to
: 4mm, but should I be looking for a change before this?

When you begin to feel it.  Some drivers can drive almost as fast on
worn out tires as they do on fairly fresh ones.  However, there does
come a point where it's too dangerous.  It used to be that it was always
the driver's call in F1 to come in for new tires.  But, I am sure this
has changed alot with the "fuel" strategies being played out now days.

: 3. Pit Stops - Okay, so maybe this is a little unrealistic in GP2, as my
: pit guys can replace all four tyres, fit a new front wing and mend an
: oil leak in 8.8 seconds! Nevertheless, is there a formula or something
: similar that I can use to work out the relative benefits of one, two or
: three stops? How do the teams in real life judge this?

The actual time in the pits usually isn't what kills you.  It's the
slowing down to enter and the time it takes you to get back up to speed
and warm up the tires that counts.  That's why Schumacher always used to
beat the pants off of Damon Hill.  He's a master at entering and
exiting the pits.  He could even have a slower pit stop than Hill and
still have a better overall lap time.  God, what I wouldn't give
to have a pit crew like GP2 does in Indycar or NASCAR.  But, you also
have to keep in mind that you can have 40 guys out there working on your
car in F1, we're limited to the number of crew in the pits for Indy &
NASCAR.

: 4. Race Position - How do the factors above vary with the position I
: qualify? If I get pole (yeah, right!) should I be looking to stay out as
: long as possible, or set up with a light load to race ahead as far as
: possible?

There are alot of variables to consider.  How well do you conserve your
tires?  How well do you enter and exit the pits?  What game plan does
your hottest competitor have in mind?  Ah, that's why I'm glad they
brought pit stops back into F1.  They had to add some sort of suspense.

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

[snip]
|> 4. Race Position - How do the factors above vary with the position I
|> qualify? If I get pole (yeah, right!) should I be looking to stay out as
|> long as possible, or set up with a light load to race ahead as far as
|> possible?

I guess if you're on pole, go for a light fuel load so that you can open up
a big lead. That's assuming you have a good start (you don't happen to be
Damon "I won't win if I don't get the lead in the first corner" Hill, heh?).
If you are not on pole, go for a heavier fuel load so that you can have less
stops and stay out longer. Especially if you are stuck behind some mobile
chicane which will diminish your advantages of a lighter fuel load.

Can't wait anymore to get my hands on GP2! We Canadians are last!

--
Isaac Wong  (613) 763-6127 | Compiler Development, Public Carrier Networks

On Wed, 24 Jul 1996 18:03:41 +0100, "Paul L. Finnemore"

Fa = m * v * v / r

Then there is another force which ensures you have grip:

Fb = m * g * y (+ downforce)

where:
r = radius of the curve.
m = mass of the car.
v = velocity of the car.
g = gravitational constant
y = friction coefficient (between wheels and track)

If Fa is less than or equal to Fb, then you stays on track, otherwise
you loose traction and skates of the track.

or in mathematical terms:

Fa <= Fb

which equals

m * v * v / r   <=   m * g * y (+ downforce)

The mass can be left out on both sides, and then gives:

v * v / r   <=   g * y (+ downforce)

Conclusion:

The mass has no influence on grip through corners.

But increased mass will increase acceleration time and brake lenght,
and also decrease top speed due to more friction in bearings, so you
really don't want a heavy car.

Hope this helped (...and someone tell me if I need to go back to
school.....!)
--
Lennart Gr?nlund

http://www.pip.dknet.dk/~pip2351/

Julian

_____________________________________________________________________

                                University of Oxford

In GP2, fuel load doesn't seem to make much of a difference to car handling
though, much less than In ICR2. F1 cars do carry less fuel than Indy though.

Julian

_____________________________________________________________________

                                University of Oxford

This is where you start to go wrong. To a (VERY (No flames!)) simple approx:

     downforce = k x v

(I prefer x as a multiplication symbol instead of * and k is some fixed const).
As you lightly skip over the problem of downforce, you neglect the fact that
increasing the fuel load in a vehicle will increase the load down upon the
tyres AND will increase the centrepetal force equally.

BUT the aerodynamic downforce (do to wing+ground effect etc), will not vary,
save possibly due to a slightly different ride height (as the car lightens,
the springs reach equilibrium further from the ground - they aren't squashed
as far).

Therefore, as the fuel load decreases, the force downwards upon the tyres
increases compared with the force outwards due to the mass of the vehicle.
So as the fuel load decreases, the force Fb is proportionately larger than
Fa.

Conclusion: You can corner faster with less fuel in your vehicle.

(Hint: since downforce=k x v you the fuel load changes handling more at
high speeds than low ones. This also the reason why your brakes lock up
more easily at low speeds. Downforce and fuel load are negligible in
most road-cars. Ferrari F50 owners can***off...)

Not so. See above.

                                         ^^^^^^^^^^^^^^^^^^^^

Probably not simulated. :-)

You are few; we are many.
  -- Lurkers motto.

-- Andy
_______________________________________________________________________________

| "...the enemy of the market is not ideology, but the engineer."J.K.Galbraith|

: Find out the lap times of the slowest cars during the pre-race warm up.
: Then assume that by the end of the first lap, the slowest cars will be
: about 30 seconds behind the leader. From this you can work out what lap
: you will start to reach the backmarkers on. Plan your first pit stop for
: then, and you won't get caught in traffic too much.

This brought up a question that I haven't thought of trying out.  What
happens if one calls a pit stop earlier than the pre-planned stop?
Let's say your are mired in traffic and want to pit 5-6 laps early.
If you planned on a 2 pit-stop strategy and this is your 1st stop, will
the pit crew readjust the early pit stop's fuel load to get you to the
next 2nd planned pit-window?

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

On Sat, 27 Jul 96 22:09:32 GMT, Andrew Haigh

You have opened my eyes  :-)

Fa <= Fb + downforce

The equations I have stated is still true, but my conclusion was
wrong. Fa and Fb is reduced equally when the mass decreases, but I
ignored the fact that the downforce is independent of this fuel
decrease.

True, and my original conclusion:

still goes for racetracks on the moon and other non-atmosphere places
where downforce is off topic......     :-)
--
Lennart Gr?nlund

http://www.pip.dknet.dk/~pip2351/

The selection is done on the steering wheel display in the same way as
the tyre selection and leave pits etc. options when not in a race.

WHOOPS!!!!

Your thing looked pretty good there until you dropped mass out of the
equation.  Downforce is as you said a force and therefore your
Fa <=Fb where Fb =F(weight)+F(downforce)  works well.  When you devide
out mass you get V^2/R <=  g*y* [1+F(downforce)/M]

So Mass makes a HUGE difference in a twisty course.  Think of it this
way.  If the car weighed nothing but had 1g of downforce you could
turn instantly (no mass to change direction but some force to create
friction).  So if the Mass is small compared to the Downforce the car
handles well in corners.  

BTW not guaranteeing the rest of the equation just ensuring that it
should have Mass in it when all is settled :)

Eric Fesler

On Sat, 27 Jul 96 22:09:32 GMT, Andrew Haigh

How do we rectify this situation, since this was always an idea completely
taken for granted by me (and I thought most people)?  If someone can spit
out a formula for friction depending on normal force and coefficent but
boggle this idea (remember Newton's laws?!?), we all need to pay more
attention to HS Physics.

Gregory Fung

Vancouver, B.C., Canada

I don't think Mr Crammond went to Harvard. British doncher know?

The mechanics was the Newtonian kind I learnt at school.

Naturally, you don't have to know anything much about how to drive
or setup in theory. Just change what you do until the the laptimes
decrease.

Also obtain setups from others who drive faster/know more on the web.

In desperation, you can try bribing the computer.
(Hint: This will not work.)

Bye,

-- Andy
_______________________________________________________________________________

| "...the enemy of the market is not ideology, but the engineer."J.K.Galbraith|