rec.autos.simulators

In spite of all the development that went into GTR, the developers
admitted that the German version 1.0 was too spin prone and addressed
this in the later versions.

My issue is not so much a physics issue, but a feedback issue. It's
difficult to push the the throttle inputs to the limits on any simulation,
because there are no forces to feel. The question is should the simulation
compensate for the lack of feel by making the cars more forgiving?
Ok, the assists are one way of doing this, but it's not quite the same.

Regarding the physics of GTR, is why doesn't induced understeer (pegging
the steering inwards to wash out the front end) work? Real racers
use some amount of induced understeer in mostly two situations: under
braking on a car that would otherwise be spin prone; on very high speed
turns with non-downforce cars because generally the throttle is pegged
just to maintain high speed against aerodynamic drag.

In comparing GPL to GTR, I submit the video below as an example, a Greg Stewart
hot lap at Rouen. You see induced understeer, counter steering and a lot
of steering corrections made at a rate that seems to match reality. With
GTR and other games, the steering inputs are done at a lower rate, mostly
because the feedback just isn't there for those subtle but quick
corrections. The force feedback in GTR and many other games is almost like
a steering assist, which dampens out some of the subtle steering corrections
a player needs to make. The physics in GTR may be better, but which game
GPL or GTR, gives the player a more realistic experience?

Personally, I'm decent, but not expert at either game. My GPL rank is -10,
negative on all track, with an 8:15 at Nurburg Ring my relative best.
My best lap time with GTR 1.4 at Spa is a 2:14.7 using a momo racing wheel
and pedals, and 2:15.4 when using twin joysticks (no force feedback) and
assists on.

Dual view video (top is on board, bottom is chase) of Greg Stewart at
Rouen:

http://www.racesimcentral.net/

You may have isolated our differences there.  I think GPL is more
forgiving, but also has some truly bizarre behavior with regard to
things like setups and (too) rapid control inputs.  I'll take accurate
physics instead and cope with the fact it's a computer simulation.

I have dial up so a 30M file is out of the question, but I've seen
plenty of GPL laps with "rapid inputs".  They wouldn't work in a real
car, and they don't work in GTR, which is why they're not used, not
because of lack of feedback.  Also, in a real race car, countersteering
is a desperation move to save a car.  It's dog slow on pavement.  But
it's used extensively in GPL hot laps I've seen.

It depends on the car. Here's a link to a maniac in a Porsche at
Nordschliefe (old Nurburg Ring), with inputs just as rapid and severe
if not more as what I've seen in GPL, plenty of countersteering too.
Maybe it's just the nature of rear engine low downforce cars.

http://www.green-flag.com/pages/welcome.php?id=nurburgring&id2=videomenu

Thats 'Sideways Stephan' and he does it just for show on the RUF videos

Fast porsche laps at the ring look slower as they're tidy
eg:
http://vanadium.prg.dtu.dk/~pmc/andersj/200209_GT3_745.WMV

--

Robin

         It doesn't depend on the car that much.  Sideways is never
fast.  If the tires are at that slip angle, they ain't developing max
cornering force, for sure.  Seems like you've been looking at some bad
examples; Tiff, "Sideways Steven".

         My final thoughts (I'm done here, but I'll read responses).
If the GTR cars on radial slicks with downforce _weren't_ a lot less
forgiving than GPL cars on narrow bias treaded tires with no downforce,
_that_ would be highly unrealistic.  The setups (basically go-carts)
and driving style that leads to the fastest laps on GPL are not
realistic ones.  That is not true for GTR.

That explains it.

If you look at actual lateral force versus slip angles there's
not much, if any loss in laterforce at higher slip angles, except
for the fact that tires get overheated. Avon is one company that
publishes this data, and Todd Watson, who has been working on
basic simulator physics, has done a lot of research on this
consulting experts, and there's little loss of grip at higher
slip angles, it's just the lateral force is not quite in the right
direction.

It also depends on tire contruction. IRL (Indy) cars have the
smallest "working slip" angle of about 2 degrees. F1 and Cart cars
are more like 2.5 to 3 degrees. Most non-downforce racing cars
wihtout tire restrictions will use bias ply slicks, with a slip
angle around 4 to 5 degrees.

Yes I agree with this, I feel that some aspects should be
compromised to make up for the lack of feedback. Traction control
is one way, and realistic, since it's used in FIA's F1 and GT1
classes. Champ cars don't use traction control, but looking
at videos of events at Laguna Seca and Brands Hatch, there are
a lot more incidents than in F1, maybe fun for the spectators,
but not the drivers and teams.

If GTR's physics model is implemented so that lateral force is
reduced at excessively high slip angles, then why doesn't
pegging the steering wheel induce a large amount of understeer?

Somethings up with the physics.

I've tested this in real life on a Trans-Am (front weight bias
car), and a Caterham (rear weight bias car), and it works well
on both cars. In addition, I've seen posts about this method
being used by many club and professional racers.