Formula-Retro drivability

That also explains why there is no front wing adjustment for the BT44... I was just speculating before, but it seems to be the fastest car of the lot, and there is no front downforce adjustment, but it's clearly modelling downforce for the whole car... I bet it is modelling some slight amount of ground effect. Perhaps the model for this is accurate or inaccurate, and that may have something to do with the twitchiness over crests. I know the 72E doenst like the little kink before the Jochen Rindt Curve at Spielberg, but you CAN control it now. It's not the instant snap off death that it was on day 1. Ive got a few offs there, but I've also been able to apply some opposite lock and keep my foot planted too, so I dont think the 72E is as sensitive to it as the BT44.

 

very interesting, please more discussion, technical backround and your experience, I want to drive F-Retro on thursday and need more input

 

Just to throw in a few bits of information.

1. Ickx on the 74 Lotus 72 "It's so difficult to find the limit. You put that tail out so far you think you must spin but then the car begins to grip even better. It's fabulous really".

2. The default Limited Slip Diff setting is around 10% locking for power and coast. This is essentially an open diff although there is the locking from the pre-load.

3. The Lotus 72 used Hewland's cam and pawl limited slip diff which was a licensed version of the ZF cam and pawl. It typically has a bias ratio of 3:1 which is equivalent to a locking % of 50% which would be a 33 degree ramp with 4 clutches. The descriptions of how it operates say it locks on power but doesn't lock on coast so leave the coast side at the default. Because it locks, the clutch pack diff is the best option to simulate it, but it has no pre-load so take this away.

4. I don't currently have any data on the Salisbury limited slip diffs which were entering use in F1 in this period. However, limited slip differentials for racing were typically in the range of 40% to 75% locking with some cars even resorting to spools.

 

Once in 2004 or 2005 Juan Pablo Montoya groaned that not the car is giving the limit, the driver is the limit. There's no fun anymore. And this from a driver who hit the car around the tracks as noone else.

 

What effect does the number of clutch plates have on diff tuning?

 

Yes but is more clutch plates more friction or less?

 

Ive turned up the clutches quite a bit and lowered ramp angles quite a bit but it sometimes doesnt seem like it's doing much. When I switched to the geared diff it starting acting a lot closer to how I wanted it to. I know it's not period correct, but I think it feels about right.

 

I've tended to prefer the geared LSD, but I do keep switching back and forth.

 

I'd feel better about it if I was as fast as you guys!

Heres another cool video for you guys to review!

Im amazed at how much F1 coverage is on youtube from those days!

 

Yeah I noticed the same thing. It's never quite as wild as what I'm doing sometimes, but you can definitely see a good 5-10 degree deviation between car angle and the velocity vector.

 

With the loved GPL, we used to had ramp angles 30,45,60 and 85 and six clutch plates. With ramp 30 and 2 clutches you got almost the same lock as using 85 with 6 clutches, the difference used to feel as timing versus aggresiveness.

I think the ramp acts more mechalicaly, as a gear, while friction clutches could feel more elastic.

I feel I'm talking as my grandphather lol

 

Okay, this is starting to make sense now. So even with pretty lose ramp angles, if I have a lot of clutches, the coast side can still grab pretty hard.

I just remember using Gregor Huttu's diff setups and hoping for the best.

 

Hahaa! These cars do seem to be bringing some of us old GPL'rs out of the woodwork!