A very belated update to my car thread...
Results from round 1:
Coefficient of lift: -2.854
Coefficient of drag: 1.548
Center of pressure: 2.122m
I managed 3rd in round 1. The car had a good amount of downforce but it was far too draggy, being the draggiest of all the competitors. For Magny Cours I figured that I would go for absolute maximum downforce, but I really should have kept an eye on L/D.
Another big problem was the F/R balance - by my own testing I had it pretty close to the ~1.8m optimum, but I guess the difference in mesh settings between my tests and the KVRC simulation meant that I ended up quite a long way off.
Round 2 was Monza, so given that and the fact my round 1 car was very draggy, the obvious priority was drag reduction, followed by F/R balance. Main changes for round 2 (among many other small tweaks):
-Rear wing and beam wing profiles made far less aggressive, monkey seat removed
-Beam wing split into two parts, one either side of the gearbox (since the spec gearbox/crash structure is quite high)
-Smaller diffuser gurney, especially in the free y75 area
-Reworked bargeboard and floor leading edge (moved rearwards a bit)
-Removed turning vanes under the nose
-Front wing reworked to balance out the new rear DF level
Results for round 2:
Coefficient of lift: -2.525
Coefficient of drag: 1.151
Center of pressure: 2.148m
I managed to win round 2 with very low drag and reasonable downforce, though the results were close. I didnt fix the balance problem, which was disappointing.
Round 3 was Silverstone. While I would need more downforce than round 2, the results from the first two rounds showed that drag is punished fairly heavily, so I was aiming for a fairly low drag target. So I used the Monza car as a base, with the following modifications:
-Rear wing and beam wing profiles somewhere inbetween the wings for round 1 and round 2
-Beam wing returned to full width
-Different concept for the center of the diffuser
-More tweaks to the bargeboards and floor leading edge, no real gains here over round 2
-Added turning vanes under the nose, more efficient than the version from round 1
-Front wing completely reworked for much more front downforce
I finally managed to sort out the mesh settings at this point - for the first two rounds, the size of the mesh used in KVRC was such that the slot gaps in my front wing were being meshed over, so I had much less front downforce than I expected in round 1 and 2 - hence the balance problem. For round 3 the slot gaps in the front wing were made much larger, which pushed me towards a 2 element front wing. I also moved to away from having a slotted diffuser gurney, since details like this were far too small to be carried over into the final mesh.
In retrospect, I spent too little time on the front wing. I started off with changes to the rear of the car, assuming that front downforce would be easy to find. In reality I was front limited, had I focused on the front wing first I could have found more front downforce and then easily added more rear wing.
Results for round 3:
Coefficient of lift: -2.645
Coefficient of drag: 1.243
Center of pressure: 1.837m
I managed to win round 3. I was very happy to finally get the F/R balance spot on which was important, as I was beaten by JJR for overall downforce but I had a quicker lap time because of CofP and drag (although there wasnt much in it in L/D).
Even though the overall downforce level wasnt much higher in round 3 compared to round 2, the useable level of downforce was substantially higher because the F/R balance was pretty much perfect. For pure L/D there was a lot of rear downforce left on the table, but adding it would have only given a slower result because the balance would shift away from the optimum, and drag would be higher.
With that I managed to win the championship
More info on KVRC here -
http://www.khamsinvirtualracecarchallenge.com/home
the car looks fantastic and it's great to see that backed up with strong performances
