2017-2020 Aerodynamic Regulations Thread

[Just_a_fan]

~5600N front, ~6600N rear is how I read it which gives a balance of ~45.9%. There is also a note of CI = ~5.3, CX = ~1.5 which I assume are L and D giving L/D of ~3.5. Would that all seem about right?

[Just_a_fan]

~6600N F, ~8400N R works for balance of 44% so that could also be the figures.

[garyjpaterson]

~6600N F, ~8400N R works for balance of 44% so that could also be the figures.

Yeah i think thats it, if you play/pause the video at 0.25 speed you can read the values a bit clearer as it zooms.
Also of note it the telemetry looks a lot like Barcelona judging by the speed trace.

[henry]

Does aero balance match static balance at this sort of speed?

I thought they shifted balance to the rear at speed to help with stability through high speed turns.

[jjn9128]

~5600N front, ~6600N rear is how I read it which gives a balance of ~45.9%. There is also a note of CI = ~5.3, CX = ~1.5 which I assume are L and D giving L/D of ~3.5. Would that all seem about right?

I didn't see the Cx and Cz. They both seem high, so I'd guess they're CzS, CxS, if frontal area is 1.6m*m that's Cz ~3.3, Cx ~0.94... that downforce seems low and that drag seems high, and an L/D ~3.5 would be low these days. They also say body so maybe that doesn't include wheel forces, but I'd expect less downforce and more drag when looking at the total... ride height says 5mm front 33mm rear (?) could be some sort of stall behaviour, that's a rake ~0.43 using last years wheelbase, which puts the front of the plank scraping on the ground.

I just can't work out a combination of numbers which gives that balance and downforce coefficient. 5.6kN/6.6kN gives a CzS of ~5.9, it could be they expected people to obsess over it so put a bunch of silly numbers in

[garyjpaterson]

~5600N front, ~6600N rear is how I read it which gives a balance of ~45.9%. There is also a note of CI = ~5.3, CX = ~1.5 which I assume are L and D giving L/D of ~3.5. Would that all seem about right?

I didn't see the Cx and Cz. They both seem high, so I'd guess they're CzS, CxS, if frontal area is 1.6m*m that's Cz ~3.3, Cx ~0.94... that downforce seems low and that drag seems high, and an L/D ~3.5 would be low these days. They also say body so maybe that doesn't include wheel forces, but I'd expect less downforce and more drag when looking at the total... ride height says 5mm front 33mm rear (?) could be some sort of stall behaviour, that's a rake ~0.43 using last years wheelbase, which puts the front of the plank scraping on the ground.

I just can't work out a combination of numbers which gives that balance and downforce coefficient. 5.6kN/6.6kN gives a CzS of ~5.9, it could be they expected people to obsess over it so put a bunch of silly numbers in

I'm getting pretty close with the downforce coefficient when you factor in the car mass and a bit of fuel.

Car + 30kg fuel = 764kg.
Total vertical load on the tyres (assuming I'm reading it correctly) is 30317N or 3091kg.
That is 2327kg of downforce, which with air density of 1.25kg/m3 results in 5.38 Cl*A
Im getting 44.2%F total balance though.

[jjn9128]

I'm getting pretty close with the downforce coefficient when you factor in the car mass and a bit of fuel.

Car + 30kg fuel = 764kg.
Total vertical load on the tyres (assuming I'm reading it correctly) is 30317N or 3091kg.
That is 2327kg of downforce, which with air density of 1.25kg/m3 results in 5.38 Cl*A
Im getting 44.2%F total balance though.

Oh gosh, I'm so aero-centric I assumed they were just aero loads. Obviously weight is going on there. Which means you have to subtract the weight distribution from the wheel loads. If we're saying 6600N Front, 8400N rear? Dry balance is ~54% rear, that table suggests 65% (rMechanicalBalance?) rear, which seems really far back, but there will be weight transfer from the aero loads plus fuel is rear/mid on the chassis!?

I'm going to need a spreadsheet...

[jjn9128]

From my best reading of the table... 105kg of fuel required to match the CzS... if anyone wants to dispute the numbers I'll have another go!!

[Dynamicflow]

https://bz5boq.by.files.1drv.com/y4mTGV ... pmode=none
From my best reading of the table... 105kg of fuel required to match the CzS... if anyone wants to dispute the numbers I'll have another go!!

..and what about front and rear tyre lift?

[jjn9128]

..and what about front and rear tyre lift?

Well that's my problem, I can't work out what the Cx and Cz mean - Cz =5.3 is probably too high for total DF (expect <4) but is lowish if it's CzS. Cx =1.5 is really high for total or body drag (expect <<0.9 for total) but is about right if it's total CxS. IF that doesn't include wheels forces that might explain the downforce (though wheel Cz >1.3 may be on the high side), but drag would end up pushing Cx or CxS=2... which is absurdly high.

So I can't work it out. If I reduce fuel to 0kg then Cz (/CzS) =5.53...

[MtthsMlw]

Some nice illustrations of the 2019 aero changes.
[media]https://twitter.com/afalcdesign/status/ ... 5114872832[/media]

[ESPImperium]

I always thought that those stupidly narrow wings circa 2009-2016 should have been paired with the front winds circa 2006-2008 to create a car that was a bit more balanced. With those lovely large slick tyres we had in 2009 and getting more downforce from the floor we would have had a good technical formula. DRS would need a tweak, made to be used tactically and not with that stupid 1 second rule.

[roon]

Some nice illustrations of the 2019 aero changes.
https://twitter.com/afalcdesign/status/ ... 5114872832

Humble suggestions:

• Combine the rear crash structure and the exhaust for maximum neutrality. Simplified appearance.
• Combine mirrors, halo, cameras and ers lights into one component. Cleans up the car.
• Wider RW to match the FW. Full width a la LMP/GT. Thinner, lower.

[Sevach]

Slight ot, Indycar reduced downforce levels for this season... and we had one of the Indy 500's with less overtakes that i can remember and everyone complaining how it's impossible to follow.

The black art laughs in the face of theories again.

[jjn9128]

Slight ot, Indycar reduced downforce levels for this season... and we had one of the Indy 500's with less overtakes that i can remember and everyone complaining how it's impossible to follow.

The black art laughs in the face of theories again.

Difficult to find values for the downforce of these cars but I've seen 5000lb (obviously horrendously rounded) quoted for Indycar on road courses and ~1/2 that for speedway. That's a Cz =2.87 based on a reference area of 1.6m*m (CzS =4.6) in road configuration, Cz =1.44 (CzS =2.3) on ovals - compared to F1 that's about 20% less downforce in road config and ~60% less on the ovals. They say the floor generates 66% on road tracks and 88% for ovals, so the underbody Cz is 1.9 and 1.3 respectively. F1 cars produce ~65% of their downforce from the floor which is an underbody Cz =2.3... I've never got the arguement that more floor downforce is the cure all solution.

Arguably with the Indy 500 though it's the reduction of the wake (size/intensity) from reduced downforce which has meant the slipstream effect is weaker - which means the draft pass is less possible. But you really need aero drag numbers to work that out.