1990's F1 Downforce (confusion)

[Testdrive]

I've got some interesting information from this site in regards to down force.

EG 2300 pounds of downforce at 150MPH, which is about 1000KG for F1 1990's car's

But yesterday, I got conflicting numbers. I think it was Johnathan Palmer link

He stated at Jerez the car's reached 2 tones of downforce. Which I suspect included the car weight. So that in reality is extra 430KG if you include car, driver. I kinda tinker with downforce in a car simulation called Assetto Corsa, the current car F1 car, produces a max down force of like 950KG for full front and rear wing at 150MPH. Yet this becomes problematic at Jerez1988, as I don't have enough grip. I did edit grip levels, by making front and rear wings 2.5x more, but I don't think that is realistic, it did improve the lap times considerably.

But I think there was a limit to down force, Monaco, Jerez, Aida. It's possible its might be this 2 tone limit?. It's either tyres are not good enough or the car realistic is supposed to have more down-force.

I was wondering if anyone knows for certain?

[Greg Locock]

did he say 2 tonnes at 150 mph?

[Testdrive]

did he say 2 tonnes at 150 mph?

Yup, thats what he said at Jerez. He also said the car sitting was half a tone.

[jjn9128]

How does the game work with regards to downforce? A lookup table based on velocity??

[wesley123]

Doesn't he simply mean 2k pounds of downforce? Else he's using metric and imperial measurements in the same sentence.

EDIT; comparing it to GTP/Gr. C cars from that era, they make around 2000+ kgs of downforce at 150mph, so this number could very much be correct
https://www.mulsannescorner.com/aerodat ... TS010.html
https://www.mulsannescorner.com/aerodat ... npt91.html
https://www.mulsannescorner.com/aerodat ... mkiii.html

[Testdrive]

How does the game work with regards to downforce? A lookup table based on velocity??

Here is a test video I did with a few F1 Car Mod's. MP4/5B, Lotus 98T, RSS F1 1990

https://www.youtube.com/channel/UCPxBOg ... nv5yzQQiNA

I'm not sure, but the wings have settings, like 1 to 20. They have coefficients, which has a lift and a drag force.
I guess it calculates the speed and the wing data to create the drag and lift.

You can look at bottom left corner, total drag and lift. Also you can see capability of lift and drag for certain wings and diffuser etc.

[Testdrive]

Doesn't he simply mean 2k pounds of downforce? Else he's using metric and imperial measurements in the same sentence.

EDIT; comparing it to GTP/Gr. C cars from that era, they make around 2000+ kgs of downforce at 150mph, so this number could very much be correct
https://www.mulsannescorner.com/aerodat ... TS010.html
https://www.mulsannescorner.com/aerodat ... npt91.html
https://www.mulsannescorner.com/aerodat ... mkiii.html

Yeah, I think it's correct also. I did some test's this afternoon in Assetto Corsa Car Simulation, I added about about 60% more lift and drag to rear and front wings at Aida for qualifying time of F1 1994. I got very close to the qualifying time. 1.10:800, yet with 60% less drag and lift, times were like 1.15.00's. But this becomes problematic with other track's, where you become like 2 second quicker at like at Interlagos, or 3 seconds slower at Imola88 when you using same top speeds of actual F1 cars. Technically all qualifying times should be very close. It might be an issue with how downforce is applied or how the tyres react to certin down-forces.

[Testdrive]

Doesn't he simply mean 2k pounds of downforce? Else he's using metric and imperial measurements in the same sentence.

EDIT; comparing it to GTP/Gr. C cars from that era, they make around 2000+ kgs of downforce at 150mph, so this number could very much be correct
https://www.mulsannescorner.com/aerodat ... TS010.html
https://www.mulsannescorner.com/aerodat ... npt91.html
https://www.mulsannescorner.com/aerodat ... mkiii.html

He said 2 tonnes, It's probably like this 570 car and driver + 1430KG at 150MHP, I've found numbers from here about 1000KG of downforce for 1990's car, so it's only 430KG off. My tests today seemed to have worked out with this value for a high winged circuit.

[Jolle]

Don’t forget to add the big thumb amount of downforce. Just like the 1500 hp BMW turbo engines. Certainly in period interviews: always double the figures to A: Draw more attention and B: mess with your opponents.

When Hamilton drove the MP4-4 he was surprised by the little downforce it had....

[jjn9128]

Here is a test video I did with a few F1 Car Mod's. MP4/5B, Lotus 98T, RSS F1 1990

https://www.youtube.com/channel/UCPxBOg ... nv5yzQQiNA

I'm not sure, but the wings have settings, like 1 to 20. They have coefficients, which has a lift and a drag force.
I guess it calculates the speed and the wing data to create the drag and lift.

You can look at bottom left corner, total drag and lift. Also you can see capability of lift and drag for certain wings and diffuser etc.

Yeah but what do you mod? What does the file you alter look like? If you put in a coefficient there has to be a frontal area modifier somewhere - otherwise you should be putting in an area coefficient. It seems to be suggesting an angle of attack, so I assume it's shifting downforce by or something!? Similarly there's a GH which I assume is ground height will have some modifier to increase/decrease peak load?!

[Zynerji]

Here is a test video I did with a few F1 Car Mod's. MP4/5B, Lotus 98T, RSS F1 1990

https://www.youtube.com/channel/UCPxBOg ... nv5yzQQiNA

I'm not sure, but the wings have settings, like 1 to 20. They have coefficients, which has a lift and a drag force.
I guess it calculates the speed and the wing data to create the drag and lift.

You can look at bottom left corner, total drag and lift. Also you can see capability of lift and drag for certain wings and diffuser etc.

Yeah but what do you mod? What does the file you alter look like? If you put in a coefficient there has to be a frontal area modifier somewhere - otherwise you should be putting in an area coefficient. It seems to be suggesting an angle of attack, so I assume it's shifting downforce by or something!? Similarly there's a GH which I assume is ground height will have some modifier to increase/decrease peak load?!

I don't believe it actually simulates that deeply. You are speaking as if it is doing some light real-time CFD. I believe its just a LUT category that you fall into depending on what the wings are set to.

I have very little Assetto experience (Xbox only, pc sim was rfactor/rfactor2) so I may be 100% wrong.

[jjn9128]

I don't believe it actually simulates that deeply. You are speaking as if it is doing some light real-time CFD. I believe its just a LUT category that you fall into depending on what the wings are set to.

I have very little Assetto experience (Xbox only, pc sim was rfactor/rfactor2) so I may be 100% wrong.

I wasn't really suggesting CFD in that it's not calculating the flow around the car to give coefficients, but I was assuming a multiplier based on car attitude altering the baseline coefficients - the video they posted seemed to infer that the game was tracking angle of attack and ground clearance.

[Testdrive]

I don't believe it actually simulates that deeply. You are speaking as if it is doing some light real-time CFD. I believe its just a LUT category that you fall into depending on what the wings are set to.

I have very little Assetto experience (Xbox only, pc sim was rfactor/rfactor2) so I may be 100% wrong.

I wasn't really suggesting CFD in that it's not calculating the flow around the car to give coefficients, but I was assuming a multiplier based on car attitude altering the baseline coefficients - the video they posted seemed to infer that the game was tracking angle of attack and ground clearance.

https://www.youtube.com/watch?v=BO7z_si3D4s

Yes it has lut files, each wings setting has coefficients, drag and lift and yes and also height lut to magnifie or decrease and AOA

You can fiddle with CD and CL gains, to reduce or increase, here is an example of from the aero.ini file.

[WING_0]
NAME=front wing
CHORD=1
SPAN=1
POSITION=0, -0.12, 2.4
LUT_AOA_CL= **.lut
LUT_GH_CL=**.lut
CL_GAIN=1.6
LUT_AOA_CD=**.lut
LUT_GH_CD=**.lut
CD_GAIN=1.6
ANGLE=15
ZONE_FRONT_CL=0
ZONE_FRONT_CD=0
ZONE_REAR_CL=0
ZONE_REAR_CD=0
ZONE_LEFT_CL=0.01
ZONE_LEFT_CD=0.01
ZONE_RIGHT_CL=0.01
ZONE_RIGHT_CD=0.01
YAW_CL_GAIN=0.0

[Testdrive]

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne), frontal area = 1,47m2, all values are for ballance conditions of 36% on the front

1989: CL = 2.47, L/D = 2.63
1990: CL = 2.58, L/D = 2.85
1991: CL = 2.72, L/D = 2.97
1992: CL = 3.04, L/D = 3.29
1993: CL = 2.70, L/D = 2.95
1994: CL = 2.63, L/D = 2.62
1995: CL = 2.29, L/D = 2.49
1996: CL = 2.62, L/D = 2.44
1997: CL = 2.75, L/D = 2.42

2.63 CL only generated about 746KG of downforce in my tests. Supposed to be 1065kg. Lift coming from diffuser, rear and front wings. Maybe this includes the car weight also?

[hollus]

You need a frontal area. Real or assumed, but the forces all depend on Cl AND the frontal area plugged in the formula. Is your mod defaulting to 1m2?