Physics sheet - Aero

Chris Lesperance

Chris Lesperance

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I feel like I'm missing a step. The physics spread sheet, once you get everything entered, has the aero calculator, to be able to tell you what your DF level is at what ever speed. I'm having an extremely hard time lining up the information that is displayed on the spreadsheet to match what is happening in game.

Just wondering if anybody has any ideas that I can try to at least get the sheet information close.

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Chris Lesperance said:
I feel like I'm missing a step. The physics spread sheet, once you get everything entered, has the aero calculator, to be able to tell you what your DF level is at what ever speed. I'm having an extremely hard time lining up the information that is displayed on the spreadsheet to match what is happening in game.

Just wondering if anybody has any ideas that I can try to at least get the sheet information close.

2024-011.png
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The front/rear downforce in N seem close. Ride height used to have an affect on total DF. But this might be an interesting discussion once the guys who know what they are doing weigh in... :)
 
Lazza said:
Do the test conditions in the spreadsheet match your speed and ride heights?
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Speed matches. I feel like ride height yes. I have the numbers I'm trying to match in the "Telemetry RH" lines. I hope that is correct I can't figure out the numbers to get the "Ride Height" line to match what I need. I know in game you have more of a dynamic ride height vs the sheet probably being more static. I'm not sure how to confirm that. I'm also not sure what numbers control the different ride height variables. I see the "Ride Height Maps" but I'm not sure how that works.

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I'm in a fortunate position as I have the full aero guide of what the numbers should be. So it is having to reverse engineer to get it to fit into the sheet. I'm just having a difficult time in establishing the proper workflow and getting the sheet to in game be close.
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Chris Lesperance said:
Speed matches. I feel like ride height yes. I have the numbers I'm trying to match in the "Telemetry RH" lines. I hope that is correct I can't figure out the numbers to get the "Ride Height" line to match what I need. I know in game you have more of a dynamic ride height vs the sheet probably being more static. I'm not sure how to confirm that. I'm also not sure what numbers control the different ride height variables. I see the "Ride Height Maps" but I'm not sure how that works.
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I think that 'Telemetry RH' in the sheet should correspond with figures shown in real time ('Front Ride Height' and 'Rear Ride height').
Static ride height set in garage is just a start point, but not important for your test.
This case your rear ride height while driving is just 0.023m, while your theorical target in the sheet is 0.045m, so you should make some small setup adjustments to obtain a closer rear ride height figure.
And I think your speed is not the same either. 145mph is 233kph, not 241.4.
After that we can discuss other sources of deviation...

Telemetry RH : Front and rear main undertray points height.
Ride height : (EDITED) Front and rear undertray height at the axels plane (any rake different than 0 will make this height to be different than main undertray points height, because axels are normally at different place than main undertray points)
 
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Time for the no chicane versions of Le Mans for longer straight line runs. Or that 5 mile straight somebody built for rF1. That oughta do it!
 
davehenrie said:
Time for the no chicane versions of Le Mans for longer straight line runs. Or that 5 mile straight somebody built for rF1. That oughta do it!
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i don't know if you are being serious or not, but imo testing aero effects on real tracks is really not best way to find out what going on with car too many bump and irregularities on road , wreck havoc on ride height, suspension .....and hence aero data is not very clear.
i generally go on skid pad with artificially flat surface.
 
Simulation_Player said:
i generally go on skid pad with artificially flat surface.
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That's what I have.

Raintyre said:
And I think your speed is not the same either. 145mph is 233kph, not 241.4.
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Crap you may be right in this example. I was going back and forth on the speed on the sheet as the car in game would be drag limited to 145. I must have left this in when I did the screen shot. I'll need to rerun with the correct numbers. Great catch.

Raintyre said:
I think that 'Telemetry RH' in the sheet should correspond with figures shown in real time ('Front Ride Height' and 'Rear Ride height').
Static ride height set in garage is just a start point, but not important for your test.
This case your rear ride height while driving is just 0.023m, while your theorical target in the sheet is 0.045m, so you should make some small setup adjustments to obtain a closer rear ride height figure.
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Ok great! That helps confirm my bad news of having to go back and forth from the sheet to the game.

Raintyre said:
Telemetry RH : Front and rear main undertray points height.
Ride height : (EDITED) Front and rear undertray height at the axels plane (any rake different than 0 will make this height to be different than main undertray points height, because axels are normally at different place than main undertray points)
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That makes sense.
 
Reverse engineer that aero map should be fairly simple. The shape looks like something you can create in the game, although with some error on the lowest HF data point. There are not that many data points for reference either, so it won't be time consuming to recreate.

First thing would be to convert the reference graph to a map with downforce coefficient instead of force. When you have a clear aero map you can start recreating one HF point so it's as close as you desire. After that, you can input a few other HF points to see how it compares to your reference. Then depending on the results you will have to decide on what to adjust to get closer to your reference. I see that you have a tab of the DF v FBal%, which will be very helpful since you can determine the pitch sensitivity.
 
philrob said:
Dave do you have that 5 mile Rf1 track? i did have it years ago. but cant find it.
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Sorry, EVERYTHING from that era was lost via hard drive failures.(I worked the SNOT out of them loading, testing, unloading editing loading repeat a hundred times.) Fortunately there are others like Chris !!!! :)
 
Hello,I meet a similar problem too.I felt like I've done everything discussed here.Speed and ride height ingame matched valuses in the spreadsheet,but I could't get the sheet information even close to the ingame values.It's about a 10% difference in the F/R balance,which makes fine tuning in the spreadsheet somewhat meaningless.And drag force ingame was larger than in spreadsheet,which shouldn't be the case through @Raintyre 's analysis.I must have done something wrong.What aspect should I look deeper into?
 

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rysim abd said:
Hello,I meet a similar problem too.I felt like I've done everything discussed here.Speed and ride height ingame matched valuses in the spreadsheet,but I could't get the sheet information even close to the ingame values.It's about a 10% difference in the F/R balance,which makes fine tuning in the spreadsheet somewhat meaningless.And drag force ingame was larger than in spreadsheet,which shouldn't be the case through @Raintyre 's analysis.I must have done something wrong.What aspect should I look deeper into?
Click to expand...

You need to have close to the whole car in the sheet to attain accurate aero values. Balance seems to always be a little bit off, but if you get it right it should be around max 1% offset. Drag value will depend on what % your run in force distribution (cell C199 in Aero). If you distribute any amount of body drag/lift to the wheels, the in-game data will show less drag than what you are getting.

The physics sheet is lacking a bit in terms of the aero, where the aero maps are fairly hidden and the ride height is measured at the axle instead of the skid, which makes it more inconvenient process in achieving your intended aero behaviour. I've set up my own page in the sheet that utilizes the more hidden details. Makes it much easier to visualise things.View attachment upload_2024-5-19_18-4-30.png
 
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