Відео

Here is the math channel that you can use to get the half circle for 1.5 Gs. You can change it for whatever G number you want. sqrt(1.5^2-Lateral Accel^2). However, in RS3 Analysis you can choose to add friction circle lines to a scatter plot. If you aren't using RS3 Analysis yet, I recommend making the switch. Ray

@@precisiondrivinganalytics already using Rs3 but didn’t know about the circle lines, thank you for the tip and mostly thank you for the effort to make this content and the effort to answer !

Speed and lateral G’s are part of the formula when calculating the theoretical amount of steering required to get around a corner. The calculation isn’t perfect but it is good enough to determine what is happening.

​@@precisiondrivinganalytics I'm referring to the graph shown at 5 mins into the video, which has only Steering Angle and Ay, no additional formulas are mentioned

@gattopazzo80 Ok, got it. That is more of a broad stroke approach that relies on the premise that if steering is increasing but lateral G's aren't increasing than that is understeer. If steering is decreasing and lateral G's are remaining the same or decreasing than that is oversteer. I usually take speed into account by using speed as a color channel if the software allows it. But you are correct, identifying the understeer in slow corners is easier because there is more steering input and the car is also staying in that slow corner longer so it is easier to tell what the Lateral G's are doing. Zooming into a particular corner does make it a little easier to identify as well.

Thanks John! It was great working with you as well!!

There is always something to learn! Glad you liked it!

I don't think so because we have run these cars at much higher temperatures than this and although there can be a loss of grip, it is a consistent loss of grip and not something that happens out of the blue.

Hi Ian, I’m not sure what it was. The Steering At The Wheels math channel is simply the steering angle divided by the steering ratio. My best guess is that someone put fluid down before the access road but it is possible that a toe link broke or there was some other mechanical issue. Due to the amount of crash damage, it was hard for the mechanics to tell if there was a mechanical issue. And yes, the tire pressures were normal.

More downforce would mean more G forces so the loads would increase.

Great stuff as usual Ray. If you know the weight of the car can you correlate this to pounds of pressure on the tires?

@@HiPoDriver I don’t think so. This is using changes in G Forces to estimate the changes in tire load. As the load increases on one tire, it decreases on another tire. I’m saying load here but it is really g forces. There is obviously a correlation though. To accurately calculate true load on each tire, shock pots, spring rates, motion ratios, etc. are needed.

Hi Justin, yes, ideally this graph would be linear. That would indicate a perfectly neutral car. But that rarely happens. If I see the graph being perfectly linear then my first question is whether the driver is pushing hard enough. I think every car needs at least a small amount of understeer in order for the driver to have the confidence that he/she needs to push. Small amounts of oversteer are fine as well as long as the driver has the confidence to handle it.

@@precisiondrivinganalytics I actually tried out this channel for some data of my schools Formula SAE car, and it was very interesting seeing how large of a slope the plot was( almost 1:1) along with very heavy understeer segments. Leads me to believe it is a combination of a natural entry to mid corner understeer as well as drivers not working the back end of the car hard enough. Thoughts?

@@justintrammell5274 this chart is more of a big picture overview of what the driver is dealing with in regards to car's handling. The understeer can be induced/aggravated by the driver or the car may be in need of a setup change. Although you can zoom in on where the understeer starts, it really isn't precise enough to be making a lot of assumptions about setup and how the driver is driving the car. However, if the understeer keeps building to a very high level with more steering input then that can certainly mean that the driver is trying to provide too much steering input. The friction circle is a much better way to determine whether or not the driver is maximizing the grip level of the tire. Good driver feedback is essential in determining where to go with setup. He/she needs to be able to say what the car is doing at corner entry, mid corner, and exit. However, there is a way to come up with a rough calculation of understeer and oversteer and this is a great tool for validating the driver's feedback and helping to determine the path to take in regards to setup. Email me at rphillips@drivinganalytics.com if you want to find out more about that.

Hi Melissa, glad you liked my video. I'm assuming you are talking AIM because I have had this happen to me before as well. Save the profile that you are working on, open another profile, and then come back to the one that you were creating. It's not logical but that has worked for me. Cheers, Ray