Analyzing Lift in RAce Studio

(Alex Christie ) #1

Is there any way in race studio to analyze how a kart jacks? There is a gyro right? I’m thinking with some math channels we could maybe see:

Where and how long the kart jacks (maybe an integer function on the Z angle)
How fast if jacks (derivative of z axis angle)
How high (z angle and rear track)

I’ve scrubbed the interwebs and can’t find anything. Any thoughts welcome.

(TJ Koyen) #2

I feel like a much easier way would be to put a GoPro pointing at the rear tire.

Something like this:

(Alex Christie ) #3

Yes. I saw this in my search, good idea. Easier set up but maybe less utility/harder to compare laps.

(TJ Koyen) #4

My opinion would be that there are so many variables to affect lift and there’s no set value as to what the “proper” amount of lift would be, that it would be hard to really compare laps anyway. Track undulations, slight variances in driver inputs, variances of racing line etc. would all affect how much lift you’re getting. Unless you have a glass smooth track and an uber consistent driver, I would think it would be hard to compare when your range is only a few inches of vertical movement.

I think this would be a cool exercise to plot and view on a graph, but in terms of actual usefulness when it comes to tuning a kart I think it’s probably limited. I could be wrong. I would prefer to actually see what the kart is doing with a camera rather than trying to sift through the noise of all the variables on a graph that could affect the lift and rate of lift. Just my thoughts.

(Davin Roberts Sturdivant) #5

@Eric_Gunderson …halp?

(Eric Gunderson) #6

As the mychron is mounted to the steering wheel it’s hard for it to really illustrate lift of the rear end of the kart, which is similar to Andy Schlosser’s comment that the lateral g trace isn’t a true record of lateral g…

Anyway, you can see chassis shake or hopping in that trace which is neat.

I’d say if you really want an accurate illustration of lift, nothing replaces the video or having someone else watch or have someone do lead follow.

Maybe mounting the mychron in another location to experiment?

(James McMahon) #7

I can’t imagine this as being valuable data. Not directly anyway. It’s not necessarily lift you want, it a controlled unloading. Also, bear in mind track surface isn’t perfectly smooth, so you’ll conceiveably observe “lift” when it’s morso the outside front tire “dipping”

You could put a load sensor, perhaps on a bearing carrier to get a trace of force and load transfer.

(Alex Christie ) #8

Thanks for all the input. Given all the effort adjusting how the kart lifts (or unloads), be it mechanical (caster, camber, front track, etc.) or centrifugal (torsion bars, seat struts, rear track, etc.), I was thinking that someone smarter than me would have a clean and simple way to measure and analyze the these changes. But alas, like everything in karting there is no silver bullet.

I did come across a paper where they attached a pressure sensor to the front hubs. If you scroll to the end you can see the vertical and lateral pressure traces of the left and right tires.

(James McMahon) #9

Somewhat related… have you seen the video on “Rate of lift” by Col Fink?

(Thomas Williams) #10

Measuring lift is just measuring ride height. It is easy if you have the money. You will need two. But if you are going to go that far…just get four, and now you can measure chassis twist up to 750 times per second if your DAQ can sample that fast. 1-5V output and 12V supply will wire right into an expansion box on your AIM system. No problem. Just take the delta between left and right ride heights, and divide by the distance between them. Then take the inverse sin. Now you have the angle of the kart frame rails relative to the track…or if you do the 4 sensor option, you do the same calc front and rear…and you can measure chassis twist. Figure $10K and you are in business.

(Alex Christie ) #11

very cool and very pricey. Thanks.

(Eric Riggs) #12

Was kinda thinking of building my own, something like this but probably won’t have the free time this winter: