Anti squat calculator for rc?
#1

Does one exist? I've seen 4 link calculators for cars, but I've never seen and cannot find any video that tells you exactly how to calculate your anti squat percentage on say, a 2wd buggy.
Does it exist?
Does it exist?
#2

Not that I know of, maybe RC Crew Chief.
Normally anti-squat is pre-determined by pill inserts nowadays and a lookup chart/table in the manual.
Anti-squat is measured in degrees.
Normally anti-squat is pre-determined by pill inserts nowadays and a lookup chart/table in the manual.
Anti-squat is measured in degrees.
#3

Yeah.. that doesn't actually tell you anything, heh. That's the annoying part. There's calculations to get an actual anti squat value... and degrees on pills is a scratch on the surface.
#4

Looks to me if you have a full size calculator it can be used on a scale model as wel.
I know there is a calculator called SUSPROG to calculate and simulate suspensions.
I know there is a calculator called SUSPROG to calculate and simulate suspensions.
#5
Tech Apprentice

Yes. The same guys that make So Dialed app makes a pill Calculator app.
#7

Rc crew chief sounds like it might do what I'm looking for.. but you have to pay for it. I was hoping there would be a suspension guru on here that knew the calculations, that could just easily tell my how to classify the rear for spit? Susprog could probably do it, but looking for something rc related.. and that one is super expensive lol
Again, pills don't tell you anti squat.. They're just one piece in a complex puzzle.
Again, pills don't tell you anti squat.. They're just one piece in a complex puzzle.
#8
Tech Initiate

Antisquat is calculated off of your sprung mass center of gravity height. So its both active and different from brand to brand. Even in full scale cars it’s difficult to calculate without lots of CAD modeling or an elaborate weighing process. What are you trying to gain by getting an actual percentage?
#9

I don't understand exactly what you are looking for.... Anti-squat is a relatively simple concept.
What exactly are you trying to calculate?
What exactly are you trying to calculate?
#10

Well real cars need more precise adjustments, and have more ability to change singular aspects of the setup.
RC cars are much smaller so some aspects can't be adjusted. Also its quite different from solid axle dynamics so its not going to be the same anyway.
In my racing experience simply adjusting within the range given on modern cars is plenty effective enough for anything you need to do.
RC cars are much smaller so some aspects can't be adjusted. Also its quite different from solid axle dynamics so its not going to be the same anyway.
In my racing experience simply adjusting within the range given on modern cars is plenty effective enough for anything you need to do.
#11

Well real cars need more precise adjustments, and have more ability to change singular aspects of the setup.
RC cars are much smaller so some aspects can't be adjusted. Also its quite different from solid axle dynamics so its not going to be the same anyway.
In my racing experience simply adjusting within the range given on modern cars is plenty effective enough for anything you need to do.
RC cars are much smaller so some aspects can't be adjusted. Also its quite different from solid axle dynamics so its not going to be the same anyway.
In my racing experience simply adjusting within the range given on modern cars is plenty effective enough for anything you need to do.
#12
Tech Initiate

To be clear… you’re trying to compare the antisquat percentage (definitive number) of a 4-link solid axle setup to an a-arm configurations percentage?
#13

#14

With an independent suspension rear wheel drive car, you basically draw a line from the ground contact point of the rear tyre at the same angle as the anti-squat angle of the rear arms. You then compare the height of this line at the centre of gravity of the car with the height of the centre of gravity. The ratio of the height of the 'line of force' to the height of the centre of gravity gives you percentage of anti-squat. If there is no squat built into the suspension, the line follows along the ground giving 0% squat. If the line angles up steep enough to meet the centre of gravity, you get 100% anti-squat.
If you want to calculate it, you can use the following simple equation:
Anti-squat percentage = Anti-squat force height @ cg / centre of gravity height x 100
= [anti-squat angle x 3.14/180 x wheelbase x Frt weight bias / Centre of gravity Height] x 100
Anti-squat force height at cg = (distance from rear tyres to centre of gravity x position) x sin (anti-squat angle)
distance from rear tyres to centre of gravity x position= (weight distribution frt %) x wheelbase
sin (anti-squat angle) = anti-squat angle x 3.14/180 (using radian conversion for small angles)
Using some typical values for a B6.3:
Cg height = 45mm
Wheelbase = 280mm
Weight Bias = 40% front
Anti-squat = 2 deg
-> 8.6% of anti-squat.
Hope this helps.
Ray
#15

Great stuff Ray. Thanks for take a couple minutes to educate us.
This is what the forums are for. Not the "you shouldn't do this, you shouldn't do that". It's for "this is how this works, learn, utilize, create".
This is what the forums are for. Not the "you shouldn't do this, you shouldn't do that". It's for "this is how this works, learn, utilize, create".