Demo of effect of Roll Centre changes on Camber and Camber Gain. Visit the RC Crew Chief Website www.wrightdesign.rccrewchief.ca for more details. @RCCrewChief
Hello, Very nice video! How do you go about adjusting roll center, camber gain, etc. using a Pillowball style frontend? Do you offer Arrma 1/7 Car or 1/8 Buggy models in your library? Cheers
Adjustability needs to be built into the suspension to allow for roll center and camber adjustments. For pillowball suspension you would need to be able to adjust the position of the inner pivot point of the lower/upper control arm. I do not have models for the chassis you mentioned but you can create your own models by accurately measuring the suspension geometry. There are videos on the website that go through this process. The program has a 30 day trial period if you want to give it a try.
Don't think I agree with that approach. This is a setup program so you want to see what the camber is under race conditions. It's lateral g acting on the sprung mass that induces chassis roll so just looking at roll angle doesn't tell you anything about what is actually causing the roll. The program takes into account everything that affects chassis roll, roll stiffness, Kinematic Roll Centre, sprung mass CG, and droop so the input is lateral g and the output is chassis roll. Cause and effect. In reality the relationship between lateral g and roll angle is fairly linear for all the on road cars I have looked at as the chassis roll angles are very small, generally only 2-3 deg. One of the graphs you can plot is roll angle versus lateral g if you want to investigate it further.
What I was trying to illustrate is there are a number of different ways to achieve as similar result. The optimal camber gain would be a function of the tire itself and the racing surface.
Interesting. Lateral g is a function of vehicle sprung and unsprung mass and tire force acting at the deformed contact patch. This lateral force is defined by the tire slip angle and friction coefficient. These tire dynamics would need to account for pacejka tire coefficients, or similar modeling. I suppose extrapolating to kinematic equations from empirical data could be used.
Also, as lateral g increases, so does tire deflection and upright deflection. This in turn induces positive camber. A quick search on fsae compliance illustrates this behavior.
BurnDuration If you are asking can the program predict the ultimate g limit then no it cannot because we do not have tire data for vertical versus lateral force at different camber, slip angles, temperatures, surfaces ...... It is unlikely we ever will. I could assume a tire model but that is a huge assumption. So what the program does is treat the tires as a constant and look at the kinematics. In simple terms the lateral g is applied at the sprung and unsprung mass CG and the springs and Anti-roll bars resist the applied force. The amount of chassis roll is calculated from that force balance. I know the maximum g achieved in a TC is around 2g (max spike I have recorded is 2.5g) so that is the value I use to look a camber angles. The method used in the program is that presented in Race Car Vehicle Dynamics by Milliken & Milliken.
So when you say camber gain you mean going from -3 camber to -.4 camber that is considered a camber gain, right? It's confusing because when people say run more camber usually they mean run more - camber. Am I understanding this correctly? A camber loss would mean that upon roll negative camber is actually increased? And a camber gain negative camber is decreased to reach -.4 degrees of camber. Also how should camber change when compressing the suspension totally vertically versus rolling laterally? It seems like most cars have more negative camber with vertical suspension compression but when you introduce lateral movement in addition to one side of the suspension compressing you lose negative camber. Please fill me in on what is meant by camber gain and these different relationships should. Negative camber increase or decrease under compression and under roll. Thank you
There are two parameters regarding camber. Static camber which is what you set on your car sitting on the ground (or desk) and camber gain which affects the camber as the suspension moves. When the chassis rolls the outside tire will lose camber. The more camber gain you have the less the tire camber will change as the chassis rolls. The amount of camber gain required is a function of the tire construction. If you watch this video starting at around time 11:45 it may help to clarify it. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wAXdzbW8WP4.html
RCCrewChief Thank you! I understand static and camber gain but I was beginning to be confused by people because I wasn't sure if they were saying they gain camber when the car rolls because I know you loose camber then, and then if you think about technically camber is negative in our application so camber gain could mean going less negative or loosing camber so I just wanted to make sure. With my cars I see little to no camber gain under vertical compression even with a relatively short link. It seems like with a lower roll center positioned camber link you get less camber gain? Assuming the same link length. But with a higher position roll center link you get more camber gain? Wish it was the opposite.
Lyons Camber gain is used to keep camber loss during chassis roll to a minimum. They call it gain, because you always lose camber, but lose less when you have gain built into the set up.
I have one 5th scale on road model. If you install RC3 I can send you the model and you can import it and take it for a test drive. There is a 30 day free trial period.
@@RCCrewChief can you go in and do like a save as to a car and give the arms different lengths and your software be ok with that ? I could then open up your 1/5 scale or even a 1/10 scale that had about the same chassis adjustment points save as my car and put in my a arm lengths chassis hieght wheel offset etc.. ?
You would be better off starting with the model that is already done. Creating a model is something you should try after becoming familiar with the program.
