Quote:
Originally Posted by Samurai A complex equation need not be constantly linear or non-linear. What about torque curve or power curve? Is it constantly linear or non-linear? Nope, it isn't.
Am I guessing all this? No! I drew a graph based on my observation, and Arka has agreed that is correct in principle. And he is a master artisan when it comes to Jeeps. |
Samurai, you are right, a complex equation need not be constantly linear or non linear, so is the torque and power curve which is derived from lots of variables which keep on changing.
Since the master artisan has already spoken, poor me will try and speak a few things, May I??
Ok, I will first explain in simpler terms then complicate it with a free body diagram followed by resolving the forces about a point (considering the system to be in equilibrium).
For a layman- There are four forces which play a role here:-
1. Weight of the vehicle
2. Force due to lateral acceleration (read Rolling in off-road parlance)
3. Height of Center of gravity (C.G.)
4. Wheel track
On a banked vehicle these forces resolve into various horizontal and vertical forces but basically the forces remain the same (only these 4). So if you change all these the amount of weight transfer will change; in other words the nature and type of suspension does not determine how much weight is getting transferred to the inner and outer wheels it is only these 4 and not the spring rates and roll stiffness.
For others (
even Gurus can also read this):-
On a flat road the forces acting (laterally are) represented like this-
Unless there is a lateral acceleration (read Rolling in off-road parlance) it has only a static component of the total forces, once it starts tilting ( read Rolling in off-road parlance) there is an additional component of force called as dynamic component. The amount of weight on the wheels is dependent only on these two components namely Static and Dynamic. The representation is as shown below:-
This shows one wheel looses weight and another gains weight, OK Sam ??
Next consider a situation where the vehicle is banked / articulated (read Rolling in off-road parlance), here the force components remain the same but they get resolved in accordance to the roll angle (phi). See this pic:-
The resolved forces turn out like this:-
Now can someone tell me if there is any term which mentions about spring and suspension stiffness? NO! So what I had been harping continuously was correct, the graph is wrong. Since no terms related to suspension feature in these equations, there is no relation between Suspension characteristics and the amount of weight transfer when on road and off- road. Weight transfer-> CG Shifting
Hence Proved.
Lets take it one step further can anyone tell me when the vehicle will begin to roll over? (I am not trying to ridicule anyone, I just want people to know what the truth is, contrary to what is being told here)
Quote:
Originally Posted by '72 Bullet Hey spike,
Please explain why the spring rates and roll stiffness would not play any role in a "roll".
I think that as the CoG starts shifting, the suspension will try and push it back/resisting (layman terms, sorry) and hence the spring rates and roll stiffness is relevant.
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Dear 72 Bullet, poor me has tried to explain with whatever limited knowledge I had, now it is up to the Gurus and Jeep Gods to approve. Please let me know if you are OK with the explanation, otherwise I will explain in more detail. I had to use pictures and equations otherwise people will again get a reason to crib that all these were framed.
This is my last post on this thread, I think I have had enough, no point in breaking my head. I rest my case here. :-)
Spike Arrestor
PS- Arka, regarding vehicle toppling at the "Robinson Point" (pardon me Robi, I have to be specific), it had nothing to do with articulation. I was keeping quiet on this as it would hurt others sentiments, as I am being questioned, I have to answer this. It was purely driver error, I did not see it but I have Eye witness account on this. The eye witness is a very Senior, experienced and respected Jeeper in Indian offroading scene
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