Originally Posted by
protc3
Just for a heads up, If you want to check balance of a car on scales, Take the shocks off of the car, Rig up some solid turnbuckles that are all equal in length, and use solid setup wheels in place of the rims and tires. Otherwise all you will be doing is checking the tweak on the car. when you have the shocks on , crank one collar and your weight on that wheel changes. Its not as cut and dry as it seems. Even though the Serpent car has heavier components on one side(Motor), the distance from center highly manipulates the difference of weight. Just think, You take a see saw, place a fat kid towards the center and a thin kid on the seat on the other side. The fat kid wont have the leverage to push the thin kid in the air. Same deal here. The speedo and servo are placed further out from center than the motor. This will counterbalance the motor very well. I Havent checked it but the shock collars are pretty close to even when my ride height is set so that is more than good enough.
I would assume this would be more of a problem on the Durango and the Caster where the ESC is not on the right side of the car. I noticed as well that they ignored the distance from the center line (moment arm) in their line of reasoning. In the Durango's case, it really doesn't matter because the motor is WAY off the center line (it is next to the diff case) and the ESC is in the middle where it can't help balance the car. To do the math correctly, you need to measure the mass of each component along with the distance from the center line to the center of mass of the component( centroid). You could then compile a list someting like this:
I don't own the car so I don't have real numbers for the moment arm distance.
Left:
motor = 341g*30mm = 10571 g-mm
Total Left = 10571 g-mm
Right:
Servo = 56g*32mm = 1792 g-mm
ESC= 80g*45mm = 3600 g-mm
Total Right = 5392 g-mm
The receiver and the two battery packs are balanced about the center. If you want the units to work out to Newtons you have to use kilograms, meters and you have to multiply by 9.8 m/s^2 for gravity. For left to right comparison sake, this is not needed. The distances need to be measured to the center of mass for each part. The motor is easy, it is the middle. The servo and the ESC may not be the center, but it will be close. As it turns out, it probably doesn't matter since the motor appears (from my guessed numbers) to apply much more force on the left side.