RC Car Action - July 2013

5Remove your 4X4’s teering servo and install it in the LCG chassis.

6Remove the stock 4X4 servo horn and replace it with the conversion kit part. Install the LCG servo horn so it points up, rather than to the right as in the 4X4. Power up your radio gear and make certain the horn points straight up with the steering wheel at neutral..

Install the servo horn so it points straight up. Not that the linkage ball has a “tall” side, but install the linkage with the ball facing up, as shown.

7Install the LCG steering linkage onto the servo horn. ;e “dogleg” end attaches to the horn

8Remove the steering bellcranks. First, take out the screws that secure the ‘cranks. Next, slide them o; the steering posts.

TIP Don’t be surprised if the lower bellcrank bearings pop out and stay on the posts. ;is is normal. To remove the bearings, use a pair of pliers as an anvil and tap the posts through the bearings using a screwdriver handle. Close the pliers just enough to prevent the bearing from passing through while allowing the post to slip through untouched.

THE BENEFIT OF LOW;CG

Why does lowering a vehicle’s center of gravity improve handling? If we exaggerate our examples of low CG and high CG to absurdity, it’s easy to visualize how lower is better—consider a racing kart versus a “racing” barstool. Obviously, the kart is going to get around the track with a lot more speed (the barstool, however, will get around the track with a lot more laughs).

If you want to get all science-y about it, the height of a car’s center of gravity can be thought of as a lever that pushes the car to the outside of the turn. ;e higher the CG, the longer the lever.

As you push against the lever, weight transfers from the inside tires to the outside tires. Push hard enough, and the inside tires will become completely unweighted, leaving the ground entirely. It’s pretty easy to imagine this happening to Barry Stoole as he rolls his barstool over in turn one.

Now, let’s consider Karl Kart, who has a CG located at about the height of his spleen. If you shove Karl at his CG, you might be able to slide him sideways, but it’s highly unlikely that you’ll tip him over.

Here’s a more scientific look at CG height in action with exaggerated motor and battery positions. Imagine both cars taking the same corner at the same speed. ;e car on the right has a lower CG and transfers weight across its tires more evenly while cornering. ;is allows it to have more traction and maintain more speed through the turn. ;e car on the right has a higher CG and transfers more weight to the outside tires, reducing traction. It can’t hold the speed of its low-CG counterpart without losing traction, or if the CG is really high, flipping right o; the track.

If he can hang on tight enough to not fly o ;, Mr. Stoole’s motorized bar stool will likely tip over the first time he turns the front wheels.

Mr. Kart, on the other hand, isn’t going anywhere. ;e low CG of the chassis and driving position will keep all four tires planted firmly on the ground.