Ackerman Vector

If you want to get serious about RC, you are going to have to immerse yourself in some of the terminology. The Ackerman Vector is covered here.

Since the invention of the wheel and the first use of wagons and carts, the steering arms were parallel to each other. This created certain steering problems, but for the most part wagons moved slowly and the steering difficulties were tolerated. Around the beginning of the 19th century, a man named Rudolf Ackerman worked out a solution using vectored steering arms. The resulting principles have impacted race cars, go karts, and even the steering of RC models.

Ackerman is now used as a term to describe the steering geometry that causes the inside front wheel to turn tighter than the outside front wheel. This allows all four wheels to basically roll around a common point during a turn. It is necessary to view a diagram to see the Ackerman Vector. With the use of a diagram, you can see that on an oval track, the inside front tire must turn a larger number of degrees than the outside front tire to achieve true Ackerman steering.

Many people refer to Ackerman Vectors as toe-in and toe-out. Toe-in and toe-out refers to the position of the wheel during a turn relative to a line marking the true circumference of the turning circle. When the wheel is toe-in, it is trying to turn in a sharper circle than the true circumference. When the wheel is toe-out it is trying to turn in a wider circle than the true circumference.

This is often termed true Ackerman, more Ackerman, or less Ackerman. The terms refer to how far the wheel vectors are off from true Ackerman steering geometry. The wheel vectors are set by how the steering arms are located and vectored. RC racing fans have made use of Ackerman steering geometry to improve the turning performance of their models. There are other factors concerned with improved traction in high speed turning such as slip vector. Although there are plenty of guides available that give advice on proper steering arm position, trial and error is often the best way of determining the proper vectors for an individual model.

Ackerman vectors are important in full sized racing cars and go karts. It is a reflection of the increased complexity of RC models and the highly competitive nature of RC racing that they have become of such interest to hobbyist as well. The person who still views RC operation and racing as merely pressing a button and operating a controller will quickly learn that construct methods and proper set up are as important here as at any other race track regardless of its size.