Determined out of the suspension heave signals

The vehicles suspension with its springs and subsequent suspension travel measurements, act as very large load cells. The principle is the same but in a very large scale, which also has advantages not only negatives.

By comparing the heave suspension travel of the model to the real car, and subsequently changing the downforce coefficients of the model, the downforce of the real vehicle can be estimated.

The figures on the right show examples of increasing and decreasing the downforce levels with 6%. We focus on the heave behaviour on the straight.

The approach of LapSim enables to easily analyse the heave behaviour over the complete straight, which significantly increases the accuracy. In addition, one should of course also check if the speeds in the fast corners correlates, as can be seen in figure below.

Looking at the plots on the right, we would state that determining the downforce in this manner has an accuracy of about 3 - 5%, which is often more accurate than getting data out of a wind tunnel, unless it is a 1:1 tunnel.