FIRST PRINCIPLES DANNY BOY
How to establish a test programme
What should you really be considering when you’re testing? By Danny Nowlan
also as a simulation engineer and developer, so feel that I am in a pretty unique position to offer a perspective. In a lot of cases I have only had track data to work with and, if you’re smart, you can get quite a bit out of this. The purpose of this article is to share with you the lessons I have learned from this and outline what I consider to be some important boxes you need to tick when establishing a test programme for yourself. I also want to outline some of the pitfalls you should try and avoid when preparing for an upcoming season. Too often I have seen people
H
ow should you go about testing? I’ve worked both as a race and data engineer, and
sorting through data that tells them nothing whatsoever about the car. The two biggest traps that people fall into are: 1) You get so wrapped up in
topping the timesheets during testing that you forget to run the car through a number of different set up options to build a complete picture of what the car is actually doing. The corollary of this is that if everyone does this and the car is really weird, you wind up in an engineering dead end. 2) You spend a fortune on test
programmes that are completely useless and give you very little real and tangible information about the car’s capability. We are going to see that if you
do a little bit of forward planning, you can actually tell quite a bit about the car from the data you
amass. The first step, believe it or
not, is to read the racecar manual and / or measure up the racecar, then determine the downforce the car is running. Most racecar manufacturers should give you some indication of the level of downforce, but if you don’t have this you can always approximate it from the data. I am going to talk about this in great detail shortly, but initially you want rough ballpark figures of downforce (CLA), drag (CDA) and aero balance. Once you have an idea of the
aero, your next goal is to come up with a rough approximation of the range of lateral load transfer distributions you are going to deal with. For this you need to know your suspension geometry and your different combinations of springs
and bars. This will give you a rough idea of the load envelope of the tyre you need to be testing on. Effectively, what you are looking for is to populate a spreadsheet that looks like table 1, shown right. You don’t have to reproduce
table 1 in its entirety, but it gives you a tool that tells you all the possible tyre load situations, and this will tell you what to try when you test your tyres. We will discuss this in detail shortly. The next step in this process is to
calibrate your sensors properly. This might sound an incredibly obvious thing to say, but I have seen testing reduced to nothing because the data acquisition system wasn’t taken care of properly.
Make no mistake, this is a critical area on any racecar and you have to stay on top of it. There are no
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www.racecarengineering.com • August 2011 65
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