Calculating The Frontal Area Of A Racing Car
You need the frontal area of a racing car for your calculations but you do not know it! And no amount of Googling has enabled you to find it either. What can you do?
This article presents a simple 8-step method you can use to approximate your racing cars frontal area.
Want the handout?
If you add your email address below I will send you an 11-page slide deck to walk through this at your own pace. Also included is a handy transparent grid template overlay, that will get you going with your own racing car super quickly.
What You Will Need
- The width of your racing car
- The height of your racing car
- A picture of the front of your car (or camera to take one)
- A presentation software (e.g. PowerPoint)
- A transparent grid template (subscribers grab yours in the handout deck)
Step 1: Measure Your Racing Car
What you need is the maximum width and the maximum height of your racing car.
In my example, the race cars width is 1.61m and the height is 1.07m.
Step 2: Select Image
For this to work, you need a good frontal image of your racing car. This can be surprisingly hard to find. If you do not have one to hand, then it is best if you go and take one.
The above image is what I decided to use for this article. Whilst it is not absolutely ideal, because the car is in roll, it is good enough.
The reason I chose this one is because:
- the image is reasonably high resolution
- it is nearly a perfect head-on shot
- it was taken from a reasonably long way away*
*The distance means that any distortion, caused by the camera lens, is minimised. The image is fairly “flat” which means it is better to measure off.
Step 3: Overlay & Align Transparent Grid
Given my race car is in roll, I needed to align the grid to the car in the image. You can see this above.
Interestingly I struggled to find a good quality transparent grid to overlay. I made the one you see which you can get for free in the handout.
The overlaying I am doing in PowerPoint but you could use any similar software.
Step 4: Outline Your Racing Car
One of the reasons I choose to use PowerPoint is that the current versions have a “Draw” capability.
Hopefully you can see that I was able to outline the racing car in red in the image above.
You might want to do this more precisely, i.e. closer to the car, but I did it a bit more rough so you could see it more clearly for this article.
Step 5: Calculate Total Area
In the image above you can see that I have removed the racing car image. This helps minimise distractions and hopefully makes the concept of what I am trying to explain clearer. You might be OK with leaving your racecar in the background, but I find this easier to see.
The aim of the exercise is to calculate the area of what is now the racing cars silhouette.
The first calculation is the area of a rectangle that surrounds the whole car.
What you do is calculate the total area that would completely cover the racing car.
In this example my racing car is 1.61m wide and 1.07m high. To calculate the area of that box you multiply these two together:
1.61m x 1.07m = 1.73m^2
Step 6: Calculate The Total No. of Squares
The design of the transparent grid overlay helps here. In my case, you can easily see groups of 5 squares – like nice graph paper.
In each mini group you can see there are:
5 x 5 = 25 squares.
The are 6 along the bottom and 4 up the side.
In total therefore there are:
6 x 4 x 25 = 600 squares.
Step 7: Calculate Squares Covering Race Car
You could try counting up all the squares that are covered by the racing car. Alternatively, there is less counting to do 😎 if you instead count the squares that are NOT covered by the silhouette. Then take that number away from the total number of squares just worked out in Step 6.
In the image above you can see how I did this, by counting the yellow boxes. There were a couple of nice boxes of 25 squares. Then a box of 20. After that, it was a case of counting each individual whole square. For the squares that were not complete, I just approximated. Again, I took a bit of artistic license here but you could be more accurate if you like.
The total squares I counted that were not contained in the silhouette were: 135 squares.
This means the race car takes up:
600 – 135 = 465 squares.
Step 8: Calculate Frontal Area Of The Racing Car
Now you know the total number of squares (600) and the total number covering the racing car (465). You also know the total area of the rectangle covering the race car (1.73m^2)
By multiplying the proportion of squares covered by the total area, you can find your racing cars actual frontal area (or at least a good approximation.)
Proportion squares covered by race car: 465 / 600 = 0.775 –> 77.5%
From this you can now calculate your racing cars frontal area:
Frontal Area of race car: 77.5% * 1.73m^2 = 1.34m^2
Personally, I found the most time-consuming part of this process was finding a decent image of the race car. This is because most images are at an angle to make them look better!
Once you have that though, hopefully, you can easily follow along with these steps to quickly calculate a racing cars frontal area.
Hope this helps you and don’t forget to grab the free handout if you’d like the transparent grid to get you going.
Apply this calculation in your gear ratio optimisation –> https://www.staging41.yourdatadriven.com/how-to-use-the-gearing-optimisation-spreadsheet/
Optimise your tyre temperatures (inc FREE spreadsheet) –> https://www.staging41.yourdatadriven.com/guide-to-interpreting-tyre-temperatures-in-motorsports/
Starting with datalogging? Learn about this key data channel –> https://www.staging41.yourdatadriven.com/introduction-to-motorsport-data-analysis-delta-t/