Formula 1 Aerodynamics – Q&A with Nic Perrin
Some time ago, SimScale hosted a F1 aerodynamics workshop with veteran race engineer Nicolas Perrin, the founder of UK-based motorsports engineering company Perrinn Limited. The company is revolutionizing the racecar design world by creating open source automobiles, helping source new design talent to develop the cars.
In fact, in May 2017, PERRINN confirmed the sale of 2 LMP1 chassis for the 2018 FIA World Endurance Championship and 24 Hours of Le Mans, at a price of £1.2 million ($1.56 million).
In the workshop mentioned above, Nicolas Perrinn gave some great insights into various fascinating aspects of aerodynamics in a race car, explaining the interaction between the front wing and the wheels or how the vortices help to improve the downforce.
The video recording of the full workshop with Perrin is available on YouTube, but we also decided to share some of his advice to you in an easy read. The transcript below includes some of his comments and a Q&A session that followed.
How do you start to design a front wing? Is there any specific part, such as the main plane or the end plate? Do you use the parametric design?(asked by Akrem)
Answer from Nic:
I’m not going to get into details but we start with some sort of sketch. Every single element of the wing comes from it. Every wing element is designed in two dimensions in these sketches. So we effectively define which is going to be the thickness of each element.
With the help of the second image, it is easier to understand: You can see we give parameters everywhere for the thickness and then we just link the lines to create some sort of profiles with curves. Afterward we go into the 3D space.
As you can see, the wing is not purely in two dimensions. It is a swept solid. So it got a defining profile and then it got defining guides. You can observe the guide for the trailing edge and the one for the leading edge. Each element got this.
How does the number of elements and the positioning help to increase the efficiency of a wing in Formula 1 aerodynamics? (asked by Nunez-Milan)
Well, they used to have two elements to start with. Remember that the regulation was written in 2009, therefore 2010 is the second year of the development in this regulation and you always have to start simple and then make it more complex.
What happens is that some areas of the wing need to have more camber and more suction. What I mean by more camber is you increase the load on the wing itself and it is quite clear on the picture of the 2015 car: Near the Y250 vortex, the camber is very high because the chord of the wing is very short. You can imagine each element is very loaded locally. If you only keep two elements, you can not keep the flow attached. And that’s when you start to split more. The same happens in front of the tire; there is a lot of loading going here. Not only vertically, but the wing is going outboard as well.
Where does the term ‘Y250’ come from, that you used when you talking about the front wing? (asked by Joe)
It is very simple. Do you see the location between the ends of the flaps? There is the so-called ‘FIA profile’ in the center. You can’t do anything about it because the FIA wants you to have this profile.
Basically, the distance between the center and the end of it is 250mm. In engineering, when we design the car we talk about Y250 in terms of location.
Would raising the nose increase the flow under the chassis to the underfloor or does it just help to manage vortices at Y250? (asked by Alberto)
The image below visualizes the latest technical regulations. The blue box includes the space we can use to design the car. We designed the nose absolutely to the limit in terms of height.
Raising the nose would decrease the front downforce because there is not such a pressure pushing on the nose. And yes, this would allow more flow in the center of the car under the diffuser. This is a better quality of air going to the back of the car but you will lose front downforce.
What is about shortening the nose? (asked by Alberto)
One of the problems we have is again the regulations: The nose has to be under the blue line and needs to have a minimum thickness. For security reasons, a crash test has to be performed. So you can imagine that the underside of the nose is very close to the FIA section under it.
This is a problem because the air going into this small gap will separate. If you make the nose shorter you don’t have a nose over the FIA section and that will reduce the problems. But on the other hand, it is more difficult to pass the crash test with a short nose.
SimScale is currently being used by the team for simulation and Onshape for CAD, as part of Perrinn Limited’ software stack.