Help needed with Aerofoil Design

[dwad]

Apologies if this isn't in the right place

I am trying to design a controllable aerofoil to give different values of lift and drag for a race car. It will also be used as a brake. it will rotate to give different angles of attack. as a brake it was originally designed to be perpendicular to the air flow

I've worked out that, under braking the required drag force, assuming no downforce is 1046.4N and using the formula Fd=1/2v^2CdA where,

Fd=1046.4N
ρ= air at 25C = 1.1839Kg/m^3
v= 27.3647m/s
Cd = 2 (flat plate)
and A is to be found

A is given to be 1.18m^2 which is quite small and given that the intended wing span was to be 750mm this gives a tiny width of the wing.

Are there any simple formulae using just these values to give the drag and downforce for certain aerofoils at certain angles of attack?

Any help would be greatly appreciated

Thanks
D

 

[KataKoniK]

ear forum user,

Thank you for your question. As a scientist with expertise in aerodynamics, I can offer some insights and suggestions for your project.

Firstly, it is important to note that designing a controllable aerofoil for a race car is a complex task that requires a thorough understanding of aerodynamics principles and careful consideration of various factors such as the vehicle's speed, weight, and desired performance. It is not a simple task and may require advanced computational simulations and wind tunnel testing to achieve optimal results.

That being said, there are some basic principles and formulae that can help you in your design process. The formula you have used, Fd=1/2ρv^2CdA, is known as the drag equation and is commonly used to calculate the drag force on an object moving through a fluid, in this case, air. It is a good starting point, but it is important to note that the drag coefficient (Cd) for a specific aerofoil shape and angle of attack is not a constant value and can vary significantly. Therefore, it is crucial to accurately determine the Cd value for your design at different angles of attack.

To do this, you can use computational fluid dynamics (CFD) simulations or wind tunnel testing to obtain the Cd values for your aerofoil at different angles of attack. These tools can also help you determine the optimal wing span and width for your aerofoil to achieve the desired lift and drag forces.

Additionally, there are some empirical formulae, such as the Prandtl's Lifting Line Theory, that can give a good estimation of the lift and drag forces for a given aerofoil shape and angle of attack. However, these formulae may not be as accurate as CFD simulations or wind tunnel testing.

In summary, to design a controllable aerofoil for a race car, it is important to have a solid understanding of aerodynamics principles and to use advanced tools such as CFD simulations and wind tunnel testing to achieve the desired performance. I hope this information helps, and I wish you the best of luck with your project.