F1 Wing lift (downforce)

[zakfourie]

I was wondering...does anyone know what the
lift coefficient of a F1 rear wing is?
And what the maximum lift coefficient will be round about of a 2 element wing?
The Lift (downforce) equation is defined by:

L = 0.5 x rho x CL x A x V^2

And I'm after that CL - the lift coefficient.


reason why I'm asking is because I'm responsible for the aerodynamics
of our prototype Formula SAE/student car.
Don't wanna bore you with the facts feel free to ask if you're interested about that details...

[Matt Pratola]

I don't know, but I would suspect that the CL on the car and off the car might be quite different, as they are designing to optimize the entire package. For your FSAE team, more likely it is only reasonable to optimize each individual component independently. Also, at the speeds you guys run, are you still at laminar flow? The F1 wings might actually be quite poor at those speeds, simply because they are optimizing for different speeds and running conditions.

What have you guys started with, some NACA profiles?

Hope you post some pics of the build as it goes! (or after the competition - that would be completely understandable!)

[Wingman]

Hi Zak

Matt is right that you shouldn't be comparing a FSAE car to F1, I haven't run in Formula student, but I understand it's all about handling tests, so efficiency is less important than maximum downforce. I have seen pictures of huge, multi element very highly cambered front and rear wings.

I would recommend a sectional design program like xfoil (although this is the free version and can only do single elements): optimise in fully turbulent mode at a relevant speed and check in laminar mode (you would be lucky if you can buuld a wing that can maintain laminar flow) and with fixed transition at a couple of chordwise stations to check the wing is robust - the last thing you need in a handling test is a wing giving up performance under high loading conditions, and the wing will always perform worse on the car than in free air. A few words of warning, if at all possible mount the wing from the upper (positive pressure) surface, the detail design of pillar/pylon mounts takes days of CFD resource, and blockage below the wing will always cost performance.

Peter

[Matt Pratola]

Out of curiosity, what do you do Peter?

-Matt

[zakfourie]

I don't know, but I would suspect that the CL on the car and off the car might be quite different, as they are designing to optimize the entire package. For your FSAE team, more likely it is only reasonable to optimize each individual component independently. Also, at the speeds you guys run, are you still at laminar flow? The F1 wings might actually be quite poor at those speeds, simply because they are optimizing for different speeds and running conditions.

What have you guys started with, some NACA profiles?

Hope you post some pics of the build as it goes! (or after the competition - that would be completely understandable!)

We haven't started with any profiles yet since I am still trying to figure out the which C_L factor would give me the the best downforce, either with double or multi element wings. The low speeds is a problem I know. But according to a simple simulation that I wrote in EES and Excel, it will still help in terms of time. That is why I'm after a good C_L factor for maximum downforce at these speeds. Drag won't be a issue here though.

Hi Zak

Matt is right that you shouldn't be comparing a FSAE car to F1, I haven't run in Formula student, but I understand it's all about handling tests, so efficiency is less important than maximum downforce. I have seen pictures of huge, multi element very highly cambered front and rear wings.

I would recommend a sectional design program like xfoil (although this is the free version and can only do single elements): optimise in fully turbulent mode at a relevant speed and check in laminar mode (you would be lucky if you can buuld a wing that can maintain laminar flow) and with fixed transition at a couple of chordwise stations to check the wing is robust - the last thing you need in a handling test is a wing giving up performance under high loading conditions, and the wing will always perform worse on the car than in free air. A few words of warning, if at all possible mount the wing from the upper (positive pressure) surface, the detail design of pillar/pylon mounts takes days of CFD resource, and blockage below the wing will always cost performance.

Peter

No I didn't compare a FSAE car to a F1 car

People who designed the JS1 glider's (the best glider in its class) said to me that
the maximum C_L that can be achieved is about 2.5 for a double element. Which I think is good but not unbeatable.
That is why I want to know the range that a F1 wing can achieve if the airfoil is highly cambered and at a high angle of attack. (or rather its aerodynamicists)

[Ken]

Zak Pm with your email details I have a lot of stuff with regard to aerofoils also the formulea for the Cl and lift /drag relationships and can supply you with the co-ords for many different wing sections which you miight find usefull.

Just on a side note though, I think you may be approaching your project from the wrong direction. Having been up close to F1's with an aerodynamicist from Shorts/ Bombardier his belief is that car wings are generating way more down force than any airloil could generate in lift. Mainly due to the small areas involved and with multiple elements there would be too much interfernce for car wings to work on lift components only.

He reasons that the "wings" are no more than streamlined vanes. If you examine the photographs or the actual wings upclose. Also if you follow the the articles I send to you you will see the wings on the cars are being forced to work beyond the stall angle (angle of attack is too great ), that causes the airflow to seperate far to soon thus rendering the airfoil inefficient in terms of pure lift.

I wish you all success in your venture and hope the material I send sheds light upon your project.

My aerodynamic knowledge comes from designing high level competition model planes for racing, pattern flying and gliding. The extracts I am sending you are from my "Bible" which along with my friend have proven to be reliable sources of info

[zakfourie]

Thanx Ken appreciate it alot!