Perrin

[MadMatt]

There are actually download links but they dont work, the f1 car is CAD, but the stl is fine for now, id pay 40 pounds for the lmp stl alone lol,...

Yes, even for a school project I think it is quite cool to have such a detailed model on hand. Wish my Uni was into this, that would have led to interesting student projects although with my new job I might work on that!

[silente]

are you going to work on a perrinn car in 2015? and, in anycase, on an LMP?

in case, congratulations! lucky you!

I wrote to Nicolas to ask about data sharing, let's see what he replies.

You have any idea about which kind of correlation your results could have to real world measurement/wind tunnel testing?

[MadMatt]

are you going to work on a perrinn car in 2015? and, in anycase, on an LMP?

in case, congratulations! lucky you!

I wrote to Nicolas to ask about data sharing, let's see what he replies.

You have any idea about which kind of correlation your results could have to real world measurement/wind tunnel testing?

Nono I'm not gonna work on that project! I meant that I because I my job, I might get students involved in some kind of LMP1 "virtual" project (like KVRC) as a coursework, I am now a research assistant in an Uni.

First, I must say that the results I will get are going to be quite different even from Nicolas' results, because I am not going to model porous media, engine intake needs, exhaust gas, and other secondary fluids. It will just be a pure external CFD simulation, so all these flat surfaces will really lower the performance of the car, but it would take me too long to work on the .STL file that I have got to separate parts and do all this.

However, I will be able to compare his model to my KVRC 2015 model.

[andylaurence]

STEP files were previously available. What's on the server access has varied over time.

[silente]

Nicolas replied to me and, as far as i understood, i think he doesn't mind us sharing this info.

The data he communicated are in the region of 0.75 for CdA and 3.4 for ClA. Balance is in the region of 43.5%. These values refer of course to a certain set of ride heights, i didn't receive anything from him about ride height/pitch sensitivity.

As you see, both downforce and drag are pretty low and balance is not as forward as you would want it in a slower track. But when you work with very low donwforce configurations, in my experience it is normal to target for a more rear biased aero distribution, to increase stability and give the driver some more confidence. That´s of course not so strictly necessary when you have already much more downforce, like for example in a Silverstone configuration.

[MadMatt]

Fantastic, thank you very much, and thanks to him for sharing the info. These are good numbers indeed.

I have measured a frontal area of 1.634m^2 with the files I've got, so it gives us the following absolute aero coefficients:

- Cl = 2.081
- Cd = 0.459
- L/D = 4.53 : 1

I will simulate in unsteady state since the rims are well detailed, so it is worth it.

[silente]

to be honest, i am not even sure he simulated with rotating wheels, but i think so.

I can tell you, from the info i have (which are sometimes much more detailed, see my Blog for my latest project) regarding other LMP cars, the drag has dropped dramatically and efficiency is pretty high to be a LM configuration.

On the other hand, Downforce is of course on the lower end as well...I expect Manufacturers to have somehow more DF.

If i remember correctly, the numbers published by Toyota was showing a ClA of about 3.8 but i should double check.

For which Uni and which topics are you going to work (if you can say it here, otherwise i can send you a PM)?

[MadMatt]

Yes, efficiency increases as you reduce downforce, that is a natural property of airfoil profiles. I did tests on different profiles some years ago:



X axis is angle of attack, Y is the L/D ratio, so for sure if you want low drag, you have to lower the AoA of the wings, and therefore you increase your efficiency. I don't know about Toyota, but here is a picture from a presentation they did on the TS040:



Source here: http://car.watch.impress.co.jp/docs/new ... 80406.html

They obtained these values at 280kph, which if we take a frontal area of 1.634m^2 (same as Perrinn) and air density of 1.18415Kg/m^3, gives us a Cl.A of 3.971, so a bit more than the Perrinn and close to what you remember. Drag unknown tho.

I will send you a PM

[silente]

any news about your CFD simulation? any result?

[MadMatt]

Not yet, no, got a new job and had to move house so very busy with other things, but I will get back to it when I have a bit more time (my priority during free time, apart from the mentioned job and house is the KVRC but we will see).

[Ciro Pabón]

Thanks, Matt, we'll wait. This is, frankly, a rare opportunity to learn a bit for most of us.

[GTRdesign]

Has anyone here managed to obtain these CAD models? I see they are no longer available on the Perrin site...

[RicME85]

Has anyone here managed to obtain these CAD models? I see they are no longer available on the Perrin site...

http://hobbyfoam.blogspot.co.uk/2014/09 ... cases.html

[krisfx]

Has anyone here managed to obtain these CAD models? I see they are no longer available on the Perrin site...

They're on Onshape as freely available CAD

[GTRdesign]

Thanks RicME85 for the links to the stl files!

krisfx, I've checked on Onshape but there only seems to be models of the Perrinn F1 car?

Does anyone here perhaps have it as step, or iges... ?