Khamsin Virtual Racecar Challenge 2015

[machin]

It seems that I do not have to fix anything this time.
Does everyone get the emails at the same time?

This time I can at least claim to be first to release some images of the new car:

http://mantiumcae.com/wp-content/upload ... 24x576.png

http://mantiumcae.com/wp-content/upload ... 24x576.png

As you can see, I made a few adjustments compared to last time.

Looks nice....

[LVDH]

Some doubts about the rear wing...why that choice?

Well, there was a somewhat long process behind this.
So after the rear wing profiles of the top cars were posted I analyzed them.
Turned out that the JJR Wing was the best as the following (normalized) chart shows:


So I took that wing and started optimizing it. I tried a lot with different parametrization approaches and used various optimization algorithms. I could not get anything better. I got some with greater efficiency but with less downforce. So I put the JJR wing on my car and ran with it.
When I created the renders this wing showed less talent in carrying my company name.
For the render I took a single element wing. The rest should be the submitted car, though.

So the question that remains is where does that profile come from? It fits so perfectly with the regulations it is almost amazing.

[CAEdevice]

Some doubts about the rear wing...why that choice?

Well, there was a somewhat long process behind this.
So after the rear wing profiles of the top cars were posted I analyzed them.
Turned out that the JJR Wing was the best as the following (normalized) chart shows:
http://mantiumcae.com/wp-content/uploads/rrWings.png

So I took that wing and started optimizing it. I tried a lot with different parametrization approaches and used various optimization algorithms. I could not get anything better. I got some with greater efficiency but with less downforce. So I put the JJR wing on my car and ran with it.
When I created the renders this wing showed less talent in carrying my company name.
For the render I took a single element wing. The rest should be the submitted car, though.

So the question that remains is where does that profile come from? It fits so perfectly with the regulations it is almost amazing.

I can't understand the meaning of the charts

Anyway: I've tested three different design concepts for the rear wing, with similar results. I'm convinced that after the first 2 o 3 races everyone will reach the maximum possibile efficinecy for the rear wing and diffuser (expecially if Chris will publish such detailes sections... I'd prefer to not see such details for the second race )

[variante]

Some doubts about the rear wing...why that choice?

Well, there was a somewhat long process behind this.
So after the rear wing profiles of the top cars were posted I analyzed them.
Turned out that the JJR Wing was the best as the following (normalized) chart shows:


So I took that wing and started optimizing it. I tried a lot with different parametrization approaches and used various optimization algorithms. I could not get anything better. I got some with greater efficiency but with less downforce. So I put the JJR wing on my car and ran with it.
When I created the renders this wing showed less talent in carrying my company name.
For the render I took a single element wing. The rest should be the submitted car, though.

So the question that remains is where does that profile come from? It fits so perfectly with the regulations it is almost amazing.

So, basically that's not your race wing...just a marketing substitute

Interesting data those you've worked out, although they could be influenced, more or less heavily, by relative airflows varying from car to car, obviously. Interesting to see how well JJR's wing works despite its unsusual design.

[julien.decharentenay]

Hi Gents. A gentle reminder that the re-submission portal is closing tonight... Make sure you get in on time.

And great renderings!!!

Airfoil profiles: for those that are not aware, there is a software called XFoil http://en.wikipedia.org/wiki/XFOIL which can be used as a stand-alone to assess airfoil performance. There are limitations, but is likely to prove useful.

[LVDH]

Interesting data those you've worked out, although they could be influenced, more or less heavily, by relative airflows varying from car to car, obviously. Interesting to see how well JJR's wing works despite its unsusual design.

Well, I am showing the force coefficients. AoA is out of the equation, though.
But the force is proportional to Ci and v².
If you have a look at those three rear wing profile pictures posted earlier you can take the color-info to figure out who did the best job feeding that wing with some nice high velocity air.

The huge front wing approach that seems to have crystallized itself out really messes up the flow in the rear. But my tests diverging it sideways all failed.

[variante]

If you have a look at those three rear wing profile pictures posted earlier you can take the color-info to figure out who did the best job feeding that wing with some nice high velocity air.

As i said days ago, i don't think those images show the actual performance of those wings, due to some kind CFD error. Your own test confirms that, as the seemingly bad performing CAE's wing is actually as good as mine and not far away from JJR's.

The huge front wing approach that seems to have crystallized itself out really messes up the flow in the rear.

Yes, a little bit... However the usefulness of that device becomes evident when the demand of front end downforce increases and the airflow directed to the diffuser cannot be further sacrificed; thus what is sacrificed is the rear wing, an often ovverated element.

[cdsavage]

First images of the round 2 entries (alphabetical order):

[cdsavage]

If you have a look at those three rear wing profile pictures posted earlier you can take the color-info to figure out who did the best job feeding that wing with some nice high velocity air.

As i said days ago, i don't think those images show the actual performance of those wings, due to some kind CFD error. Your own test confirms that, as the seemingly bad performing CAE's wing is actually as good as mine and not far away from JJR's.

I can confirm that the round 1 CFD images released are representative, the Variante rear wing produced about 2.5x the downforce of the CAEdevice rear wing. In the case of CAEdevice, due to another wing element upstream of the rear wing, the apparent AoA of the rear wing was very low. You can get an idea of this by looking at the streamline direction upstream of the wing in the CAEdevice image.

[AratzH]

Very nice pictures!! Looks like Variante's car has had some "offsprings" haha. Such massive front wings... and very interesting concepts.

I can't wait to see the results!

[LVDH]

I like the TF car very much. I hope it gets a good position.
These front wing designs are missing elegance and style.

[CAEdevice]

Well, Variante's style front wing rules! I have to admit that I'm studying a similar solution for race 4.

About my rear wing: Chris is right about the low df, but I'not convinced that the cause is the wing shape rear suspension cover. The problem (not completely solved) is also related to the wheel arches and to the general shape of the engine cover (but I have advantages too ).

[variante]

Looks like the competition is going to be much tighter this round as design philosophies are converging.

As for my car, all i can say is that i'm not going to win this one: having had no time to properly test the "upgrades" i had to make a bet, which i lost. The new car is actually worse than the previous one, exept for some details.
I'll release a report about it in the following days, hoping that this experience of mine helps some of you (or, at least, make you laugh...)

[CAEdevice]

You had such a great advantage in the 1st race, even if you lost 5% of the total df you could win

If the results of "local" solver are comparable to the "official" one, I would be quite happy with the total df, but not at at all with the balance. I can't direct the airflow under the floor and I loose to much air that doesn't reach the diffuser.

[RicME85]

Its interesting to see peoples interpretation of Variantes front wing.
I studied the airfoil profile and positioning in his car and replicated it as best as I could with my modelling skills.

I do like the TF car, can see that being the way things go once we go low downforce.
The Mercury car is very unique in its looks.
Matteo - I like what you have done with the upper crash structure, looks a neat solution.