Parametric Racecar Aerokit design [MVRC]

[machin]

I wanted to share with you all the really fantastic CAESES parametric aerokit design app that can be used to create a car to compete in the MVRC championship, which if you didn't know is a championship for user-designed cars resembling LMP1 style cars, but with a more potent underfloor design.

The app can be accessed from the championship website (www.mantiumchallenge.com/caeses/). It works entirely within your browser, so there is no need to download any fancy software....

Once loaded up you are presented with three pages which allow you to design three different parts of the car: the front wing, the rear wing, and the underfloor/diffuser. The main body of the car being provided by one of the championship sponsors (CAEDevice).

You adjust the design by modifying the sliders on the left of the screen...


This approach is far better than merely drawing these parts free-hand as it means you can easily make precise adjustments and also easily return to a previous specification by returning to the original settings.

The final round of the 2017 MVRC championship is rapidly approaching and I thought I would enter a car. With no data to start with I would be at a significant disadvantage compared to the existing entrants... so my only choice was to look at what the other competitors are doing...

I went to the Mantium Challenge webpage and looked at the published images and data from the last round for the Brook Motorsport car:-






Using the CAESES app I recreated as best I could a set-up that looked as close to the Brook Motorsport car as I could...

I then loaded up the VIRTUAL STOPWATCH lap timing software used by the MVRC Championship (Shameless plug; www.competition-car-engineering.com/MVRC_Timing.htm !!!), and put in the aero coefficients for the Brook Motorsport car and selected the Le Mans track. The data window at the bottom of the VIRTUAL STOPWATCH page showed me what I would need to do to make the car quicker around the Le Mans track...



...So I headed back to the CAESES app and set about making the adjustments which I thought would help me achieve what I needed: namely a more rearward downforce balance and a lower drag configuration.... Once created I just downloaded the parts and ZIPed them up ready for submission to the championship when the entry date arrives in a week or so's time so that the CFD analysis can be done by the championship organisers and then all cars will be run on VIRTUAL STOPWATCH to determine a winner...

When I receive the CFD results I will post a further update. I hope this little post might encourage others to try the CAESES app and join us on the [virtual] track next year!

[CAEdevice]

Very good report! MVRC staff should make a guide from it.

[roon]

Cool post. This is almost like having what you might call customer or garage teams competing with factory teams. Those with fewer man-hours & experience vs. those with more man-hours & experience. Or the difference between LMP1 & LMP2 in terms of in-season development capability.

[LVDH]

Cool report, thanks machin.
I really think the App is great. Anyone wondering if he can create a car for MVRC should have a good look. Even if you can design a whole car with your CAD tool, it is also very useful to build a good wing.

[flynfrog]

I couldn't get it to load.

[machin]

I've had a few instances where it didn't work first time, but after a couple of refreshes it works for me...

...once it is working you also need to be careful not to leave the app inactive for too long or it kicks you out...

[LVDH]

This whole thing is obviously still very new and Friendship Systems are learning about issues that they are fixing. I use Firefox with an extension that did not work together with the App. Changing the browser helped me. And that is what I recommend. If it does not work for you, first try a different browser.

[CAEdevice]

It works perfectly with Chrome.

I would like to develop a new customer car for the next year. I would like to provide CAESES a more complete study, giving them more instuctions about the shape that the wings and diffuser can have. It would be important to have the rulebook and tracks ready aso soon as possible.

There will be important news: I will realease a parametric version of the custom car for Solidworks and maybe for Creo and FreeCAD.

I would have two suggestions:

1) the performances of the custom car should be nearer to the top class (same engine: I will dimension the cooling ducts in order to easily reach 3.0 m3/s)

2) why don't we have a constructor challenge too?

[LVDH]

Hi Matteo,
these are all good ideas and we can work on these the next weeks together if you like.

Right now, more important news: I have sent out the last email with the submission link. If anyone is not on the list, please complain. I went through all teams and noticed one that was not on the list. I hope this person is not sad that I overlooked him so long. I always announce here on the forum that you should all make sure to receive the submission details (I am only human and mistakes happen). I wish everyone a good last race. Some cars have already arrived and are looking good and eager to win.

[LVDH]

Wrong thread, sorry.

[machin]

I promised an update after the race... First of all I will post some CFD images to whet your appetites!

After each MVRC race each competitor gets a ZIP file with the results of the CFD analysis, and also over 400 images of CFD post-processing, so there is no need to learn new CFD analysis software (you need to concentrate on simply understanding what each image shows!)

Below I have given a very small sample of what you get:



Pretty cool, right?

Analysis of the results to come in a later post!

[CAEdevice]

I am very interested about your comments, this car is very similar to the one I used in the first two races and has many details in commun with that I used in the efficency races.

The main difference is the low nose: I preferred to release the intro car with a low nose because it produced more front df, thinking that it would have been easier to balance the car with the rear wing if necessary.

The high nose version (see my LeMans car) gives more floor df, but it may cause balancing issues.

Btw: in a real race the high nose version would be much more stable during braking because it is less sensitive to the pitch angle variations.

[machin]

I am very interested about your comments,

As the winner of 4 out of 5 races this season I don't think there is anything you'll learn from me... but it'll be fun anyway!

[CAEdevice]

I am very interested about your comments,

As the winner of 4 out of 5 races this season I don't think there is anything you'll learn from me... but it'll be fun anyway!

On the contrary, I finished the challenge without understanding how the flow works in some specific areas. To read your point of view will be very interesting.

Among the others, the weak points of my car are:

- side channels of the diffuser (they need to receive more air)
- air behaviour underfloor behind the front wheels
- expansion "strategy" inside the cooling airducts
- flow blockage between the sidepods and the rear wheels cover

I think I will need another year to completely understand the car!

[machin]

Among the others, the weak points of my car are:

- side channels of the diffuser (they need to receive more air)

Do you think we are simply asking too much from the diffuser: the outlet area for the under-floor flow (measured as a vertical plane perpendicular to the car centre-line at the trailing edge of the rear bodywork) is something like 0.5m^2... whereas the "inlet" (measured at the leading edge of the front wing/splitter) is only something less than 0.2m^2, and some of the air that does go under the front wing finds it's way above the floor around the sidepods... so not enough air is getting to the diffuser, hence (possibly) poor flow in the diffuser side channels... ???