New season, new car, new challenges. After getting a promising end last year, i wondered and tried to learning some cad softwares. I learned the fundementals about solidwork but im not comfortable enough to design at the moment. But that experience give me some great insights about how to design and how not to.
Firstly i looked a way to create my own airfoils. After some search i find out that there is a software called QBlade. So i designed 6 airfoils and tested on the old software as a single element rear wing for the 2017 championship. Results and the shapes are below.
For this year, i wanted something new and fresh (kinda thinking like McLaren there [i hope it won’t result like McLaren]) and went to a complete diferent concept with a high nose and fully closed sidepods. While last year i had something similar again on Monaco, it didnt get the results and i got some penalties for breaking rules. After that i ditched the high nose for the rest of the season.
First concept was finished off season for trying new things for cooling. After getting some positive numbers, i decieded to stick with the high nose and develop furter. Got around 40 different versions of the current car and i only finished the last simulation a couple of hours ago. The focus was mostly on the front end since the new software has a lower drag and also lower downforce numbers. Tried a lot of things on the front end, big wing like the Variante cars, different dive planes, different shapes on the diffuser.. At the end of the day, i ditched every solution that i tested and tried the number 3 airfoil that i created on the qblade on front end with a single diveplane and a upper wing. Here is some pictures of a couple different versions and a picture for the transition of the nose to floor for CAEDevice 🙂
As the followers known, last year on the last 3 races, i used a brand new car for the efficiency races and got some good results. One of the key things about that car was the front pod diffuser. I almost doubled the front end downforce with that so i thought to using something similar this year too. But instead using a pod difusser that guides the air into the wheel area, i created a duct in front of the front wheel that i’m calling “P-Duct”. Basicly it works kinda like the s-duct, getting air below and send it top of the fender to the rear fender and rear wing while lowers the amount of air that goes around the wheel thus lowers the positive lift because of the wheel wake. Tried to get some venturi effect for more suction by make the middle of the duct narrower but sadly i couldnt test the difference with and without that. I went with the venturi one for this race.
Here is some screenshots:
Next race is the legendary LeMans, where a lot of drama happend on the past. Last race, my car suffered once again from cooling. There is no doubt that if my car had a %100 engine cooling, with the penalty that CAEdevice suffered, i had podium finish on Brazil.
After the race i contacted André about my cooling issues, mainly about why i had a different numbers on my tests. (i had around 6[m^3/s] on tests -twice more than required but -1.76904[m^3/s] on the race) Turns out there is a bug on the openfoam that measures the mirrored measurment surface. On wflow, Openfoam uses a symmetry condition that measures only the one half of the car, so the other half isn’t there on the initial simulation.
With this info, i again changed the cooling but not drastic like the last change. First of all, i didnt mirror the midsurface part and give it more polys for a better measurment. Changed the porous media surfaces for better mesh quality ( on past i was creating the face first and extruded to a box, on my new approach i created the mesh directly as a box and shaped it) and opened up the air intake. I had a good airflow but the results wasnt good enough. So i changed the location of the cooling surfaces and moved it back to the car. This did the trick and give me around 3.4[m^3/s] airflow. But as a side effect, car lost some aero efficiency.
Besides cooling, i had some minor changes on front of the car for optimizing purposes, minor changes to diffuser area, 3 vortex generators back of the cockpit and changed the rear wing to TF approach. I tested the vortex generators back on the Brazil car, and found out that it helps to generate small amount of downforce back on the car so i installed them for this race.
Unfortunately i had a busy week and didnt test the car much, and it occured to me that i could have something illegal on the car on thursday. After checking that part of the car, i had to change it because it was indeed illegal. I made a last minute change to the rear part of the car and because of that cop shifted to front around 0.05. Im not happy from that but i ran out of time so there is nothing i can do about that.
Since its the last race, i have no problems to share some more images about how my cars underbody works, what does the vortex generators do and some general images.
After the devastating result on Sepang im motivated to do a better job for the next race on Brazil. Before the results come in for Sepang, somehow i knew that i didnt do a good job on cooling and optimizing the COP and the details but didnt realized it is that bad. So i changed the car drasticly for the next race for having to acomplish the objectives that i had in my mind.
-Better cooling (obviously)
Achieving these objectives is number one priority for all competitors of course so no real suprise there. But making it reality is the hard part of this competition. Since the first race of this years competition, i suffered heavy from cooling. On the preseason tests for KVRC, my car had a very good downforce figure but had a bad cooling. Same for the first race. When the competiton shifted to MVRC, i got 2 penalties but my car still had a strong figure on the downforce department but not on cooling. So i needed a fresh approach to cooling and i run out of ideas.
My close friends know my passion about Motorsports and also they know that i am a diehard BMW fan. So naturally i checked the BMW V12 LMR and look for some inspirations.
Then i realized that i can easily copy the cooling system that V12 LMR has. So after an hour of work, i changed the geometry on front of the car to generate better airflow to the hx surfaces.
First results were very promising. I had a positive (actually very positive results; +6 m^3/s) result on cooling and instead of getting some positive drag, the result show that i managed to get some negative drag with this new setup. (also worth noting the new single flap rear wing)
The car gained a lot of downforce from the optimized front diffuser and the diffuser tunnel that leads to the end of the car. I’m still trying to optimize that for using it to gain downforce on rear diffuser for lowering the wing angle even more to gain some more speed on straights.
With the changes car has gained around %21 more downforce and lost around %5 drag.
Over the course of development the car changed a lot so i dont have any problems to publish some images from Paraview
1st and 2nd picture clearly shows how the diffuser gets the most airflow from the side of the car.
I will probably publish some images of the final car after submission over.
Since the next races are all about efficiency, i developed a new car for the 2nd part of the season. I tried a design highly inspired from the 80’s group c cars for the next races. Last year i tried that style and had some success but that car lacked a lot of frontal downforce back then. So i did some research on web and as i suspected i didnt fully utilized the front diffuser. As everyone know back then the challenge was getting most downforce from the ground effect. Since the rules on Mantium Challenge doesnt give us to utilize the fully ground effect tunnels, we cant produce the same downforce levels but i still managed to get around 5000 nm downforce with a fairly simple design
Apart from the body, i lovered the rear wing flaps and reduced the angle of attack rate on the 2nd flap. The heat exchangers are still middle on the car. As you can see, the air goes in to the ducts from the top of the body and leaves trough the wheel arch. The reason of the wheel arch region was to not disturb the air flow too much. I still lack some frontal downforce but its not extreme. And since it doesnt have that big of an effect on the laptime i didnt poke much that area.
I didnt test this concept on MVRC Cfd atm but One-Click CFD gived some promising results. I anticipate to get lower drag and lift on the MVRC Cfd since my last race results was like that.
So some numbers from one-click cfd then:
Cd.A: 0.95 m2 Cl.A: -4.21 m2
CoP : 1.860 Total drag: 1143.59 N
For starters, i’m not an expert and mostly i’m doing my stuff by instinct and getting inspired from other desings. If you guys wanna see some professional stuff and trying to learn something, this is not the right place.
On this blog, i will try to document my progress on my car for the Mantium Racecar Challenge. Besides that, i usualy have some ideas from other stuff so there will not only be the MVRC stuff but some other stuff aswell.