Building my own sportscar (3D model)

[MadMatt]

Hello guys !

I had this idea in my head for years now. Always wanted to design my own sportscar more than just on paper. And like a lot here, I spent tons of hours doing this. Now I have some knowledge of 3D modeling, so I finally started !

This project will keep me occupied for few months (my aim is to end it at Christmas) and I will only work on it during my free time (when I'm not doing sport or video games, or more important, work for school which takes lot of time). To design the car, I will use CATIA V5 from DASSAULT SYSTEMES which allows (as you may know) to draw unlimited parts with an extreme level of complexity (they didn't use it to draw F1 cars without reasons).

But why would I build a sportscar ? There are so many on the market at the moment, and very good ones, with innovative technologies and so on ! Well, for the the sportscars are the pinnacle of closed cars. I have always loved the group C cars, so therefore I decided to make some sort of mix between F1 technology/architecture, modern/old sportscar design but still good enough to drive it on the road to get your bread at the local dealer. Of course the car would not be homologated for racing, but for track use it would be perfect ! A good example (the best one to me) of such car can be seen in the Dauer 962 which was a mix of this some 15 years ago, and I decided to take this as an inspiration to make my own sportscar(although the Dauer was based on a race car while my car will be built from scratch).

I don't intend to have this car built in real because it would require a lot more than few months' hours of 1 man to do so, so I'm only building it as a detailed 3D model, as detailed as possible, and as real as possible. Hopefully to make simulation on it, and try to develop it (trying to use this experience to better understand the aerodynamics of the car).

It is a very complexe project which, you may think, require lot of knowledge about the whole car and all components of it. Good ! I'm a mechanic on cars (did an apprentice some years ago), doing now a bachelor as a mechanical engineer, and plan to start a master of sciences in motorsport department in the UK. And I've always admired racing/rally cars, so I learned a lot by myself over the years by reading books/articles, wathing millions of pictures/videos. I will use all this to have this car built with a good output result !

You will be able to follow here the developement of this car because I will post pictures of the 3D models I'm gonna build with the evolutions. Feel free to comment/participate, I'm of course open to suggestions, remarks and every constructive thing !

But enough talking, here are the specs ! They are not fully fixed yet because I'm only at the first steps of the project, but these are the specifications I think that would be good for the sportscar I plan to build.

- V6 engine @ 72°, 3000cc, with 2 turbochargers and 1 supercharger
- 2 seats with lights, handbrake and GPS
- 6 speeds sequential gearbox with paddleshift
- carbon bodywork
- active aerodynamic devices (will be explained more in detail later)
- 800bhp
- 1100kg

The aim of this car is to be the 21st century Dauer 962, I hope you'll enjoy it ! I will update the thread at least at the end of every month, so expect an update in 20 days !

Enjoy and thanks for reading !

[G37Sam]

Start off by drawing your chassis on CAD and fitting all the parts in (including driver models and seats). Once that is done, try running some tests to make sure it can handle all the loads/stresses.

Leave forced induction for later, once the engine runs 100% in N/A form, then you can start working with forced induction. Do you plan on doing the engine tuning yourself?

[MadMatt]

Start off by drawing your chassis on CAD and fitting all the parts in (including driver models and seats). Once that is done, try running some tests to make sure it can handle all the loads/stresses.

Leave forced induction for later, once the engine runs 100% in N/A form, then you can start working with forced induction. Do you plan on doing the engine tuning yourself?

Yes, I started modeling the monocoque, the driver and the racing seat, so I can get an idea on how big the car is. I have never done stress tests with CATIA V5, but I will ask the teacher on what is possible for me to do at my current level !

About the engine, I just did a very simple modeling of the bloc/head now with exhaust manifold and turbo. I think it is important to model this early, so I can choose where to locate it and design the chassis under the car for ground effect.

What do you mean by "tuning yourself" ? I will just take an existing engine which fits my requirements, try to get the dimensions, model it and fit it to the car.

[marcush.]

CAD is not a drawing exercise...so you need alot of technical information about cooling demands of the engine and basic numbers for the radiator performance fluid flows etc .
With that blackbox approach your design will not be very integrated so my way of doing it would be from a much broader view of what you want to achieve and how you would attempt to realise the goals you have set yourself.

Maybe you try to borrow doug nyes book Driving ambition about the making of the Mclaren F1 ...a fantastic read about how Gordon Murray went about creating his boys dream of a car...
unfortunatelly it is a very expensive book and the guy i loaned it preffered not to give it back to me..

[MadMatt]

CAD is not a drawing exercise...so you need alot of technical information about cooling demands of the engine and basic numbers for the radiator performance fluid flows etc .
With that blackbox approach your design will not be very integrated so my way of doing it would be from a much broader view of what you want to achieve and how you would attempt to realise the goals you have set yourself.

Maybe you try to borrow doug nyes book Driving ambition about the making of the Mclaren F1 ...a fantastic read about how Gordon Murray went about creating his boys dream of a car...
unfortunatelly it is a very expensive book and the guy i loaned it preffered not to give it back to me..

Yes I know I would need to get the data of the components. To draw them I always try to get the exact dimensions from the manufacturer, so the size is pretty much spot on. About the cooling, well I would say that I take dimensions of existing cars for the vents, which are a good way to start with, so I have a safe basis. A V6 engine doesn't require a lot of cooling, and as I take dimensions from V8 cars as basis, I think it is oversize. But that's the basis, then it will be possible to optimize everything.

At the moment, I just try to select the parts I would like to have in the car, get the technical informations, then draw them and include them in the overall 3D model of the car. This gives me a general idea of the components can be included. Of course I will not put the V6 at the very front of the car with a rear wheel driven car, but what I'm trying to say is that I take for example 5 differents cars, and mix the ideas to include in my car. So I think everything will be "doable". It probably won't be 100% efficient of course, but the development margin will be big !


P.S.: I want to apologize for my English if I make mistakes, but its not my native language

[machin]

How about downloading a set of current rules from any one of the current crop of sportscar championships and designing your car around those? You can then play at trying to "bend" the rules here and there..?

[MadMatt]

How about downloading a set of current rules from any one of the current crop of sportscar championships and designing your car around those? You can then play at trying to "bend" the rules here and there..?

Because I really want to make my own car, a sort of car with innovations that have never been used before (on the road for some of them) !

[autogyro]

I wish you the best of luck reaching your goals Matt.

However, to find something completely new in engineering design is almost impossible today.
In the early days, new ideas were found often but now, most designs are either variations on a proven theme or the taking up of past ideas that were not possible when first thought up, mainly because materials were not avaiable.

I do not want to put you off in any way and perhaps you will find something new but IMO it is just as important to study the past for ideas that can be adapted for modern use.

[MadMatt]

I wish you the best of luck reaching your goals Matt.

However, to find something completely new in engineering design is almost impossible today.
In the early days, new ideas were found often but now, most designs are either variations on a proven theme or the taking up of past ideas that were not possible when first thought up, mainly because materials were not avaiable.

I do not want to put you off in any way and perhaps you will find something new but IMO it is just as important to study the past for ideas that can be adapted for modern use.

Thank you !

Yes finding something new is almost impossible, but who knows ! F1 discovered F-duct which was a really big innovation, so you never know ! And my car does not have to follow any rule except not being too extreme so it can still be driven on the road !

And I am using this project so try to improve my skill using CATIA V5 and maybe it could be a good project I can show to some future employees on what I can do.

[Tim.Wright]

Hi Matt,

I'm doing a similar thing also in Catia. Just for fun at the moment and I'm not looking at pushing things innovation wise as much as you.

Though in anycase, Ive set up a fair bit of the CAD model, so if you need any advice or ides on that give me a yell. My product structure has basically every part driven by skeleton parts with no part-to-part linking. This keeps things nice and stable.

For now all I can say is start out with an excel document with your product structure and follow that in your CATProduct.

At the moment my main assy looks like this.



You can see there is some kind of structure in my product tree on the left. If you make this up as you go I can guarantee you will get into a mess very early.

Tim

[MadMatt]

Hi Matt,

I'm doing a similar thing also in Catia. Just for fun at the moment and I'm not looking at pushing things innovation wise as much as you.

Though in anycase, Ive set up a fair bit of the CAD model, so if you need any advice or ides on that give me a yell. My product structure has basically every part driven by skeleton parts with no part-to-part linking. This keeps things nice and stable.

For now all I can say is start out with an excel document with your product structure and follow that in your CATProduct.

At the moment my main assy looks like this.

http://a.imageshack.us/img820/5071/radiatorsfitted.jpg

You can see there is some kind of structure in my product tree on the left. If you make this up as you go I can guarantee you will get into a mess very early.

Tim

Thank you Tim for your helping offer !

Nice car that you've got already I hope you'll finish it sometime !

For my structure I am doing it like this.

First I make the parts, for example :

- driver
- seat
- engine
- exhaust
- gearbox
- turbo
- monocoque
- chassis

Then I make products where I put some of the parts made earlier, for example :

- S01.transmission (regroups all parts related to transmission such as : gearbox, driveshafts, ...)
- S01.cockpit (regroups all parts related to the cockpit such as : seat, driver, monocoque, dash, ...)

And finally I have a last product which is the car itself :

- S00.car (regroups all S01 products)

This is how I learnt. I will also have to separate the moving parts from the rest !

[MadMatt]

My thread does not bring that much interest but I guess I have to update it with some pictures ! So after 75 hours of work, I can upload some pictures there. Only a few for now.

My target has been to try to design all major components so I could include them and see if the proportions are ok. Keep in mind that I'm doing everything from scratch, that I haven't done anything on paper, so it takes time to get a final result directly as a 3D model, because you sometimes have to change nearly the whole part due to new constraints or components !

So here is the monocoque. Of course not finished at all, but you get the idea of the proportions ! The cockpit won't be large, with big side pods for air to reach the engine at the back. The car is 2.00m wide so still plenty of space inside ! the height of the monocoque is 1.00m so really low on the ground ! You can also see large tunnels on the sides, just behind the front wheels. This is for ground effect !



Now the provisional assembly of the cockpit from the back. You can see that I will use a MOTEC display with a TFT screen on the side. Again this is a provisional design, but I had to post something here as I promised ! You can also see that between the 2 pillars at the back of the monocoque is the fuel cell behind the small cover. Notice also the large side pods.



And now the chassis. Again still work in progress but you get the idea of how extreme I want the ground effect to be on this car.



And finally just a picture of one of the front wheel I decided to draw correctly ! You can see the car will run BBS fans over the centre lock wheels, just as a racing car !





So on an aerodynamic point of view, not only the car will have a variable ground effect (by modifying the angle/shape of the venturi tunnels), variable front/rear wings, but it will also have variable weight distribution by moving ballasts inside the monocoque structure. This is not it, and I have lot of other ideas to try to model, but it takes time !

From now on I won't have so much time in my hands so it will go slower, but I will still post updates ! I've done a lot more than what I've shown, but again everything has just been drawn to put on proportions, see what's possible and what's not. There is a now "old" image/version of the whole car, you can the idea of how it may look in the future !



Feel free to comment, add your thoughts !

[Just_a_fan]

The floor tray looks a little odd. It appears that you have tried to incorporate a double diffuser style forward feed to the diffuser. Why? You would be better to keep the floor as flat as a possible.

Also, that is a huge diffuser - what balances it at the front? A front diffuser linked to a nose splitter is probably required and even that wouldn't balance that diffuser.

[MadMatt]

The floor tray looks a little odd. It appears that you have tried to incorporate a double diffuser style forward feed to the diffuser. Why? You would be better to keep the floor as flat as a possible.

Also, that is a huge diffuser - what balances it at the front? A front diffuser linked to a nose splitter is probably required and even that wouldn't balance that diffuser.

The floor is still at early steps but yes that's quite a big diffuser. I don't plan to use a rear wing, or at least not a big one, and I will use a sort of front wing as used on some of the 956 Porsches (Brands-Hatch versions). Or maybe a front diffuser, I do not know yet, but as there is already the radiator at the front, I do not know yet.

But what do you mean by double diffuser ? Yes there are 2 venturis (1 on each side of the car) and one just behind the gearbox. The main channel for the venturi is taken from the side of the car, and there is a second channel which takes air from just behind the front wheels.

Do you think the rear downforce may be too much to compensate it at the front ?

[MadMatt]

Not a lot of feedback there, I thought this forum was about technical stuff. Ok this is not a F1 car, but still, I think people there should be more interested in this project rather than just a design project over the body of a F1 car for example.

Anyway I will continue to update this thread, for those who are watching but staying quiet.

So I started making the front and rear body, and continued to work on the shape of the monocoque and the chassis. These elements are of course 100% combined with each other, so once you make a modification over one, you have to modify the others too, but by doing all at the same time, you immediately see the modifications "in real" ! Easier to imagine and continue to research different possibilities.

So first here is a slightly updated view of the car's stuff. I have not started think about a way of getting downforce at the front yet, but I'm still thinking about ground effect too. I might reduce also the size of the rear venturis because I'm afraid they could generate too much downforce at the back, making the car understeer a lot !



And now a bit or progress on the body so far. The rear is not adjusted at all and the front has still lot of work to do, but that's just to get an idea !



Comments appreciated, as well as suggestions/opinions !