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In terms of preventing flow separation, the area behind the wheel arches look better. But what is the reasoning for the high nose design besides aesthetics? I think your "original version" would give you the better aerodynamics as well. Usually a high nose imparts an aerodynamic function in increasing the efficiency of a front wing or diffuser, but at least from the pictures provided it doesn't seem like you're using a full width front diffuser or wing anyways?

Take some time and study some pictures of the Caparo T1, Audi R-15, Audi R-10, and Bentley Speed 8 (2003 version) which all have some elements of similarity to your current design.

Keep up the good work.

Ken

Hi Ken,

With the nose, apart from the aesthetics, I wanted to use the nose tip area for downforce. My original thinking was to have the nose shaped like a wing with a void (hole) in the upper surface which would allow me to shape the underside of the nose and allow the flow to escape through this hole (although I had though about this a couple of years ago, I saw it done on the 09 or 10 Ferrari F1). I then though I could possibly use this space under the nose to generate some more downforce, of which I hadn't done much thinking.

There are some guys over on the F1technical.net forums who have been doing free sims on some designs the guys on there have been coming up with (truly amazing some of them) so my plan was to try and do some CFD runs myself if possible.

Speaking of which, I know the Open Foam code is available for download, but does anyone know how to use it? Anyone have an interface? How about getting a group of people together to create a free open source CFD package. I for one would definitely dedicate my design skills (I'm a graphic/web designer).

Anyway, back to the nose... I'd love to make a high nose work. I know it's just about playing around with it some more designs. There are lots of ideas in my head, but so much harder to get onto screen...

Pete

This is what I meant with the nose. Quite crude but you get the idea. Whether this would work I dont know....

Pete,

I used to manage a research program for naval vessels, with scientists working in ship structuures, hydrodynamics and noise. Our work included both in-house and contracted code development, and use of third-party codes, including use of Navier-Stoke equations. In some cases, in-house development accelerated our appreciation of the problems at hand, but use of third-party codes could be more expedient for actual problem solving, where we could justify the license fees.

When I think back to my colleagues working on these problems, and then examine the apparent skill set and time availability in the Locost 7 community, I don't see development of an free open source CFD code as a practical proposition. The level of effort invoved in such development is typically measured in person-years: the average PhD candidate doing CFD development in support of a thesis only addresses a narrow slice of the CFD problem space, and typically relies on third party software for the core CFD solver. Your own user interface/visualization skills would be valued in a open source development, but the real problem lies in the 'computational' part of CFD, not the 'colourful' part (the cynics name for CFD is 'colourful fluid dynamics', since a great user interface will sell many a weak CFD package).

I am sure that there are forum members out there who could develop CFD solvers, but I also believe that they would rather work on building their cars than developing a CFD code that would in all probability never approach the capability of those already available, or even reach the state of development necessary for the prediction of flow conditions around an automobile. I recall that the streamline posting made elsewhere in this forum (see copy below) was based on a commercial code. The visualization is impressive, but what is more impressive is the hidden CFD calculations necessary to predict the flow conditions in way of and behind the flat plate windshield.

I wish it weren't so, but the physics of CFD are way harder and more labour intensive than either end of the user interface.

_________________
Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

Yo, Bovax-
Put an oil cooler in that nose, and let the airflow cool the oil as well as make downforce. Added benefit is the driver will know immediately if there's an oil line leakin...

An airfoil surface across the front, from fender to fender, was a common design in prototypes for a while there. Similar to what you're doing, just wider. They seem to have gotten away from that lately, but I don't know if rules caused it or wind tunnel results drove the design change.

Good looking and interesting designs you've shared, keep 'em coming!
Regards-
JD Kemp

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

Hi Warren,

Thanks for the really interesting insight I admit it is a huge task, but then again there are guys out there who love that sort of thing, no harm in asking.

Not sure if you've seen this? http://www.openfoam.com/ - OpenFOAM is a free, open source CFD software package produced by a commercial company.

I need to look into it more but I still think that the right group of people could make something of it.

I'm off on holidays for the next 10 days so I wont be making any further updates, but feel free to lend your suggestions. I love these forums. The best I've come across.

Pete

I've been doing a lot of thinking over my holidays and I'm now leaning towards a alloy composite monocoque. Why you ask? Well for starters it's something I've always wanted to do. I love welding which is why the back half would be a space frame. Secondly I feel if I can create a great monocoque front section with the rear as space frame I could then adapt the rear to suit different applications, for example the rear end of an F3 car, engine gearbox etc, all bolting to the monocoque.

I've read up about the designing and construction of a monocoque and have come to the following conclusions:

Monocoque will be the same price as a space frame (chromo) - remember space frame was also have stressed alloy panels
Monocoque won't suffer from distortion like a welded space frame can (not to say spaceframes always distort, but containing this distortion can be tricky)
Adhesives can be very messy and expensive.
Monocoque is hard to repair.
Monocoque has less pieces so could be much easier to manufacture.
Monocoque can accept wider range of drive lines.

I'm open to all comments, suggestions, criticisms and more!

Here's another update. I have reworked the chassis and simplified the rollover protection and simplified the dash/rollover section too. I have been thinking about ways in which to stiffen the cockpit. A lot of sports racers use braces coming down from the roll bar to meet along the cockpit sides but I've never liked this solution. I have been toying around with the idea of building a carbon fibre tub within the chassis structure. It would be like a moulded 2 person seat bolting in at various points. More research needed.

The bodywork has once again changed and after lots of advice on this forum has been somewhat simplified so that it's more predictable and easier to manufacture. Still some way to go here but definitely getting close.

I have also added in some basic steering along with the differential unit, a radiator position and a basic exhaust (exiting under the car - blown diffusor).

Those braces are required by their rules. The extra tub idea sounds heavy. If you want more stiffness it comes from integrating the design of the frame and body better. Not sharing the loads, but arranging the shape of the body and then using the space provided for frame. The upper frame rail is the one used to prevent twisting thru the cockpit section. You can raise it ( yours is high already ), increase it's section, change it's section to rectangular on it's flat side or build truss inside or outside of it.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
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Bovax I think you had better read a rulebook before you go further and pay attention to "the broomstick" test too - that's a broomstick that touches the top of your rear roll bar and your front roll bar and doesn't touch your helmet and they do literally use a broomstick for the test.

CAMS are pricks for giving out info for free but the SCCA website is a good source but then Americans actually encourage and support racing for their members ...

Thats some great modelling there! Why are you running such aggresive anti-effects in the suspension?

Thanks for all the great feedback, especially about the chassis. It's obvious I need to do a lot more reading. With regards to weight with the internal 'tub' this will actually be the interior of the car, so the seats, dash etc. I imagine it would be created in a way that added stiffness and not a lot of extra weight (using a carbon/composite mix). I am glad I've got some people commenting as I am still new to the engineering side of things and I have a long way to go.

With regards the the anti effects how much is too much? I have added in this anti after reading a lot on suspension design and my thinking was that this was the right amount. Have I misinterpreted something? Will there be a lack of feel through the front end under brakes, and a perhaps a lack of traction under acceleration with this set up? Or is that all too hard to tell until I have actual C of G figures and the like?

In my earlier chassis designs I had taken the broom handle into consideration and I'm aware that with this current design I'm going to have to raise the dash bulkhead in order to pass. Can anyone else see anything glaringly obvious?

I wish y engineering was as good as my modelling... that's what 12 years doing graphic design and a only a short time reading race car engineering books does to you.

Not many race cars use anti anything in the geometry other than a little anti dive sometimes, many consider it "anti suspension" which is exactly what it is as the forces that stop the suspension compressing also stop the suspension working freely over bumps and that's a bad thing on a race track.

I would recommend you pick up a copy of Think Fast by Neil Roberts, he gives some good advice on suspension geometry selection, particularly Chapter 14: Geometry Goals.

http://www.amazon.com/Think-Fast-Racers ... 1451558759

(no connection to author, etc., just a great book)

With this type of car anti-effects are not needed. Your centre of gravity should be so low and your suspension motion ratios so small there is no need for anti-dive or anti-squat.