Question about under car aero & diffusers

[roost89]

When reading this I remembered about these images:

It appear as if the underside is clean and they have covered the sides up. It seems they havn't been able to do anything else (apart from fit wings)

Hopefully that helped...even a wee bit

[dp35]

Actually, the bottom is very much not clean, aerodynamically speaking. As you can see in the photo below of the bottom looking front-to-back, the front firewall is like an exposed wall for the air to hit, and it doesn't get much better as you move rearward.


This photo shows how I modified the bottom at the front, by installing a flat piece. I have a track day next weekend, so we'll see then if it makes any difference. I'd like to have side panels installed by next weekend too. Later, I'll work on flatening the rest of the bottom.

[zac510]

Wow we have action already! Looking good - keep us informed with how it goes.

[Conceptual]

Looks good!

But, what are those tubes that go down the center of the chassis? My only guess would be an intercooler since it is a rear engined car with the air intake through the roll hoop.

I can't for the life of me figure out what those tubes are for!

Chris

[modbaraban]

Those are shassis components, I guess.

[Conceptual]

Those are shassis components, I guess.

Maybe coolant send/return to the radiator?

I don't think that they are chassis components, or they would not have rubber connectors, right?

Chris

[dp35]

That's right, those are coolant lines. The radiator is at the very front.

[yzfr7]

@dp35
From what I understood, you want to create a diffusor, but as you said you don't have much space up (the chassis is right there), you want to increase the area by going wide.

But the idea is to make the upper and under parts of the body be as close as possible at the rear, so the vortices will be weaker, thus less drag. Just as if your whole bodywork was an airfoil.

Just check the LeMans prototypes so you can understand of what I'm talking.


Also, I don't quite get how you would make it wider, as the tyres are right there too.

The flat underbody seems good.

[The FOZ]

Were I in your position, I'd start with a CAD model of the car's rough shape and contours, so as better to design the bodywork you'll be needing. Obviously the first place that needs work are the structural elements along the sides of the unit...I think some .050 Aluminum is about all you'd need to do the job. The underside can be improved if only to reduce vortices - I don't quite see how a car that light and well suspended really needs a ton of effort put into downforce.

From there...it's gonna be the sum total of the work you do that will make the really big difference...taking a given section of the car and finding ways to allow smoother air passage, that's the name of the game.

[modbaraban]

@dp35
From what I understood, you want to create a diffusor, but as you said you don't have much space up (the chassis is right there), you want to increase the area by going wide.

But the idea is to make the upper and under parts of the body be as close as possible at the rear, so the vortices will be weaker, thus less drag. Just as if your whole bodywork was an airfoil.

Just check the LeMans prototypes so you can understand of what I'm talking.
http://www.infoscourse.org/2006_ALMS/Po ... der_00.jpg

Also, I don't quite get how you would make it wider, as the tyres are right there too.

The flat underbody seems good.

Perhaps this close up pic of the RS Spyder's diffuser I made a few months ago at a motorshow can be helpful.

http://f1world.kiev.ua/gallery2/main.php?g2_itemId=5014

[Scuderia_Russ]

Does this car have adjustable front and rear roll bars?

[ISLAMATRON]

any updates?

[dp35]

Not many updates on the aero package so far, and I have not built a diffuser. Been focusing my efforts on getting the ideal alignment settings to maximize mechanical grip. I now have a Traqmate GPS datalogger, so I can test changes & compare the results with real data.

I did try out some plexiglass sides to clean up the aero. This was just one test and the results were inconclusive. If they help its only a small amount, much less than expected.

I recently entered the Atom in a race (video link below). This was just a fun race as part of a track day event. There were 28 cars in the field, including Miatas, various Porsches, a Ferrari Challenge Stradale, 2 Trans Am Corvettes, a Formula Mazda, etc. Although the 2 Corvettes and the FM had faster best laps than me, I was able to steal the victory by 0.04 seconds.

Video: http://www.vimeo.com/5277350

[ISLAMATRON]

outstanding

[scarbs]

You'd need to create a totally new underfloor, the diffuser couldnt start until the rear subframe ends this would pushthe downforce more rearwards, assuming you'd want a more neutral aero balance, then your going to need to add a splitter towards the front.

I'd suggest a new underfloor, with the front egde being much wider than the chassis and somewhere behind the front axle line (see pics). The position of this leading edge will need to be experimented with, in order to get the right balance. The forward section of floor could be made of plywood, making it cheap and easy to modify. Also skin the floor ahead of the splitter, but maintain a height diffuser between the two to keep the splitter effective. lastly Add a section of floor either side of the diffuser to act as a footplate to seal the low pressure.

Adding skirts underneath or fences within the diffuser would be a second stage to develop. As would tighter control of ride height and roll.


High Res http://www.scarbsf1.com/Atom.jpg

Scarbs