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Old 11-26-2014, 01:28 AM   #581
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well, if the tunnels extend further foward into the undercarriage, a larger AOA can be achieved. The volume isn't necessarily reduced, depending on the shape of the tunnels vs. the shape of the diffuser. Furthermore, the downforce created by the tunnels will bring the CoP closer to vehicle center.
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Old 12-02-2014, 04:58 AM   #582
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This popped up on a FB page about prototypes and such, not sue if it would be better to transplant the info into its own thread or put it into this one. But NACA ducts vs Scoops:

NACA Duct vs. Scoops | Ivanitski
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Old 12-06-2014, 04:36 PM   #583
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So has anyone wondered why the designers of a supercar that isn't bound by homologation regs opted for a spoiler and winglets instead of a main wing element?

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Old 12-06-2014, 05:34 PM   #584
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Their marketing department said it looked cool.
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Old 12-06-2014, 05:53 PM   #585
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Visibility out of the rear view mirror?
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Old 12-06-2014, 08:21 PM   #586
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The rear diffuser looks too steep to work as well. Maybe it is just built to have fun in.
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Old 12-06-2014, 08:46 PM   #587
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Rear hatch/engine cover wouldn't clear the wing?
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Old 12-06-2014, 09:42 PM   #588
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Wing vs spoiler. I'll just leave this here for discussion. (blue is turbulent, red laminar)

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Old 12-06-2014, 10:05 PM   #589
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Blue is not turbulent. Red is not laminar. And those are two different generations of cars with two very different front ends.


Red is stagnant. Blue is rapid.
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Old 12-06-2014, 10:54 PM   #590
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According to the article it says red is laminar. But it wasn't the most technically written aero discussions.

Wings/Spoilers: You're probably doing it wrong.


I was looking more at the comparison of spoiler vs wing which the change in front end shouldn't effect to much.
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Old 12-06-2014, 11:15 PM   #591
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Quote:
Originally Posted by Leafy View Post
Their marketing department said it looked cool.
Quote:
Originally Posted by SchmoozerJoe View Post
Visibility out of the rear view mirror?
Quote:
Originally Posted by Supe View Post
Rear hatch/engine cover wouldn't clear the wing?
I know these are half sarcastic, but also things that might actually affect design inputs. However, I'm going to take Ferrari's word that they built this car purely for low lap times.

What reasoning could they have? I haven't seen the under tray, but I would guess it's using ground effects to full advantage. The old F1 cars that ran ground effects still ran a large rear wing element. Is it possible that, with advanced CFD, Ferrari has found that ditching the wing and optimizing the chassis as an air foil can actually make more downforce? Or, what I think is more likely, have they found a middle ground where there is a little less down force, but a lot less drag?

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Wing vs spoiler. I'll just leave this here for discussion. (blue is turbulent, red laminar)
This has nothing to do with aero. Its all about NASCAR regs that were introduced to slow the cars down to make them more safe.
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Old 12-06-2014, 11:50 PM   #592
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Quote:
Originally Posted by mx5autoxer View Post
This has nothing to do with aero. Its all about NASCAR regs that were introduced to slow the cars down to make them more safe.
To me it is a valid aero discussion. Personally I am deciding between spoiler vs wing for my car. But I think that comes down more to a cost thing in the end.

If I recall correctly NASCAR kept the spoiler because the wing caused lift if the car span out and was traveling backwards increasing the likelyhood of a flip. But for our cars we still have the option to run either.
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Old 12-07-2014, 04:25 AM   #593
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On an F1 car, upwards of 50% of the downforce can come from the underbody/diffuser, and that is with significant limitations on what they can do. An unrestricted car built around the most effective floor/tunnels their engineers dream up could produce incredible downforce without the use of relatively high-drag elements like conventional wings.

-Ryan
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Old 12-07-2014, 10:21 AM   #594
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Ferrari isnt going to sell a car to the public that makes the majority of its downforce from under effects. Its exceptionally dangerous, see the lotus 79; kerbing, dips, and other surface imperfections were a good way to find yourself spinning off into the armco after loosing the majority of your downforce. Its the reason limits got put on under body aero in F1 back then.
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Old 12-07-2014, 02:14 PM   #595
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I said "could"
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Old 12-07-2014, 04:42 PM   #596
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Quote:
Originally Posted by Leafy View Post
Ferrari isnt going to sell a car to the public that makes the majority of its downforce from under effects. Its exceptionally dangerous, see the lotus 79; kerbing, dips, and other surface imperfections were a good way to find yourself spinning off into the armco after loosing the majority of your downforce. Its the reason limits got put on under body aero in F1 back then.
Given that any FXXK buyer will only be allowed to drive it on approved racetracks under the close supervision of Ferrari's support crew, I tend to agree with ThePass that it's likely the majority of the downforce is going to be from the underbody. Dangerous isn't part of the equation, because Ferrari probably said so. As such, it'll be sooner rather than later we see pics of totalled FXXK's because they hit a bump.

As for its diffuser geometry; it's very likely its throat expansion geometry is well sorted via CFD and wind-tunnel. It's probably much more laminar than it looks from that picture.
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Old 12-07-2014, 07:07 PM   #597
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Quote:
Originally Posted by Ryephile View Post
Given that any FXXK buyer will only be allowed to drive it on approved racetracks under the close supervision of Ferrari's support crew, I tend to agree with ThePass that it's likely the majority of the downforce is going to be from the underbody. Dangerous isn't part of the equation, because Ferrari probably said so. As such, it'll be sooner rather than later we see pics of totalled FXXK's because they hit a bump.

As for its diffuser geometry; it's very likely its throat expansion geometry is well sorted via CFD and wind-tunnel. It's probably much more laminar than it looks from that picture.
I was thinking the same thing. This isn't for the highway cruises in California.
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Old 12-08-2014, 03:06 AM   #598
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Re: FXX K Aero

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The front of the car is dominated by a twin-profile spoiler and a larger splitter, which is 30 mm lower, with a gap in its centre. This design is an application of the concepts developed to improve aero balance in the GT category of the WEC, which Ferrari has won for three consecutive years. Two pairs of vertical elements, an endplate and, externally, a dive plane, together with vertical fins channel the air towards the car’s flanks, generating a longitudinal vortex that creates a localised depression. This in turn sucks the wake from the wheels to the outside of the aerodynamic underbody. Along with the side skirts that extend out from the sills, the vortex helps isolate the airflow from the underbody to boost its efficiency.

The solutions on the rear of the car are highly sophisticated, too. The tail section is now higher and the mobile spoiler extends further for a total increase in extension of 60mm when fully deployed. A vertical fin and a small wing each side of the tail act as guide vanes in the low drag configuration and boost the spoiler’s efficiency in the high downforce one. This system also creates considerable downforce at the rear of the car, allowing the use of an extreme diffusion volume for the rear diffuser which optimises air extraction from the underbody. The section of the flat underbody just ahead of the rear wheels is also exploited to the full to generate downforce thanks to the reduced pressure in the wheel arch guaranteed by the direct connection to the rear of the car by a by-pass duct.

The result is a 50% improvement in downforce in the low drag configuration and a 30% improvement in the more aggressive downforce configuration, resulting in a figure of 540 kg at 200 km/h.
source: Axis Of Oversteer
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Old 12-08-2014, 04:18 PM   #599
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Why if not regulated would you not go with active aero or something like an Aeromotions active wing?

Aeromotions | makers of the world's finest carbon fiber wings and spoilers.

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Old 12-09-2014, 05:26 AM   #600
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Well it's not very TOP SECRET now is it!!!
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