F40 rear air fence?

This adjustable flap?

Standard application on all F40 LMs, useless for the road (unless you count the poseur factor), its a crude down-force aid.
Image Unavailable, Please Login

 

Still looks damn hot I tell ya

 

Air Dams, Gurney Flaps, Strakes, End Plates and Winglets are aerodynamic tuning devices. Wings on Aircraft because of their differently shaped upper and lower surfaces create pressure differentials that cause lift, or as Newtonian Physicists put it the wing pushes air down and the equal and opposite reaction causes the plane to go up. On cars these devices are inverted as the desire is to foil lift and create downforce. Airplane wings have movable surfaces on the trailing edge of their wings called flaps which have the great advantage of being able to be cranked down to increase lift at low speeds and enable an aircraft to land safely without aerodynamic stall. Cars don't have the advantage of Cockpit controllable movable flaps. Dan Gurney realised this and bolted an angled piece to the trailing edge of the rear wing to improve downforce. This Gurney flaps works very well at low/road speeds. The 8C has a very nice one bolted to the front underside for this reason. End plates and Winglets have a different function. They reduce wing tip vortices's which induce drag. The reason you don't see Gurney Flaps on street cars is not because they don't work at low speed, like their equivalent on aircraft movable flaps, they help a lot at low speed but they don't meet motor vehicle safety standards as they are sharp edged and can inflict wicked cuts. Never run your finger along the edge of one with any force. They're allowed on the 8C only on the underside of the car where a pedestrian can't come in contact with them.
Image Unavailable, Please Login

 

Those darn poseurs...
Image Unavailable, Please Login

 

You're right! All those dams, flaps, strakes, plates & winglets on road cars which are supposed to be operated at various speed restrictions between 45 mph or 65 mph will help you win more friends, and become popular with the ladies!

As these diagrams show, these appendages (which are illegal in most instances on a road car) will ensure better down-force thereby ensuring you don't leave the road due to lack of adhesion on the way to lunch at a club meet

Gurney flaps are really a competition application.
Image Unavailable, Please Login
Image Unavailable, Please Login

 

Yes I see and it really is a competition application so for a car driven on the road one can be excused for concluding that a certain degree of posing is taking place... this one isn't even adjustable as the ones which are used on full-blooded racing F40 LMs are. How does it contribute to a car driven on the road at legal speeds? Id say it is merely a visual application of no handling significance whatsoever...
Image Unavailable, Please Login

 

Small aerodynamic devices can have very meaningful effects. That particular fence tunes the engine compartment exit air flow for better engine cooling. Note the engine compartment exit vents directly in front of it.

http://www.ferraris-online.com/pages/imgview.php?reqcardir=FE-F40-90568&imgnum=P005

It creates a low pressure area behind it which causes air to try to fill that void and flow faster through the engine compartment.

Here's one that's used on the 8C to decrease nose lift.
Image Unavailable, Please Login

 

I wonder if it would work on people, Jim.

Fence creates an area of low pressure behind, as you said Jim. Fences are used also to channel air around drag producing components, and capture boundary layer above and below many cars, even mundane ones.

Dearest Joe, do you tell your clients stuff like that, or just snicker while you cash the checks? I just want to be clear which dogma holds in this case.
Perhaps I and Scuderia could have you visit us for a drive to a club meet, we're known for them. You could give a talk on aerodynamic engineering and useless appendages...speaking of which-
I thought RB aviators belonged in the 80's. At least the Miura has a toolbag, many don't.
Image Unavailable, Please Login

 

If road legal speeds were all that car designers were concerned about, there would be no need for the large wing at the back of the F40 let alone the little flap. They could also have put a 100hp econocar engine in there and be done with it.

The F40 is capable of 200mph and yes at 125mph+ the various aero devices play a key role. Don't blame the aero device for the lack of guts of the owner to use them.

 

now now, don't start a fight with a "sponser" you'll be banned quicker than you can say "Roy Catz". Besides no one actually puts their car on a track, nor even drives them around here, we all just like to rub them with a diaper and talk about the values. Don't you know anything?

People like Joe put the ">agina" in ">aginaChat", no worries just watch and laugh

 

I dunno, Wes. There ain't many things greater than an agina.

 

thanks, I just spewed my coffee over the keyboard....LMAO

 

Oprah has an agina too....its a matter of perspective.

 

Sfumato:

I must apologize in advance for revealing to you that the photo which you purport is a representation of me, has in fact been photo-shopped. At my age I would give my right arm to look like the photo suggests, but the sad truth is that I am short, fat & ugly.

Furthermore, the dark glasses that I am wearing (I have figured out now that these are the so-called RB Aviators you speak of, something I did not know) are one of worst items I posses, such because they are uncomfortable & ineffective. But I wear them because my wife - who ordinarily has great fashion sense - gave them to me commenting that they looked good on me and that they were timeless. Clearly she lied. I will amend the error of my ways and dispose of them forthwith. Meanwhile please advise what the current brand & make of cool shades are so I can remedy the situation.

Regarding the Gurney flap: Dan Gurney is my neighbor here in OC and he tells me to say that you guys are wholly correct and I am completely wrong. The device is for the street, and not for competition application. Then he burst out laughing - I have no idea why. At any rate, how could I have been so silly? Apologies again.

I have noticed that you are rather concerned with my clients. You should be. This is because I have not yet managed to master the eloquence of dialogue or bedside-manner that you bestow upon your patients that leaves them saying only great things about you. In fact, I gather that they are all happy campers! My current problem is that my clients (the real clients, not the poseurs) are so upset with me that they keep writing nasty letters and telling my webmaster to post them, which he does without my permission! I am posting a selection of them in the hopes that you can give me some pointers. Please feel free to post yours so that I may learn what you do that makes your patients so happy.
http://www.joesackey.com/Testimonials/

I appreciate your concerns thus far and I thank you for sharing them.

Best,
Joe

 

As Dan Gurney said to me one time, "Who are you?"

 

The good thing about Dan, is that when confronted with the fact that he didn't invent this device, he acknowledged it.

"Gurney, meanwhile, had allowed McDonnell Douglas in on the secret and was given access to an old wind tunnel in which to test it. Measurements on the test wing showed that fitting the Gurney Flap affected pressure across the wing's entire upper and lower surface, increasing lift (or downforce) and reducing flow separation on the wing's suction side. Gurney placed the patenting of the device in the hands of McDonnell Douglas and, for some years after, AAR cars used to carry 'Pat Pend' scripts on their wings.

This patenting effort, however, eventually came to nothing, not least because one Edward F Zaparka had patented a similar device as far back as the early 1930s. As Dan wryly pointed out when he faxed me a copy of Zaparka's patent, it was originally filed on 3 April 1931 – exactly 10 days before one Daniel Sexton Gurney was born."

 

That is interesting about the 8C. Wonder why more cars don't have this?

 

All 997 GT3's come stock with a gurney flap on the lower of the two rear wing surfaces. Easiest to see on photos of white GT3's. The one on mine seems to be made of a hard rubber material, not too sharp on the leading egde. Looks cool, not sure if it does anything, but I suppose it can't hurt either and unlikely the P-car engineers would have put it on there unless it added value.

 

The issue is your inability to accept the concept you could be wrong. Even when presented with evidence, which you dismiss, no matter what the source. You inconsistently use logic from thread to thread as it suits you, yet you gavotte in every corner of this sub-forum.

I don't care about your clients. Never have. Narcissistically comparing a used car dealer CSI to a physician's CSI is pathetically laughable. (mine is fine, but health information is covered under the Privacy Act, 5 USC 552(a), Health Insurance Portability and Accountability Act, Public Law 104-191, and DoD Directive 6025.18.). I had a nice comment on a site I was directed to on the "waiting at doctor's office" thread. It and a bunch of others were up for several years, I never saw them. The comment that was most touching was from a family whos child died, which happens in my business. The fact that they posted it while grieving their child stunned me. Guess one of us will be remembered longer than lunchtime.

Jim, Peloton, a couple other owners (not poseurs) have pointed out you are wrong. With pictures and words. I just enjoy watching a narcissist prove repeatedly how knowing concrete data (ie vin histories) has little to do with the design intent and purpose of a car, nor the principles behind same. Even NNO knows that.

I typed this slowly so you can read it and still have time for one eye in the mirror. Nice to have someone always think you're right.

PS, give Mr Gurney my best. Met him 25yrs ago at the historics, Ford year. I expect Jim knows him too, with J6 and all. Gurney bump was his, flap no. Dan didn't need the bump for his ego, just his helmet.

 

cool, this weeks "holy grail"...once it sells, on to the next "holy grail"...and so on...and so on....

 

tell us then oh great one, how many "holy grails" have you found this year, last year or how about ever ?

didnt think so.

 

Yes exactly.

DM18

"That is interesting about the 8C. Wonder why more cars don't have this?"

They do as Lee pointed out. Keep in mind that this device was invented to "reduce landing speeds" by increasing lift at lower speeds so it's actually very useful at lower landing speeds in airplanes and lower road legal speeds in cars in smoothing airflow in the F 40 Mike is offering in the photo referenced by Scott.Mac and creating down force in cars, lift in airplanes, remember on cars the device is inverted vs airplanes. If you read the Engineering Papers from 1932 you learn that the device's effectiveness at low speeds was the main point of the device. It enabled the development of "Short Landing Short Takeoff" airplanes which was very important to the ability to take off and land on aircraft carriers as it generated Lift/Down force quickly at lower speeds enabling aircraft to take off sooner and land shorter.

Note the moulded in aerodynamic fence on the trailing edge of an SUV's rear aerodynamic device in the photo below.

It's interesting that the aerodynamic fence that peloton spoke of on his Porsche, through excellent engineering has been made pedestrian safe.



"Zap development is a successful effort to reduce
landing speeds without impairing high speed and
thereby bring about the best overall increase in the
efficiency of a aeroplane with the least added complications
Experimental work on the Zap flap was preceded
and stimulated by investigations on a Flettner
rotorplane by Mr. Edward F. Zaparka."
Image Unavailable, Please Login