I Finally Discovered The True Answer For The Purpose Of The Rear Wing On QV's

So your saying I’m actually a pilot, sweet!

 

That's a great story. I ain't buying it. As I said in the other thread. It simply could not function the same on a GTS with the roof panel on and off. And, it it were to be functional there wouldn't be different surface treatment, textured or smooth, as that will also effect aerodynamic performance. They had to name it something. The might as well have called it "tavola del tetto posteriore".

 

It does actually do something... However when I ran the CFD it only became noticable from 80mph and up!
Reduced the low pressure zone on the roof and reduced the drag off the engine decklid.
Below 80mph.... Meh...

 

Is this the one to which you are referring (rear of roof in photo)? As I've read elsewhere, they were either black or painted body color.
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Im sure it works well at 80- 150 MPH , I have 4 winglets on my Ducati V4S that produce 60 lbs of down force at 160 MPH, much less of a surface area on the bike compared to the wing on the 328 . I have no doubt that it creates down force at speed, how much, who knows, they are pointed upward on the 328 , Im sure they are functional. non the less .

G

 

And did you simulate the GTS with and w/o roof panel in? Did you consider the rear deck vent configuration and differences between vent configuration for cat and none cat cars? Did yo consider the flow under the car and the flow through the rear deck vents? Was it a 3 dimensional simulation?

You could take apiece of 1/2" plywood and screw it on to the rear deck and it would do something. None of that means it was the intended purpose.

 

3D yes, no on the gts top on/off. The purpose was for a lower diffuser panel I designed for a project. There's a couple old threads out there on it.

 

No idea on the intended purpose... Didn't really care.

 

I think they do little to nothing on the 3x8 cars and were a cool-factor carryover from the 512's. However, on the 512's, they actually did something.

I'm not a 512 expert so for those of you that are, you can probably call BS on my theory. But on many of them, they had two rear louvers that faced forward. I suspect that on those cars, that wing (or aileron) diverted air down into the intake. Almost like a cheap-man's forced induction.

Just a theory.


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Agreed.

 

My gut feel after reading what you wrote is that it's a bit of a stretch, and that particular part I quoted above is really the kernel of it. There is a pretty big chasm between "flap on engine hood" and "Ferrari felt it gave some added stability to the car at speed". It's not a logical leap to make without some technical documentation.

Even if it was purely cosmetic, "flap on engine hood" would still be an apt description. There are so many cars with options like "rear wing", "deck spoiler", "rear diffuser", "winglet"-- all very descriptive aerodynamic effectors -- that use them purely for styling and cosmetics. I think rear diffusers are the most recent styling fad to steal aero terminology, but if you look at most of them they are nothing like the real thing.

 

Calling it an aileron (from a google translation) doesn't mean it actually serves any function as an aileron. There is still no evidence of any testing or whatever by the factory that demonstrated that the 3x8 wing was needed for any purpose. AND... It still comes down to: WHY was it an option if it was functional? THAT is still, to me, the ultimate indicator that it was simply cosmetic.

 

Dr Tommy,

Well ; not wanting to start the debate over the purpose of the roof spoiler, but only from a langage perspective...

As for the roof spoiler, or dare I say : « aileron de toit », which is its actual french name...
We should first and foremost take into account that « Alettone » might actually not be totally related to the french « aileron », nor signify exactly the same thing :

• it might actually well be that « aileron » comes from « alettone », as Greek and Latin are the main source of the french langage (in that order)...so perhaps, if the italian word predates the french word and inspired it, we should discard the french word entirely and start from the meanings of « alettone » only ( ?).
  
  
• there are a few « falses friends » in french and italian (one of the most often quoted is « primavera » in italian and « primevère » in French : the italian « primavera » is « spring » (season) the french is a flower that grows in spring, but spring itself in french is « printemps »...traps that any Frenchman studying italian, or Italian studying french is warned about.

so caveat here, we should ask an italian about « alettone » before.

That being said...as a french speaker, your analogy could be right, but it is incomplete as it only takes into account one of the meaning of the french « aileron », which has at least four that I am aware of :

Zoology : actually, the first and original one : some fishes’ fin(s), usually one that does not help swimming (for those you would use « nageoire » (= « swimmers »)) but whose purpose is essentially stability (= not a rudder, but only a fin) exemple : « ailerons de requin » translates into « shark’s fins ».
The tip of a bird’s wing, in some cases, is also called an « aileron ».
By extension, modern use : the finlets that are under a surfboard, and whose purpose is not directional (not movable, not a rudder) but stability, are also called ailerons as they looks like shark fins.

Architecture : in baroque architecture (= XVIIIth century, more or less), an « aileron » is a part looking like a turned-over console, which purpose is only aesthetical : maintaining visual continuuity between two other decoration registers, or two stories that have a different width.

Aviation (circa 1910, when torsion/flexion of the wings was abandoned): a part of the wing, usually at the rear of the tip of each wing (usually : some aeroplanes do have ailerons closer to the fuselage) that moves in opposition from one wing to the other (if the left one goes up, the right one goes down) and produce a roll moment.

Automobile : any body part, or part fixed to the body, which looks like a wing (even remotedly) ; might have an adherence purpose, might have a drag reduction purpose, might have a visual purpose, or any combination of the three, or...none at all.
Befitting also the original zoology, note that it might also be horizontal or vertical : the big fins on some ‘50s Cadillacs are also called « ailerons » in French...

I woulnd’t draw any conclusion from the french word « aileron » to the actual function of the 308 « roof spoiler »...
Besdies, for any « ricer » cars with lots of flippers here and there, most of these useless, you would also call these « ailerons »...tongue-in-cheek of course.

Rgds

 

Uh , yeah...just what I was thinking!



Hmmm...wonder if the ailerons on a Boeing 787 are optional?

 

"Alettone" in Italian is every rear (or front) wing attached to a car and bolted to the car body. If it's part of the car body, it's called "spoiler" even if it's an English word. Alettone it's usually translated in English as "wing" who is "ala" in Italian: "ala" is another Italian word you can use instead of "alettone": the meaning is the same (if you are talking about cars).

The word "alettone" is used also to identify airplanes vertical control surfaces: in this field alettone and ala are two very different things and no more the same like it happens telking about cars.

Formula 1 cars have a front and rear wing (= "alettone" or "ala" in Italian). "Alettone" or "ala" are devices who produce vertical load. 308 and 328, 208 turbo and so on haven't any "rear device who produces vertical load": Ferrari called it "alettone posteriore" as it reminded that to the public, but it's a bit a commercial exageration of a very simple surface who only reduces a bit the vortex behind the roof, so it's a (very small effect) drag reduction device. Its purpose is like to have a ten inches longer roof.

Sorry: it's much more aesthehic than a real effect producer.

Another thing is the front "Spoiler maggiorato": it does improve car stability at very high speed, by removing air from below the car and so reducing front axle lift at high speed.

Ciao

 

So we do have a few differences here between the italian "aletonne" and the french "aileron", and that doesn't surprise me.

In french and aeronautics, "aileron" is only the roll control surfaces, and nothing else. "Aile" (= wing) is only for the part that provides lift, or the "main plane" in English.

The horizontal part of the tail (for aeroplanes that do have one, "Deltas" do not...nor do aeroplanes with butterfly tails, etc...) is "la profondeur" (= depth) with the non-movable part being "plan fixe de profondeur" (fixed depth plane) and the movable one (which moves the airplane up & down) being "gouverne de profondeur" (more or less "depth rudder")

The vertical surfaces of the tail are "dérive" (= fin) for the fixed part that is fixed, and "gouvernail" (= rudder) for the part that moves and directs the plane.
(Well actually, as every pilot knows, the actual use of the rudder depends from one aeroplane to another, as some aeroplanes do not require as much rudder as others for turning, turning being usually obtained by a combination of roll control and "some" rudder, at least at the start)

Rgds

 

And, as Alberto's contribution shows, "Alettone" in Italian covers slightly more meanings than the french "aileron"; the italian "alettone" can means a little wing in aeronautics, if my understanding of his post is correct, whereas in French aeronautics, aileron is strictly restricted to the roll control surfaces...in automobile terms, it seems that French "aileron" and Italian "alettone" are close in their meanings.

Rgds

 

Yes, you are right, thank you for posting: old documents are always welcome! There were (a part) of official Ferrari options and prices also on old Quattroruote Italian magazine of the age. I think I posted here some pictures of the option price list several years ago and I will post again as soon as I will remember to do it. But you have to consider that Ferrari had a very clever marketing department who studied the best way to describe their cars: that was the reason of the 255 HP @7700 RPM of the carbed 308 (a fake, as 7700 RPM were the rev limiter setting and not the max power RPM, who was around 6600 and the 255 HP were measured without muffler, without air filters and with the waterpump and alternator disconnected from the engine and moved by an external power source...) and of that 308 roof air deflector who officially became "a very effective aerodynamic device" who was much more a very nice design feature who modernized an old shape introduced in 1975...
Words who come from a friend who was at Ferrari tech department since 1966 an then became the GT engines department boss.


Ciao

 

I had sort of the opposite reaction - i know exactly what an aileron is, in terms of aviation - no dictionary needed. I believe in this case, it's just a matter of picking a word that may be familiar to someone in a particular language. The part itself has nothing in common with an aircraft aileron, except that it's sort of flat. It certainly isn't a control surface.

Note that many cars (in general) are described as having a rear "wing". It's not comparable to a "wing" in any other regard, as wings generate lift. On an F1 car, the whole point is to decrease lift, not generate it. So it's more an issue of nomenclature, not an accurate description of the intended behavior.

Let's remember the Countach, with the front wing. It certainly had a purpose, but it wasn't aerodynamics. It was to raise the bumper height to meet import rules (a clever way of technically meeting the standard, one might observe.) It also had an optional rear wing - I've no idea if it did anything, other than make the car look even more ostentatious.

As to the whole question that some raise on, "If the 308 wing/spoiler/thing DOES do something of value (or was intended to), why was it optional on some cars?" Heck, air conditioning was optional on cars back in those days. So were stereos, power windows, door locks, and fog lamps... all of those things have a function. Automatic transmission vs manual was an option - both have a function. Other features such as pinstripes, chrome-tipped exhausts, useless vents in the side of the car - also options, that did nothing. So we can't really draw any conclusion on "Present vs Not Present on every car = Useful vs Cosmetic."

I've no idea why it's on the 308. Maybe the 308 team thought it had actual performance value on the BB, and just slapped it on with (or without) testing it. Maybe the marketing dept thought it looked nice, and demanded it get one.

Fun info from the Ferrari archives, no doubt. I personally don't think it really answers the root question, but I'm also fine not really knowing the answer. I get far more annoyed hearing about Magnum PI every time I drive the car, than not knowing why some 308s have a rear wing.