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Are flat under-bodies marketing hype???

Discussion in 'Ferrari Discussion (not model specific)' started by need4speed, Sep 1, 2004.

  1. need4speed

    need4speed Formula 3

    Nov 3, 2003
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    I noticed that the bottom of my Dino is just as flat as any current "mega-downforce" "sucked to the ground" Fcar. The only exception is the diffuser out the back. So if flat under-bodies have been around since 1970, then why does it sound like a recent discovery? Is it just marketing hype trying to make something old sound new?
     
  2. seinfeld

    seinfeld Formula Junior

    Jul 6, 2004
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    i highly doubt that it is marketing hype. I think most of the ferrari's and lambos have the flat underbodies for the air to slide through to create down force....like the le mans cars...

    do you really want to buy a $100k racing tuned car with no aerodynamics?....if so...then just get a Scion XB..(no offense intended)
     
  3. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
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    Your car is flat, just flat, except under the motor area which was left open. That was done to reduce drag and provided no down force. If you look under a 360 or an Enzo it is not flat and is completely enclosed. The shapes are to not only to reduce drag but to also provide down force at speed. Both of those and other late model Ferrari's spent a great deal of time in the wind tunnel to get those subtle yet very important and effective shapes right.
     
  4. Jordan Ross

    Jordan Ross Formula Junior

    Nov 4, 2003
    591
    Austin
    Of course this is not hype.
    The flatter the bottom of the car, the faster the air can flow under it, and the less drag pushing on the car. It also reduces road noise from wind. Sometimes the borrom rear of the car will curve upwards (especially visible on the 360CS and Enzo), this lets the air flow up and creates a low pressure zone under the rear of the car, which sucks the car to the road. Its called downforce, and is the key to good traction at high speeds.
     
  5. smsmd

    smsmd Karting

    Nov 12, 2003
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    Steven Scates MD
    It's not hype.

    The flat undercarriage serves 2 purposes. First, it takes quite a bit of energy to move the car if the mufflers, etc, catch and hold air as the car speeds up, since wind resistance increases with the square of the velocity of the car. Second, Bernoulli's principle says that the faster the airflow, the lower the pressure. This means less lift. By using aerodynamics to produce vortices under the car, the speed of moving air can be increased even further, resulting in even more downforce.

    steve
     
  6. b-mak

    b-mak F1 Veteran

    But the Dino doesn't have the front and rear aero tricks that modern cars do.
     
  7. seinfeld

    seinfeld Formula Junior

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    no offense to ricers....but i do see some of those "flares" in the back of some integras.....You know..that panel with the resemblence of the stradale...

    Do those serve a purpose a little?...or are they for cosmetics?...
     
  8. coolestkidever

    coolestkidever F1 Veteran

    Feb 28, 2004
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    take a guess, if you choose purpose, ur wrong. Ricer cars usually have nothing purposeful on them.
     
  9. seinfeld

    seinfeld Formula Junior

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  10. sherpa23

    sherpa23 F1 Veteran
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    Not to be nit picky but you cannot have downforce (or lift - which in the case of underbodies - is what we're talking about here) without drag. The drag is simply painstakingly engineered to be exactly what the designers require. So when people talk about reduced drag and greater downforce, realize that reduction of drag will come at a cost of downforce. I would imagine that the engineers in Maranello engineer a significant amount of drag into the underbodies in order to create the downforce.
     
  11. Ken

    Ken F1 World Champ

    Oct 19, 2001
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    The flat underbelly of my Europa is quite ingenious. Besides the normal suction it creates by speeding up the air like all modern designs, thus creating downforce, it also is open where the mid engine sits, which pushes air upwards around the engine and out the two cooling vents in the trunklid.

    The trunck and intergrated spoiler create a low pressure zone just behind the rear window, helping pull the air upwards in the center of the trunk lid while the lip spoiler puts downforce on the very rear of the car.

    Ken
     
  12. jimangle

    jimangle Formula 3

    Nov 5, 2003
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    Even the wing on the ricers isn't purposeful. If the car is front wheel drive, why is there a rear spoiler?
     
  13. ryalex

    ryalex Two Time F1 World Champ
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    Aug 6, 2003
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    On the newer cars, it is curved like an inverted wing, which pulls the car to the ground.
     
  14. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
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    Steve,

    I think you're applying Bernoulli backwards as it applies to airflow over the car. Think in terms of a wing, which is how Bernoulli really applies. It is the distance travelled by the air over the curved (longer) top of the wing that creates the low pressure ABOVE the wing. The air travels from front to rear in the same time, but travels a farther distance above the curved wing than below the flat bottom. Thus the "speed", front to back is higher above the wing than below, creating a low pressure area ABOVE the wing, causing lift.

    Effectively, a car would do the same thing if the air were allowed to flow both above and below the car (flat bottom, curved top, like a wing, would cause lift). To keep the air pressure lower under the car than above, designers place air dams at the front of the car to inhibit air flow under the car, thus keeping the pressure under the car lower than on top (less air molecules, lower pressure). That's what creates the down force, as I understand it. The other body modifications are to manage air flow above and around the car, and to assure that the air flows smoothly over the car and detaches from the car without causing low pressure or turbulance in the back, which creates drag.

    Have you ever driven an ordinary street car at really high speed? What happens? It feels like the car is "lifting" off the ground. The front end gets light. Look at the front. No air dam. Now look at a NASCAR racer, GT racer, etc. The air dams in front are fractions of an inch off the ground. Why? To keep the air from flowing under the car, to prevent Bernoulli's principle from causing lift.

    I'm sure Ferrari had a good reason for making the bottom flat. But making the air flow faster to suck the car down doesn't seem like the logical reason. Personally, I thought it was to keep all the stuff that is otherwise exposed from hitting the ground and getting knocked off. You often see pans under low-slung race cars to protect things from getting damaged if the car bottoms out. My $.02.

    Regards,
    Steve W.
     
  15. senna21

    senna21 F1 Rookie

    Jul 2, 2004
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    Ok, guys its real simple.

    The air flowing under the car should be faster than the air flowing above. This creates a high pressure on the top compared to the flow under the car. With that comes downforce. As it applies to an airplane wing yes the air is flowing over the top as well as the bottom. But it initially slows over the front top and then accelerates down. So, yes it's traveling more distance than the air below but it's traveling faster, creating a lower pressure. As far as flat bottoms are concerned yes your Dino and any 3x8 does have a nice flat bottom. But what the diffuser does is clean the air up as it's about to meet the air flowing over the car. It speeds it up and merges it into the airflow. The air accelerates out from under the car to fill the space in the diffuser. And no, all diffusers don't cause drag. They can help reduce it if it's designed right. If you were to look at the aero profile of your 360 it would look a bit like an upside down airplane wing. A good diffuser makes a wing on top MORE efficient and create more downforce. This is why one of the first places F1 looks to reduce downforce is the diffuser.

    The car moves through the air. Not the other way around. The air particles are fairly static in relation to the car. The car shoves its way through the air. This is way many aerodynamicists look at fluid dynamics to test cars. A car moving through water has the same effects as through air. Both are looking at moving a car through particles. Air is lighter and gives less resistance. But you can learn a great deal if you think about your car plowing its way underwater. Where is the drag being produced? How is the water flowing over those mirrors on the side? How does it fill the space behind them. How much is it swirling (drag) around?

    A 355 has a very small diffuser compared to the 360 but it's still much better than the 348 in producing downforce.

    One of the BEST sites about car aerodynamics:

    http://www.mulsannescorner.com/diffuser.htm

    http://www.mulsannescorner.com
     
  16. don_xvi

    don_xvi F1 Rookie

    Nov 1, 2003
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    Let me offer observations on a few points in this thread:

    First, the whole reason of the thread! The reason for marketing hype about flat underbodies isn't that they're some new discovery, it's that they're rare because they cost money. It shows a level of attention to detail that you don't see in many cars. It's something that differentiates a premium vehicle from the masses.

    As for my thoughts on a few random other comments:
    The wing on a ricer usually adds 5-10 lbs of downforce. At 0 mph! LOL But there's every reason in the world for a FWD car to have a rear wing if it needs extra rear grip in high speed corners, and I'd bet those rice wing kits are actually "proper" airfoil designs and CAN make downforce if you can get your 1.6L going fast enough!
    Drag and downforce (or lift) tend to go hand in hand, but the relationship between them can be optimized--designers don't dial in a specific amount of drag or any such thing, they minimze drag while minimizing lift or in rare circumstances for street cars, actually producing net downforce.
    And diffusers are indeed wonderful devices. The key to their operation is allowing the air to expand to a lower pressure as a result of their shape. This produces downforce. They require careful design to get right, though, as well as dedication early on in the design process to allow it to be fed from a tunnel that is free of other pesky mechanical distractions like axles!

    BLAH BLAH BLAH! I'm shutting up!
     
  17. senna21

    senna21 F1 Rookie

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    #17 senna21, Sep 2, 2004
    Last edited by a moderator: Sep 7, 2017
  18. senna21

    senna21 F1 Rookie

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    #18 senna21, Sep 2, 2004
    Last edited by a moderator: Sep 7, 2017
    Some neat info:

    1999 Ferrari 360 Modena
    Downforce:
    294 lbs. @ 150 mph, with 400 lbs. of drag
    424 lbs. @ 180 mph, with 576 lbs. of drag
    Lift-to-drag ratio: .73:1
    Coefficient of drag: .34 (factory claim)
    Coefficient of lift: -.25 (factory claim)
    Reference area: 1.9 meters square

    2000 Porsche 911

    Lift:
    600 lbs. @ 150 mph
    Aero. Balance @ 150 mph:
    F: 228 lbs.
    R: 372 lbs.


    2004 Porsche Carrera GT

    Downforce:
    343 lbs. @ 150 mph, with 459 lbs. drag
    493 lbs. @ 180 mph, with 660 lbs. drag
    640 lbs. @ 205 mph, with 857 lbs. drag
    Aero. Balance @ 205 mph:
    F: 192 lbs.
    R: 448 lbs.

    Lift-to-drag ratio: .75:1
    Coefficient of drag: .39 (factory claim)
    Downforce @ 205 mph: 640 lbs. (factory claim)
    Reference area: 1.9 meters square
    Calculated maximum speed: 213.4 mph (assumed 12% drive train and rolling resistance power loss)


    1991-1993 Toyota Eagle MkIII GTP

    Debut variant:
    Downforce:
    3802 lbs. @ 150 mph, with 929 lbs. of drag
    5476 lbs. @ 180 mph, with 1338 lbs. of drag
    6760 lbs. @ 200 mph, with 1652 lbs. of drag

    Lift-to-drag ratio: 4.09:1

    Twin-tiered Bi-plane rear wing development, max downforce:
    Downforce:
    5217 lbs. @ 150 mph, with 1180 lbs. of drag
    7513 lbs. @ 180 mph, with 1699 lbs. of drag
    9275 lbs. @ 200 mph, with 2097 lbs. of drag

    Lift-to-drag ratio: 4.42:1

    Daytona configuration:
    Downforce:
    3617 lbs. @ 150 mph, with 723 lbs. of drag
    5209 lbs. @ 180 mph, with 1042 lbs. of drag
    6431 lbs. @ 200 mph, with 1286 lbs. of drag

    Lift-to-drag ratio: 5.00:1
    Image Unavailable, Please Login
     
  19. PSk

    PSk F1 World Champ

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    A spoiler on the rear of a car is not just for improving traction, but cornering grip. Have a look at the British Touring car series ... just about all cars are front wheel drive but they still need that wing to help push the rear wheels into the ground and improve cornering speed.

    If wings were just for traction you would not need the front wing on a F1 car ... :)

    Pete
     
  20. senna21

    senna21 F1 Rookie

    Jul 2, 2004
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    Great Flat Bottom Pics: :)

    http://www.mulsannescorner.com/benzCLR1.html

    Wings are there for increasing cornering speed not traction for acceleration. The faster you can get through a corner the higher you can gear your car for the straights. Or reach terminal velocity on the straights. The more time you spend at higher speed the faster your lap times will be. But, sometimes a bit slower cornering speed is needed in order to get better acceleration out of the turn. Don't forget cars accelerate quickest in a straight line.
     
  21. Ferrari0324

    Ferrari0324 F1 Rookie

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    Not always true. For the most part, ricers build cars that aren't capable of high enough speeds to require a wing, let alone one that can be used on an airplane. However, if you've ever heard of the Dodge SRT-4 (turbocharged neon) many people have removed their wings only to find that rear end is a little looser at higher speeds (this car is capable of 155 mph). So just b/c a car isn't rear wheel drive, the wing still helps to keep it on the ground.
     
  22. Korr

    Korr F1 World Champ
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    In many cases, that "wing" is actually a spoiler...it reduces the amount of lift generated by the air travelling over the car.
     
  23. smsmd

    smsmd Karting

    Nov 12, 2003
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    We may be saying something similar from a different point of reference. I was looking at Bernoulli's law in the more general sense. The pressure above and below the car is related to the speed of the airflow. I agree with you that the shape of a car is somewhat wing-like and that the flow over the car produces lift. I was looking at it from the other way, that to decrease the effects of this lift, you can speed up the molecules of air under the car, such that they are moving faster than those above. The intentional production of vortices under the car is an approach used by F1 to produce large amounts of negative pressure under the car. Essentially, they produce small tornados of air rotating at high speed under the car and just like in some atmospheric vortices (tornadoes, hurricanes, etc) the pressure at the "eye" becomes very low. I agree that there is drag associated with downforce production, whether by wings or aerodynamics.

    The air dams on the front not only divert air to brakes, etc, but diminish drag by diverting air from drag-producing underbodies, esp on those cars without panels to smooth airflow. When air is caught and dragged along on underbody parts, aerodynamic drag is high and airflow is slowed, making the difference in airspeed above and below the car that much more pronounced, producing even more net lift. The panels help eliminate this problem, as do the airdams.

    Thanks, steve
     
  24. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
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    Steve,

    I don't think we're that far off from one another. I agree that the flat bottom does promote a freer flow of air under the car. Although I'm not an engineer, I've always been facinated by the development of car designs, especially the evolution that wind tunnel testing and computer design have brought about in smoother body shapes and better management and use of airflow around, above and below the body.

    Regards,
    Steve
     
  25. Testacojones

    Testacojones F1 Veteran

    Nov 3, 2003
    5,139
    Terra



    The Bernoulli's principle you got it somewhat right but it needs to be explained the right way for some people to really understand it, as I helicopter pilot I know about the airfoil thing and you are right about that,

    Daniel Bernoulli stated that " as a fluid (in this case air) increases, its internal pressure decreases". To better understand this the best example is to visualize a venturi tube, this tube is narrower at the middle than at the ends. As air enters the tube it is traveling at a given speed and pressure. When it enters the narrow portion, its velocity increases and its pressure decreases. As the air continues to the wider portion of the tube, both pressure and speed return to their original values. However it is not necesary for air to pass through an enclosed tube for the Bernoulli's Principle to apply. Any surface that alters airflow causes a venturi effect. Now it is easy to see how can this principle work when it comes to air ground effects under a car.
     

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