Ludikraut

iTrader: (17)

Take a look at the Ferrari Enzo underbody design. This is what every Evo should aspire to...



l8r)

redvolution

iTrader: (3)

Where can I buy seam tape? I want to cover the giant fender gaps in the front of the car...

tvbf1

iTrader: (1)

This idea is wrong, sorry but most of the car's down force can be found on underneath the car. Take F1 cars, it looks like the front and rear wing produce the most downforce, but it's not. Their purpose is mainly for stability and very minimal downforce.

Well if you're saying that's for open wheel car then I'll use the example of the Ferrari's. I'm sure you all know the Ferrari F-50. It has a big tail or wing in back, but the new Enzo does not. The reason is because Ferrari incorporated the F1 ideology into the their cars. With the great engineering of the underpanel, it eliminated the necessity of the wing in the rear. This started back with the F-355 they start to have underpannels.

tvbf1

iTrader: (1)

Rear Diffuser acts as an anit parachute because guides air. Well we know that the air flowing underneath your car will have upward woosh once it exit the underneath of your car. The air rushes back up in a circular motion will then grap onto the back of your car causing drag, or areo inefficient. Rear diffusers is to channel the air underneath your to stop this this from occuring. That's why they have the fins, it's to speed up the air the underneath so that the woosh will occur further away from the car which reduces drag.

Also air doesn't just doesn't move from front to back, but it moves from side to side as you turn. The fins are also design to channel the air flow to create stability around the turns. Not just that, the air also behaves differently under braking too.

trinydex

iTrader: (12)

what about the idea is wrong? think for a second. what happens when you keep air away from the underside of the car? what is downforce? what did i mean when i said keeping air away from the front of the car but letting it in the sides doesn't help. slow your roll.

also... wings are for stability and they're for downforce, those two are the same thing. increased grip is increased stability. they don't want to make the car aerodynamically stable in yaw, otherwise they wouldn't be able to turn and steering response would become crap. those videos you're undoubtedly referring to with those champ cars flipping upside down at the top of a crest are examples of losing grip and losing downforce stability.

wanna let me know how diffusers work? or shall i tell you that too?

trinydex

iTrader: (12)

this is not the reason that diffusers are an antiparachute. antiparachutes are indeed a way to guide air and so are diffusers but this whoosh that you talk about has nothing to do with the antiparachute effect. the antiparachute effect is what happens when you have a hollow bumper protruding into the underside of a production vehicle. this bumper then acts as an air brake of a parachute. sealing away this hollow area eliminates the effect. a diffuser is capable of this.

the woosh as you call it is called tail wind. the tail wind of a diffuser actually CAUSES drag and it has nothing to do with ejecting the tail wind further from the car so it doesn't 'grab' onto your trunk and hold on.

the reason the tail wind from a diffuser causes drag is because it curls axially. the ideal way to slip through a fluid is to have everything flow smoothly over the object. this of course is speed dependant. but for an optomised range something smooth will flow best. but this isn't the goal of f1 they make 600+ horsepower because they want to make downforce, so overcoming the drag associated with that is what the horsepower is for.

if you want to argue with me about that too then i'm gonna have someone delete all your posts in this thread.

Djazair

iTrader: (1)

Disclaimer: I don't claim to be an aero expert, but I do know a few things...

Downforce is created thru pressure differentials. The normal road car is like a standard airplane wing, longer chord length on top than bottom. The air going over the top has to move faster than the air underneath. This creates lower pressure above the car, and since pressure tends to move from high to low, this creates lift. Some cars, like the EVO are zero lift (no actual downforce). A VW New Beetle creates something like 600lbs of lift at 80mph! They've got that flip up wing now.

Limiting the amount of air under the car, as well as speeding it up, lowers the pressure under the car. Notice the tunnels on the Enzo pic, this makes the underside curved over the length. The strakes on a diffuser are for straightening the airflow b/c turbulence raises the pressure. Ride height is critical, the lower you can go the better for downforce. This is why almost every series has a minimum ride height requirement. Flat bottoms with skirts are also outlawed in most series b/c they make a big improvement. All of these tricks also make the car very pitch sensitive, the aero loading then depends highly on the pitch attitude of the car.

my 2 cents.

trinydex

iTrader: (12)

ok fine... you win the being nicer award.

tvbf1

iTrader: (1)

Wow deleting my thread, that's pretty serious. Well first of all I appologize if I offend some of you.

I don't mind that you guys point out my errors in thinking, actually I thank you for it because it just show me that I have more to learn. I'm not trying to argue, but it was my fault to say that trinydex you're wrong. I'm willing to learn from other and listen to what you have to say and I love aero so lets talk.

Djazair, you were mentioning about an airplan wing right? I took physics in College too so I know a little, little, about it. I idea of the airplane wing to create lift right. Like you said the distance on top of the wing is longer then the bottom which make the distance that the wind or air have to travel is longer in top then bottom which which causes a low pressure on the bottom inturns causes lift. Correct? That's why if you look at our EVO carbon fiber tail, it's like an upside down airplane wing right. Flater on top and curvier on the bottom. To generate downforce. Right?

trinydex, the reason why I said that they want airflow underneath your car is because of this. Think of a water hose, if you squeeze it, the pressure increase and the water will spray out stronger. Samething with air. Fluid dynamics and aero dynamics have similar characteristics. If you force air into a channelled area, it will move faster. So the air that's moving under the car is really fast because it's being squeezed from our air damp/front lip or how you would like to call it and the road. That's why exotic car like the ferrari's have superb underpanlled to utilizes the air flowing underneath to car to generate even more down force. The Enzo I believe generates almost 2,000 lbs of down force at 170 or 180 (for stability) and then reduces as it gets higher for top speed. So do to it's underpannel channelling of the wind/air it's able to generate such downforce and be aero efficient, thus eliminating the need of a rear wing like the F-50 because they said that it actually causes drag. I didn't make this stuff about the Enzo up, it in motor trend, car and drive, etc.....

I'm not here to argue, and I love aeros, so lets talk guys. I'm willing to learn from you.

trinydex

iTrader: (12)

fluid dynamics is aerodynamics. if you squeeze a hose the water comes out with more velocity and less pressure. faster means less pressure.

you want to evacuate the air from under the car. why does the enzo have fans under the bonnet? because those fans act to evacuate air from the bottom of the car effectively vacuuming the car to the ground. while that sounds rather proposterous and exagerated, that is in effect what is happening.

the perfect system is one in which all the air is taken out of the underside of the car. this creates a perfect vacuum and you are then making so much downforce that your chassis will scrape the ground. now in order to create this system the entire car has to be sealed off with regards to the ground. this is why i said it doesn't help to take away air from the front but let it slip in on the sides. becuase if you did then the pressure would be equalized and you're not making anything (you may make front downforce, but not full ground effects downforce)

also you talk about the wing shape. look at the side profile of a car and tell me what that looks like.

also, i wouldn't be one to disagree with ferrari. wings do create drag, the fact is that they have a finite cross sectional area while facing fluid flow. that means there will be some normal force drag. that does not mean that ground effects does not create drag. they create even more. would it be smart to use both and exacerbate the situation? absolutely not. but they do in formula don't they? because at that level it's not about drag it's about downforce. of course they don't want to make any unnecessary drag... but all the downforce is very necessary

nothere

iTrader: (23)

wasn't it ALFA ROMEO who won everything in the seventies with the underpants fans.

tvbf1

iTrader: (1)

trinydex you said that the air flowing underneath the car is unwanted, and I only wanted to prove my point that air flowing underneath your car is very important because you can extract a very large amount of down force. This is what you said, "mmm you definitely want to keep as much air away from underneath the car as possible. some rules don't allow you to but in a rules barred vehicle you could.

that said you'd have to keep hte air out of ALL of the vehicle. keeping air out in front and letting it come in the sides isn't that helpful."

You said that you want to keep as much air away from underneath as possible, but you know what, F1, Ferrari, and the Lexus spends more time studing the air flow underneath the car then anywhere else. In F1 and the exotic cars, most of the down force is generated from the underpannels. The Lexus is so quited because Toyota studies the air flow underneath the car. They found that most of the noise comes from underneath the car and it could reduce by using aerodynamics. That's what I wanted to prove to you.

About the Evo rear wing, I was talking about the carbon fiber part like I said in my thread.

I don't know what you have against me, but I appologized for bluntly said you are wrong which you ARE. trinydex you're the one that didn't accept my appology in the first and then you criticize me for trying to have a conversation about aerodynamics with everyone else. If you want to delete my thread, go ahead. Actually please delete them, I don't want people to know that discussed aerodynamics with a Mike Gascoyne, or Adriane Newey WANNA BE. Thinking you're right and everyone else is wrong, please

trinydex

iTrader: (12)

dude... seriously... you just don't happen to know enough to know that you're wrong.

even within the things that you pointed out. i was referring to rules barred car in my original post that you antagonized. WOW. relevant!

if there is no air under a car... there is no noise! wow see how what i cited as being best would in fact be best?

f1 cars aren't allowed to use ground effects and active aerodynamics such as fans and moving spoilers. they're also open wheeled cars which means you can only seal off the center portion of the vehicle which they did before it was banned.

i already know that much of the downforce is generated by underpanels... why do you think i was talkin' about underbody diffusing? but the FACT is that the underbody work is crucial there because there IS air flow. if there were a vacuum there or if you could keep enough air out of the under area of the car there would be no such need.

because that is indeed impossible (which you didn't even cite btw) because the car would be scraping on the ground and then REALLY scraping on the ground once you started moving faster and generating more downforce... the diffusing and other contours are necessary.

answer me this and this will learn you quite a bit. WHAT DO YOU MEAN BY MOST OF THE DOWNFORCE CAN BE FOUND UNDERNEATH THE CAR??? it's not found in the AIR THERE (it's found in the lack of air there, less air density is less air pressure)... think about it... think about atmosphereic pressure... think about water and how as you go further down the force increases... think of us at the bottom of a sea of air... think about pressure differentials and how 0 air pressure is less than atmospheric and how they use THOSE aspects of fluid dynamics to create downforce.

trinydex

iTrader: (12)

and you know what... you went and turned this into a ****ty thread when it was going really well.

i'm sure more than one person on evom will tell you that i'm the first person to ask questions and learn from toher people that i know know more than me. but if you're gonna come and accuse me of being wrong... at least show some mastery of the subject matter. i mean the stuff you're saying it's just... you're totally playing the wrong ballgame.

x838nwy

Think so. I also seem to recall that Bernie Ecclestone was actually their team principle at the time. I think they were trying to make a sort of reverse helicopter effect. Instead of synthesising downforce, they tried to acutally suck the car to the road literally. I mean if you can have propellors pushing you to the ground, who gives a rats **** if your undercar air flow is a little off?

Anyway, going back to the underbody airflow, one team -WIlliams/Lotus? in the late 70's ran their cars with ground rubbing (it actually supported itself on the road) sideskirts. This prevented the air entering from the sides and as a result, they were miles ahead of everybody. The skirt was banned the following year.

Underbody airflow is governed in F1 cars mainly by the minimum height. There's a plank of wood under the car which is must be of a certain height from the ground and at the same level as the lowest point in the car. The piece of wood cannot wear by more than 1mm after a race. This is to control the minimum height during the race which therefore IMO means that getting closer to the ground gives you more downforce and so it would appear the having less air under the car is a good thing. If not, they would all be trying to get air under the car deliberately by designing keels and barge boards that actually scoop them under the car and the minimum floor height would not be an issue.

The concept, however seems to be that there is much downforce to be had by paying attention to the under floor of the car - I think everybody got that.