wing

[billabongrob]

ya…i am actually interested too…I like the way it attaches but I need to know if im switching to a crx first b4 ordering.

[Brian_Hunter]

nm

[Brian_Hunter]

@digitalHorizon

An FF car needs downforce as much as any FR car does. Most of the North American market grew up with domestics, as I myself did (my Dad had a Buick GN). Because of this, we are all stuck in a drag racing mindset, where power and traction matter, and little else does. The most common argument I hear is, “you don’t need downforce on the rear of a FWD car.” For drag racing, unless you are in the very high echelon of FF drag racers, this is 99% true. Downforce is still a good thing, but only slightly for stability purposes. The essence of aerodynamics is that there exists a tradeoff between lift and drag (“L/D”, lift-to-drag ratio). This means, that for more downforce you add, more drag is created proportional to the shape and profile of the wing/airfoil. Different shapes and configurations produce different L/Ds. It is very complicated and probably beyond the scope of the common automotive enthusiast, so I’ll leave that to personal research if you’re interested.

Because the USDM market is so geared towared drag racing, wings on FWD cars seem stupid or pointless to them. However, in road racing aerodynamics take a completely different form. A FF car has different dynamics than a MR or FR car on a track, and those differences must be “corrected” in order for an FF car to be competitive. Whereas in drag racing you’re trying to put all the weight (normal force) on the front tires for acceleration traction, would you want to have traction at only the front two corners when taking a turn under 1.5g braking from 180 km/h? Traction is needed front AND rear on a road race car, which is why there is a wing on this car and more downforce will be added for next season. Corrections with weight balance, suspension setup, and brake bias, as well as aerodynamic balance and tuning are used to balance the car so that the driver feels as little understeer as possible, since that phenomenon is inherent to FF cars. Tuning the DA chassis in particular has been difficult. I myself have only been a small part of this project for only a short time, and I have learned much about FF aerodynamic tuning from Patrick himself, and added it to my own knowledge of fluid mechanics and computational fluid dynamics to produce a sound 3D fluid flow model around the race car.

What it comes down to is, even though a car is FF, you want downforce on all 4 corners of the car so that you’re getting as much grip as possible in cornering. If you look to any serious or professional race team that uses an FF platform (RealTime racing RSX/TSX, any BTCC FF teams, Super Taikyu series japan) they all use large aerodynamic devices to plant the rear of the car to correct the front end normal force bias inherent to FWD cars.

Thanks for your interest.

Here is my problem with pretty much ANY spoiler on ANY street car. They are almost always attached to the hatch or trunk so how effective can they really be??? So wouldnt any spoiler mounted like this be purely cosmetic?? I mean its only ‘connected’ to the body through a rubber gasket and a relatively flimsy latch. I dont think its downforce would be effectively or consistently transmitted to the wheels through the trunk lid.

[system]

@Brian_Hunter

Here is my problem with pretty much ANY spoiler on ANY street car. They are almost always attached to the hatch or trunk so how effective can they really be??? So wouldnt any spoiler mounted like this be purely cosmetic?? I mean its only ‘connected’ to the body through a rubber gasket and a relatively flimsy latch. I dont think its downforce would be effectively or consistently transmitted to the wheels through the trunk lid.

I don’t understand your reasoning… how else are you supposed to attach a wing? Once again, are you saying that any trunk mounted spoiler wouldn’t be putting downforce on the rear of the car? In that case, why do all stock bodied racing series (even NASCAR, NHRA funny cars/pro stock, BTCC, JGTC, etc) ALL have wings attached to the trunk or body?

The answer lies in simple physics. The aerodynamics part is beyond reach of most common enthusiasts, so I’ll leave that to just say that a spoiler of ANY shape produces aerodynamic forces of some sort. Most produce at least a little bit of downforce, which we will call F. Now, if you take a free body diagram of the spoiler alone, without the car, floating in the free stream, its aerodynamic force would be pushing down and pulling back (downforce and drag, respectively). In order for Newton’s second law to be satisfied (force is equal to the time rate of change of the velocity, or F = ma), all of the forces must add to zero in order for the spoiler to not have a net acceleration in one direction, or a vector combination of two or 3 (a = axi + ayj + azk), where i, j, and k are the unit vectors in the three Cartesian axes. This means that, for the spoiler to not be flying through the trunk because of its downforce, the trunk must provide the normal force opposed to it. This is much the same as a heavy book being placed on a table. In order for the book to not fall to the ground, the table provides the normal force opposed to the weight of the book.

So, the force on the wing F is now part of the entire system, which includes the car body, spoiler, and all aerodynamic forces on it. The free body diagram of this system is quite complex, but we’ll simplify it to the vertical forces, that being aerodynamic downforce produced by its spoiler, lift created by the car body itself, and the weight (mg) of the system components, all summed up and acting at different locations relative to the overall CG of the system. The ground provides the normal force that opposes all the downforce forces so that the car doesn’t accelerate into the ground. Thus, if there is a vertical force on the wing, and the wing is part of the system, its opposing force will be at one of the points where the normal force is applied, that being the 4 wheels where the car contacts the ground.

As was stated, the actual system is much more complex than this, with progressive spring rates adding nonlinearities to the system due to its non-linear forces as displacement increases, as well as body deformation and aeroelastic phenomena.

I guess the simplest way I can describe it is, if you put your hand under 1 leg of a table, and added weights to the top of the table, would your hand feel it or not? That is the argument that you are bringing, that if you add downforce to a point that is not directly connected to the wheel/suspension, that downforce would not be felt or effective at the wheels.

Doing this experiment, do you think this is correct?

[system]

@tnd2gen

Having spent more time in Japan than in the US, It is apparent that Americans do not take advantage of aero tuning while so much of the tuning in Japan revolves around it. Of all the times I went to the track in Japan, its was hard to find any cars without the benefit of aero tuning.

Why take advantage of aero dynamics when pretty much all of the USDM muscle cars are as aerodynamically capable as a box with wheels?? just build the motor as big as possible, juice out as much hp as possible, and hoppe that the feeble wind cast down from mother nature will have no effect!!!

ok, i’m sorry, that was a cheap shot at domestic lovers…

edit: Riceeater, I wanna see more pics of the Camaro…Send me some to primogen2@hotmail.com please…:pupeyes:

[DB2-R81]

Those things tacked to the bottom of the rear bumper cover and the rear mud flaps add nifty cosmetic appeal but are about as aerodynamic as a parachute.

You can do more for this car aerodynamically then that wing ever will by spending 5 min. to get rid of them, there not ment for a race car, nor is an exhaust system that hangs in the air stream.

Seal the rear bumper cover and spend some time properly hanging the exhaust system if you need it for the street. Small things aerodynamically will certainly help that car to go faster!

[chsscott]

You should hack up your rear bumper to get rid of that bag of sand you’re dragging around at 110mph. Oh yeah, I’m selling my Wings West commando spoiler if you ever wanted to do testing with different spoilers.

[Brian_Hunter]

@digitalHorizon

I don’t understand your reasoning… how else are you supposed to attach a wing? Once again, are you saying that any trunk mounted spoiler wouldn’t be putting downforce on the rear of the car? In that case, why do all stock bodied racing series (even NASCAR, NHRA funny cars/pro stock, BTCC, JGTC, etc) ALL have wings attached to the trunk or body?

The answer lies in simple physics. The aerodynamics part is beyond reach of most common enthusiasts, so I’ll leave that to just say that a spoiler of ANY shape produces aerodynamic forces of some sort. Most produce at least a little bit of downforce, which we will call F. Now, if you take a free body diagram of the spoiler alone, without the car, floating in the free stream, its aerodynamic force would be pushing down and pulling back (downforce and drag, respectively). In order for Newton’s second law to be satisfied (force is equal to the time rate of change of the velocity, or F = ma), all of the forces must add to zero in order for the spoiler to not have a net acceleration in one direction, or a vector combination of two or 3 (a = axi + ayj + azk), where i, j, and k are the unit vectors in the three Cartesian axes. This means that, for the spoiler to not be flying through the trunk because of its downforce, the trunk must provide the normal force opposed to it. This is much the same as a heavy book being placed on a table. In order for the book to not fall to the ground, the table provides the normal force opposed to the weight of the book.

So, the force on the wing F is now part of the entire system, which includes the car body, spoiler, and all aerodynamic forces on it. The free body diagram of this system is quite complex, but we’ll simplify it to the vertical forces, that being aerodynamic downforce produced by its spoiler, lift created by the car body itself, and the weight (mg) of the system components, all summed up and acting at different locations relative to the overall CG of the system. The ground provides the normal force that opposes all the downforce forces so that the car doesn’t accelerate into the ground. Thus, if there is a vertical force on the wing, and the wing is part of the system, its opposing force will be at one of the points where the normal force is applied, that being the 4 wheels where the car contacts the ground.

As was stated, the actual system is much more complex than this, with progressive spring rates adding nonlinearities to the system due to its non-linear forces as displacement increases, as well as body deformation and aeroelastic phenomena.

I guess the simplest way I can describe it is, if you put your hand under 1 leg of a table, and added weights to the top of the table, would your hand feel it or not? That is the argument that you are bringing, that if you add downforce to a point that is not directly connected to the wheel/suspension, that downforce would not be felt or effective at the wheels.

Doing this experiment, do you think this is correct?

A street-driven car has flimsy body panels, especially when compared to a table.

Let’s do an experiment: punch a dining room table. You’ll break bones. Punch the trunklid of a Civic. You’ll leave a decent mark in it.

Take another look at how those spoilers are attached to a NASCAR vehicle and get back to me.

[system]

You’re right, NASCAR panels are so rigid they NEVER deform or flex.

You guys are all right, I have no idea what I’m talking about. Someday I’d like to go to school to learn as much about race car aerodynamics as you guys do. :jerkoff:

[chsscott]

brian - Go sit on your trunk and tell me if the suspension moves down at all. Does all your weight just get absorbed by the trunk lid? Do Honda engineers know how to get around Newton’s Laws?

[system]

Say DH, this may be a stupid question, but would a rear difuser (sp?) help that car in any way? I’m just curious as to what good they actually do (and remember, this is an idiot talking, so please leave it to as lamens a terms as possible).

[Brian_Hunter]

@chsscott

brian - Go sit on your trunk and tell me if the suspension moves down at all. Does all your weight just get absorbed by the trunk lid? Do Honda engineers know how to get around Newton’s Laws?

Yeah, but go out and wiggle on a trunk mounted spoiler. It will move ALOT. How can this effectively and consisntantly transmitted to the wheels when its not even stable??

@digitalHorizon

You’re right, NASCAR panels are so rigid they NEVER deform or flex.

You guys are all right, I have no idea what I’m talking about. Someday I’d like to go to school to learn as much about race car aerodynamics as you guys do. :jerkoff:

Look at a 1970 Superbird. That wing is connected directly through the frame through steel barstock in the trunk. It’s 3 feet tall so you can still open the trunk. (The NASCAR versions all ran 6" tall wings since you didn’t have to open the trunk.) Plus Nascar doesnt just use stock paneling, the rear of the car must be boxed in between the quarter panels and upper deck lid.

And DH, I havent gone to school for any of this stuff. So I dont know. I just know I can move a spoiler mounted to a deck lid or hatch around alot. And I dont see how with so much movment the downforce would be evenly and consistantly distributed to the rear wheels. I’m not claiming I know more than you about this, hell I know pretty much nothing about a car’s areodynamics, so there’s no need to be a fag about things.

[system]

@Brian_Hunter

And DH, I havent gone to school for any of this stuff. So I dont know. I just know I can move a spoiler mounted to a deck lid or hatch around alot. And I dont see how with so much movment the downforce would be evenly and consistantly distributed to the rear wheels. I’m not claiming I know more than you about this, hell I know pretty much nothing about a car’s areodynamics, so there’s no need to be a fag about things.

I hate to say it, but if you could move a spoiler around ALOT, it either

a) was put on shitty and half assed
b) was not a race ready stable spoiler, and some cheesy autozone shit
or c) all of the above

[Brian_Hunter]

@SleeperSedan

I hate to say it, but if you could move a spoiler around ALOT, it either

a) was put on shitty and half assed
b) was not a race ready stable spoiler, and some cheesy autozone shit
or c) all of the above

It’s bolted to a trunk lid connected to the unibody through two hinges (which move), a tiny latch (which bends and allows the trunk to move side-side)… and a rubber gasket which is not solid at all).

Push down on either side of the trunk. It flexes. That’s the point I’m trying to make.

Plus I dont even understand the point of adding down force the rear of a FF car in the first place. Yeah, it might give it a little more stability at very high speeds but our cars are notorious for understeering. Understeer means the car’s front wheels are not effective in making the car change direction. It means a tendancy to continue going straight despite a change in the steering wheel’s direction. Adding more downforce to the rear wheels of a FWD car will only make this worse, since there’s a bigger proportion of force on those rear wheels than the car was designed for, giving a definite weight bias to the rear wheels.

[system]

I don’t think it’s weight distribution that makes under/oversteering, it’s the drivetrain…FWD cars understeer because the wheels that are turning are aslo spinning, causing them to tend to straighten out pulling you to the outside of the turn…

A RWD car, teh wheels are just turning, so more emphasis gets placed on them and they tend to steer more being taht the car is being pushed from the back, not pulled form the front…

It has been stated time and time again why a FWD TRACK car needs downforce on the rear…In many threads…It doesn’t matter what you think, it’s what the laws of physics are…If you don’t understand it I’m sure Danny/DIgitalHorizon will gladly explain it…He always does…

Plus a wing isnt making enough downforce to lift the front end of a car with a 300 plus pound engine in the front…it makes just enough to keep the back planted under hard braking…

[Brian_Hunter]

I understand the laws of physics. It might help in certain situations like under hard braking or stabilizing you at very high speeds. But at the same time wouldnt it also hurt you in some situations?? Like anytime when your losing traction with your front wheels? Your spoiler is adding downforce to the rear wheels which is just making things worse.

The only way I see it not affecting the front wheels much is if it doesnt actually add that much downforce to the rear, in which case it would mean its pretty worthless.

[DB2-R81]

The problem is caused by the design shape of most production-based cars. The shape creates a mass of turbulent air that forms right behind the rearmost and highest point of the roofline on most cars. On a three door Integra this is right above the hatch glass area, and this turbulent air has a net effect of attempting to lift the rear of the car off the road at speed.

Fwd or the location of the drive wheels has virtually nothing to do with how a wing will affect a car. Fwd cars have a push/under steer nature by design. To reduce under steer on low speed corners; i.e. “get the car to handle” enthusiasts create a neutral to loose handling car with springs, anti sway bars, tires & alignment. This condition promotes rotation/over steer in low speed corners, “handling”. But this same low-speed rotation can get dangerous at high-speed where you want the stability of a slight push/under steer condition.

A rear wing is used to BALANCE the car in high-speed transitions and cornering. Yes, you could say in essence a rear wing promotes under steer or stability at speed to achieve a neutral or slight under steering car. In addition if you add a front splitter or front end down force into the equation then you need even more wing to balance the car at high speed.

[system]

Like I said before, I don’t think weight is the factor more than power is…

When a FWD car spins through first/second, it’s cause of power, not weight…Consider the fact that a RWD car would spin through its first two gears. Those cars have not nearly as much weight over the rear tires as a FWD car would…It becomes a factor of power, not weight distribution.

Like I said earlier, you have a FWD car with a 300+ pound engine sitting over it…Sure off the jump the weight shifts to the back and you lose traction, but once rolling the downforce on the rear is not strong enough to lift the fornt end up, only strong enough to keep the rear planted…

Aerodynamics is a very in depth topic, and I am sure I missed some things…

@Brian_Hunter

The only way I see it not affecting the front wheels much is if it doesnt actually add that much downforce to the rear, in which case it would mean its pretty worthless.

Not necessarily…You wouldn’t want to have such downforce it lifts the front, but you want enough to keep the back down when braking, being that the car shifts forward…

Trust me, if spoilers did not help FWD cars, they would not be on the race prepped track cars that are FWD…

sidenote: an Integra Type-R beat a Carrera Turbo in a track race (I forget the event name)…He had a huge spoiler for added downforce…:shrug:

[Preston]

@Brian_Hunter

Yeah, but go out and wiggle on a trunk mounted spoiler. It will move ALOT. How can this effectively and consisntantly transmitted to the wheels when its not even stable??

Brian, do you even know what kind of education background Daniel (DigitalHorizon) has? He is an Aerospace Engineer.

So I guess we are all supposed to listen to you and everyone here who THINKS they know what they are talking about, with no education in it, and not listen to the guy who does this for a living :roll: God, this fucking place is going downhill.

The only person other than Daniel and Pat that knows what his is talking about is Marc Sasso.

[Brian_Hunter]

@Preston

Brian, do you even know what kind of education background Daniel (DigitalHorizon) has? He is an Aerospace Engineer.

So I guess we are all supposed to listen to you and everyone here who THINKS they know what they are talking about, with no education in it, and not listen to the guy who does this for a living :roll: God, this fucking place is going downhill.

The only person other than Daniel and Pat that knows what his is talking about is Marc Sasso.

Whatever, at this point I’m done with this whole thread. Why have you guys acted like I’m trying to argue with DH?? I have stated from the begining I dont know anything about the subject and I wanted to learn. All the race cars I have ever seen have the spoiler mounted directly to the frame/tube chassis. I just didnt see how effective a spoiler could be when its mounted to something as flimsey as a trunk lid. I mean you wouldnt put rubber bushings between your strut bars and the body of the car, which is essentially what the rubber stripping around the hatch is. And I also wanted to know how by adding downforce to the rear of the car it doesnt adversly affect the front wheels traction while lets say, high speed cornering when lots of downforce is being applied to the rear and you need all the weight you can get on the front wheels. With more down force on the rear than on the front how can that not shift the weight and lessen traction??

It would of been nice to learn why all these points I brought up dont seem to matter at all. The only person who actually knows anything about the subject in this thread just acted like a ass and didnt clue me in on much. Only fact I disputed with him was how NASCAR spoilers are attached, and thats the last I heard from him. Everyone who replied to me was oh so quick to tell me I didnt know shit, but no one actually told me WHY I was wrong. To me these are all valid points and I wanted to know why none of them seem to matter. But like I said, I really dont give a fuck about any of this anymore. :surrend: