Aerodynamics Question

[RoyVegasPinoy]

If a spoiler creates down force to keep the car on the ground, will an up force reduce the weight of the car as it creates lift?

I got stuck in traffic today and I had time to complain and wish that my car had wings... haha

[RoyVegasPinoy]

Where are the smart people!

[blackbelt]

Yes and no, It will cause you to loose traction and it will cause the weight of the car on the road to lower while at speed.

[MOOGEN]

well according to newton's second law: for every force there's an equal and opposite force.

F=ma
m-your car plus you
a- gravity (if you are not moving) (y component)
- if your moving then you will now have forward motion(x component)

You wanted to know if up-force will reduce your weight... the answer is No and yes. Depending on where you are looking... we usually draw free body diagrams for this kinda thing.

Looking at the ground:

Yes there will be a slight reduction of weight off the floor(considering your car has equal uplift on front and rear) but if you took away the floor you will notice that the uplift wind is now supporting a portion of your weight. This uplift wind can be considered as drag friction coefficient.

equation mcar = (+ywind) + (+yfloor)

where as if your just sitting then ywind=0 , m=+yfloor or static(meaning stable and non moving),

0= -m + yfloor + 0

you get it? So in the end it pretty much means that your car will not reduce any weight unless there is physical change, a change in gravity, or external force.


Someone correct me if i'm wrong.

[MOOGEN]

to sum a little more... Your weight will always be distributed amongst the wind and the floor and adding the two will yield your total weight which is you and your car. so.... NO

[BobSassafrass]

zooom
http://www.mobilewhack.com/reviews/flybyq3.gif

[RoyVegasPinoy]

Looking at the ground:

Yes there will be a slight reduction of weight off the floor(considering your car has equal uplift on front and rear) but if you took away the floor you will notice that the uplift wind is now supporting a portion of your weight. This uplift wind can be considered as drag friction coefficient.

I've already given in to agreeing with your explanation, but for the sake of my lack of knowledge in physics, I'm going to ask some questions about this.

So you said that with a lifting force, you now have to support your weight as its counterforce. But weight is still a factor without the force of lift, so I am thinking that lift would only subtract weight.

I understand how lift can be considered as drag though, but I'm just thinking that with enough speed to provide airflow for lift, a car can run lighter.

Once again, I'm probably missing a few key points in here so excuse my lack of knowledge.

[PAPITUYO326]

Mech & Aero Engineering dork here.:mangel:

Wings do not reduce weight, they simply create a force that counteracts it (LIFT). A spoiler is just an upwide down wing, which in turn creates negative lift, aka downforce. The force of a spoiler acts parallel to the weight of the object.

How do wings work:
-Wings cause the fluid flowing over the top of them to accelerate. This is due to the curved upper surface of the wing.

-Using Bernoulis law, we can find the relation

Pb + 1/2pvt²=Pt+1/2pvt²

where P is pressure and V is velocity (b for bottom, t for top). Thus since the velocity is faster on top, it must exhibit lower pressure.

-The pressure disparity is then summed throughout all points on the wing. Pressure = F/Area. Multiply the Pressure by the normal area, and you get the upward force created by the wing, aka LIFT.


Wings also create more drag as they create more lift. Thus, there is a point of maximum efficiency for each wing. Also, traveling at too high of a velocity will cause viscous forces to dominate and induce separation, which creates a pocket of slow moving air on top of the wing, but below the fast moving air. This slow moving air no longer exhibits low pressure, and can cause lift to cease (Stall).


You could definitely model a wing to lift up a car. Very easy to do on a lightweight vehicle. The problem is that after you create the lift, you don't have the wheels touching anything, which could make speeding up a while flying a bit troublesome to say the least hehe.

[MugsyTheGr8]

Mech & Aero Engineering dork here.:mangel:

Wings do not reduce weight, they simply create a force that counteracts it (LIFT). A spoiler is just an upwide down wing, which in turn creates negative lift, aka downforce. The force of a spoiler acts parallel to the weight of the object.

How do wings work:
-Wings cause the fluid flowing over the top of them to accelerate. This is due to the curved upper surface of the wing.

-Using Bernoulis law, we can find the relation

Pb + 1/2pvt²=Pt+1/2pvt²

where P is pressure and V is velocity (b for bottom, t for top). Thus since the velocity is faster on top, it must exhibit lower pressure.

-The pressure disparity is then summed throughout all points on the wing. Pressure = F/Area. Multiply the Pressure by the normal area, and you get the upward force created by the wing, aka LIFT.


Wings also create more drag as they create more lift. Thus, there is a point of maximum efficiency for each wing. Also, traveling at too high of a velocity will cause viscous forces to dominate and induce separation, which creates a pocket of slow moving air on top of the wing, but below the fast moving air. This slow moving air no longer exhibits low pressure, and can cause lift to cease (Stall).


You could definitely model a wing to lift up a car. Very easy to do on a lightweight vehicle. The problem is that after you create the lift, you don't have the wheels touching anything, which could make speeding up a while flying a bit troublesome to say the least hehe.

:thumb: good stuff, i wish you taught my physics class.

[Karma]

Mech & Aero Engineering dork here.:mangel:

Wings do not reduce weight, they simply create a force that counteracts it (LIFT). A spoiler is just an upwide down wing, which in turn creates negative lift, aka downforce. The force of a spoiler acts parallel to the weight of the object.

How do wings work:
-Wings cause the fluid flowing over the top of them to accelerate. This is due to the curved upper surface of the wing.

:clap2: bingo. main points right there.

Aeronautics major (pilot) :mangel:

[RedSiBaron]

Mech & Aero Engineering dork here.:mangel:

Wings do not reduce weight, they simply create a force that counteracts it (LIFT). A spoiler is just an upwide down wing, which in turn creates negative lift, aka downforce. The force of a spoiler acts parallel to the weight of the object.

How do wings work:
-Wings cause the fluid flowing over the top of them to accelerate. This is due to the curved upper surface of the wing.

-Using Bernoulis law, we can find the relation

Pb + 1/2pvt²=Pt+1/2pvt²

where P is pressure and V is velocity (b for bottom, t for top). Thus since the velocity is faster on top, it must exhibit lower pressure.

-The pressure disparity is then summed throughout all points on the wing. Pressure = F/Area. Multiply the Pressure by the normal area, and you get the upward force created by the wing, aka LIFT.


Wings also create more drag as they create more lift. Thus, there is a point of maximum efficiency for each wing. Also, traveling at too high of a velocity will cause viscous forces to dominate and induce separation, which creates a pocket of slow moving air on top of the wing, but below the fast moving air. This slow moving air no longer exhibits low pressure, and can cause lift to cease (Stall).


You could definitely model a wing to lift up a car. Very easy to do on a lightweight vehicle. The problem is that after you create the lift, you don't have the wheels touching anything, which could make speeding up a while flying a bit troublesome to say the least hehe.

could not have put it better, and i used to be an aerospace engineer...

with a car you want a happy balance of downforce and less drag, you dont want lift...but this is pointless on a streetcar...with a streetcar all you need is an aerodynamicly "quiet" car with a low drag co-efficient...thats it, you dont need downforce...thats not to say certain street cars dont get some sort of this at certain speeds, im sure even our car has a little bit over 100mph just to help stabalize the car...i know my 86si had some aero effects in the floorpan, and at 90mph the car went quiet and squatted down to the ground a little...as crazy as that seems

[PuMpKiN_Ep3]

jejejejjeje... lol..... seems like you have a lot of time to think,,,,

[jimmyjames]

Spoilers do not create downforce as people think.
Wings on the back do. (those ricer ones with the exposed bolts and crap.)

Spoilers "spoil" the laminar flow of the air stream coming over the top of the car and down the back thus reducing the drag of the air following the entire surface of the car.
This is why spoilers on regular cars are justified. Because they will somewhat improve their gas mileage and handling at highway speeds by reducing the drag on the rear part of the car. It is more noticeable on cars with steep rear windows. The spoiler on a sedan or coupe will kind of make it perform closer to a hatch type body (the higher the spoiler) but also prevent a large area of negative pressure that is common with flat rear vehicles (hatches, vans, SUVs)

In these pictures, you can see how the air follows the whole length of the car; up and the down the back glass and trunk area. Every linear inch of which creates an amount of drag. The closer the airstream can get horizontal or the shorter the overall distance, the less overall drag.
http://us1.webpublications.com.au/static/images/articles/i1086/108676_5lo.jpg
http://www.tridenthonda.co.uk/images/honda_accord_wind_tunnel_rounded_left_shadow.jpg

Here is a typical hatch air flow (spoilers don't do much). However, you can see clearly that the airstream doesn't have to follow the rear of the car back down. In cases of hatchback, friction doesn't cause drag, the negative pressure in the back of the hatch will create it.
http://us1.webpublications.com.au/static/images/articles/i1086/108676_6lo.jpg

Another hatch. Notice the sloped back roof though. Unlike the Mercedes hatch above, the airstream is not left trying to figure out where to go after it leaves the roof. The slope helps shape the air back into how it was before the car entered that space. This shows how having an aerodynamic front AND rear section allows for good aerodynamics.
http://www.audiworld.com/news/99/wind/header.jpg

I am looking for a better pic but you can see here how the spoiler works to raise the airstream up off the rear of the car's surface to prevent contact/friction/drag. The area under the smoke would be essentially negative pressure here. The airstream is thus able to flow better up and over the car but the overall amount of drag due to friction and negative pressure is reduced.
http://user.chollian.net/~sa12/stirearflow.jpg

Here you can see the effect of downforce from a wing. (notice the airstream bounce off the wing instead of wing slicing slice through it because of its angle of attack to purposely produce downforce)
http://www.corvetteracebodies.com/wind%20tunnel%202-06%2018.jpg

More pics of a wing used to produce downforce.
http://www.webwombat.com.au/motoring/news_reports/images/1augaud3.JPG
http://www.totalmotorsport.com/Features/Cars/Storage/Audi-R10-WindTunnel-2006.jpg

Here is the best of both worlds. A spoiler designed with a certain angle of attack to produce mild downforce but also raise the airflow off the rear surface of the car to reduce drag.
http://www.cecwheels.com/images/medialibrary/windtunnel1.jpg

Here are 2 pictures of an NSX's spoiler in action. Notice how the air goes over the top of the car but does not follow the rear windshield back down but rather goes straight off over the spoiler...
http://world.honda.com/NSX/technology/image/t3_01.jpg
http://www.free-desktop-wallpaper-download.com/data/media/3/car_24.jpg

Everything Dave posted is accurate though too.
(former aerospace eng. major here)

[27rocks]

Finaly a bad ass thread....good stuff guys :hug:

[Trimix]

Really interesting thread. So a hatch body type is generally more aerodynamic than a normal sedan (without a spoiler)?

[jimmyjames]

Really interesting thread. So a hatch body type is generally more aerodynamic than a normal sedan (without a spoiler)?

Not entirely, there is a lot going on you DON'T see. On a hatch,the airstream goes straight back after the car but that leaves a large area of negative pressure where the car's space just occupied a moment before. Essentially, a hatch or any flat rear vehicle creates this suction behind it causing drag as well.
To overcome this, the makers of the EP created a slightly sloping rear glass as well as making the SIDES of the back portion of the car curvilinear (egg-shaped in plan view) so that the airstream AROUND the vehicle could come back and occupy that space in the rear faster. The Honda insight's rear half design is a perfect example of how a hatch can own all, FTW.
http://www.insightcentral.net/_images/prius-insight-side.jpg

It was not my intention to imply hatches are the most aerodynamic but rather show how a spoiler breaks up the laminar flow of the airstream reducing drag caused solely by friction between the air and back half of the car. A similar principle is employed in the JRSC intake runner design. Rather than provide good aerodynamic principle to optimize air flow, they create a system where turbulent flow allows for better movement of the air. (Turbulent flow reduces the friction and brute force provides the movement)
I am no expert on that stuff but perhaps Dave can shed some light on it.

See this pic. Even though the airstream goes around the surface, the angles involved prevent the air from conforming to the backside. The air goes back straight like the hatch does but you can clearly see the turbulent flow and eddy currents occurring in back of the object.
http://tennisclub.gsfc.nasa.gov/images/Tennis_Nospin_0700.jpg

[Trimix]

Aerodynamically wise, is there a big difference between a stock EP and one that has the HFP rear hatch spoiler?

[v1c10us]

Well, what about vortex generators, typically placed at the highest point on the roof line. (those little shark fins that span the width of the roof)
Do those do anything? They seem like they would do a very good job.


Also, downforce or upforce as you mentioned will be applied to one part of the car, the car is going to rotate on an invisible axis. As someone mentioned, the wind is being acted upon instead of the ground, this is the same reason if you put one of those little helicopters on a scale and fly it above the scale, the reading on the scale wont change.
So by lifting one end of the car, presumably the rear with an upside down wing, you would be transferring all of the weight to the front of the car.

[v1c10us]

since the air follows the shape of the car, gradually tapering the rear end will reduce drag.
Thats why the insight has that shape.
Although there is a level when it is no longer efficient to taper the rear of the car, this is called a Kammback.
The insight has a distinct kammback, as well as other cars such as the prius.
our car has a slight kammback, but not very distinct.
In cars with a very noticeable kammback adding a rear deck spoiler like the HFP would make more drag..

Although keep in mind, the underneath of the car is where the most drag is created. If you really wanted to get rid of drag, a fiberglass plate could cover the entire bottom of the car.

[Karma]

Well, what about vortex generators, typically placed at the highest point on the roof line. (those little shark fins that span the width of the roof)
Do those do anything? They seem like they would do a very good job.


those vortex generators (like those on the older evo) create turbulent flow to keep the airflow as close as possible to the surface. in other words, it's disrupting airflow purposely to reduce negative pressure.

jimmyjames, your examples are excellent. the tennis ball and golf ball are perfect examples of turbulent and laminar air flow.

look at the pingpong ball; it's smaller, lighter and smoother, but will not travel as far or as fast as the golf ball and tennis ball. the pingpong ball doesnt have any fuzz or dimples to cause early airflow separation. since the tennis ball and golf ball do, the airflow separates early, and then rushes back to fill in the negative area.

[RoyVegasPinoy]

You could definitely model a wing to lift up a car. Very easy to do on a lightweight vehicle. The problem is that after you create the lift, you don't have the wheels touching anything, which could make speeding up a while flying a bit troublesome to say the least hehe.

That would be awesome. But you know, it can be an adjustable wing to compensate for the speed so that it stays grounded. That would probably make for a great fuel efficient vehicle.

[RoyVegasPinoy]

So what I learned here is that ricers have more down force than us, haha.

But seriously. So with lift, comes drag. But if our wheels remain grounded, then we still have our thrust to compensate for the drag. So maybe flying is out of the option without a propeller, but it sounds like it's still possible to get a car to run "lightly" with proper wing placements.

[jimmyjames]

So maybe flying is out of the option without a propeller, but it sounds like it's still possible to get a car to run "lightly" with proper wing placements.In theory, it could happen but you would need a wing with the correct cross-section. It would need to be an airfoil design or else it would not create lift. If you placed a wing angled up, it may create upforce but it would be at the expense of increased drag and reduced speed.


jimmyjames, your examples are excellent. the tennis ball and golf ball are perfect examples of turbulent and laminar air flow.Thanks, we both learned it from the same source so no surprise you think so. :mwink:

[Karma]

Thanks, we both learned it from the same source so no surprise you think so. :mwink:

no surprise at all.

kinda wish i took up AE instead :mconfused:

[RoyVegasPinoy]

I'm still reading all the posts on here.. lots of info

[jimmyjames]

no surprise at all.

kinda wish i took up AE instead :mconfused:After the second year of tons of physics, calculus 6 or whatever and Statics class with Dr. Tej Gupta, you may change your mind. Riddle was great and being a rocket scientist had its appeal but I am a much happier architect.

[PAPITUYO326]

My dog jimmyjames dropping more knowledge. Ep Solo too.:mbiggrin: AEs unite!

Im actually interning this year with a Rocket Design firm. Rocket Scientists FTW.

[RedSiBaron]

After the second year of tons of physics, calculus 6 or whatever and Statics class with Dr. Tej Gupta, you may change your mind. Riddle was great and being a rocket scientist had its appeal but I am a much happier architect.

uhhh...we had a Dr. Gupta at Cincinnati...haha aerospace indians ftw...haha...

thats one thing i miss about being in aerospace is saying i was a rocket scientist, but being a car designer is just as awesome...i find it funny how we both went from engineering to a form of design!

[Trimix]

I'm guessing aerodynamics is improved with our steeply raked front windshield?

[JCEM]

In theory, it could happen but you would need a wing with the correct cross-section. It would need to be an airfoil design or else it would not create lift. If you placed a wing angled up, it may create upforce but it would be at the expense of increased drag and reduced speed.

Thanks, we both learned it from the same source so no surprise you think so. :mwink:

Is a car by nature not an airfoil design succeptible to lift if the correct velocity and an abnormal force is applied? I mean, you would occasionally see old open-wheel race cars lift off the ground and crash in spectacular fashion 20 years ago after say, hitting the edge of the track or clipping another car.

[MOOGEN]

Well, what about vortex generators, typically placed at the highest point on the roof line. (those little shark fins that span the width of the roof)
Do those do anything? They seem like they would do a very good job.


Also, downforce or upforce as you mentioned will be applied to one part of the car, the car is going to rotate on an invisible axis. As someone mentioned, the wind is being acted upon instead of the ground, this is the same reason if you put one of those little helicopters on a scale and fly it above the scale, the reading on the scale wont change.
So by lifting one end of the car, presumably the rear with an upside down wing, you would be transferring all of the weight to the front of the car.


that's correct... this is why in order for a car to keep force balance you must also compensate for the front and have an aerodynamically design front end. In my first post I mentioned "considering your car has equal uplift on front and rear" specifically for this example. This is why mugen products go hand in hand. The front lip and grill inserts help adjust downforce as well as the rear wing. But in your case you must creat an equilibrium and have the front create an equal uplift balancing with the rear wing. Its kinda cool how this works... kinda confusing at first but when you understand it, Physics is the only thing that makes sense in the world. LOL.

[siver-SI]

Ok this is simple for front wheel drive.

To put it simple

If you have a wing that has lift it will take weight off your rear tires but add weight to your front tires that makes your car have a more loose feeling. (your rear end wants to come around)

If you have a wing with a lot of down force it will put more weight on your rear tires and take it off your front tires causing your car to feel more tight. (your front end does not want to turn)

[v1c10us]

that's correct... this is why in order for a car to keep force balance you must also compensate for the front and have an aerodynamically design front end. In my first post I mentioned "considering your car has equal uplift on front and rear" specifically for this example. This is why mugen products go hand in hand. The front lip and grill inserts help adjust downforce as well as the rear wing. But in your case you must creat an equilibrium and have the front create an equal uplift balancing with the rear wing. Its kinda cool how this works... kinda confusing at first but when you understand it, Physics is the only thing that makes sense in the world. LOL.

Its sort of a completely pointless topic.
You may be able to generate uplift, but since all of our forward motion comes from the wheels, all you will ever do is make your car handle worse, and never go any faster.

The car would be slowly lifted as you built speed, then you'd be so light eventually that your car would float all over, handle like dunk because your camber would be all wonky, you'd be lifted off the ground a little bit by the weight reduction, increasing the undercar area making you less aerodynamic and you'd fall back to the ground untill you got stick in a middle part where you were un-aerodynamic but still handled cruddy, so you'd be slow.
If you could somehow surpass this, you would speed up, the car would get higher, but you'd get worse and worse traction untill you couldnt maintain speed and you would probably find the maximum speed you could maintain would be lower than it would without the weight reduction of the aerostuff.

not to mention in the event you ever changed the angle off the car you could end up flipping, or losing all traction on one side and spinning in a circle at high speeds.

[RoyVegasPinoy]

You guys are all so negative and thinking of ways why it wouldn't work!

Properly placed adjustable airfoils like that of a constant-speed propeller on an airplane would keep the lift/weight balanced and the tires grounded.

Maybe even a small vertical stabilizer/rudder to control rolls.

(By the way, obviously this is not something that I'm going to start building in my garage. It's just a thread I posted to think creatively.)

[v1c10us]

You guys are all so negative and thinking of ways why it wouldn't work!

Properly placed adjustable airfoils like that of a constant-speed propeller on an airplane would keep the lift/weight balanced and the tires grounded.

Maybe even a small vertical stabilizer/rudder to control rolls

(By the way, obviously this is not something that I'm going to start building in my garage. It's just a thread I posted to think creatively.)

right, so that would be great if we used rockets or propellers or jet engines for our propulsion.
But we use our wheels.
So theres a certain point of maximum efficiency which will undoubtedly be lower than our cars are now, at least for top speed.

The lift will also make for horible handling characteristics.
Pretend you are traveling at 60 miles an hour and you've managed to produce a 10 percent reduction of weight on all four courners.

when you change the angle of the car the lift characteristics combined with the force of the air hitting the car could drastically and instantly change your weight reduction to +20 or even 30 percent on one side and -20 to 30 on the other.
Factor in the body roll you're already encountering and the fact that you are trying to drive a car thats handling characteristic has suddenly changed so drastically that you have no idea what is going on and your losing traction as it is, and now you have even less traction because your car is lighter.
Its a hot mess.
A light car with downforce will handle better than a heavy car putting weight on the air.

[RoyVegasPinoy]

right, so that would be great if we used rockets or propellers or jet engines for our propulsion.
But we use our wheels.
So theres a certain point of maximum efficiency which will undoubtedly be lower than our cars are now, at least for top speed.

The lift will also make for horible handling characteristics.
Pretend you are traveling at 60 miles an hour and you've managed to produce a 10 percent reduction of weight on all four courners.

when you change the angle of the car the lift characteristics combined with the force of the air hitting the car could drastically and instantly change your weight reduction to +20 or even 30 percent on one side and -20 to 30 on the other.
Factor in the body roll you're already encountering and the fact that you are trying to drive a car thats handling characteristic has suddenly changed so drastically that you have no idea what is going on and your losing traction as it is, and now you have even less traction because your car is lighter.
Its a hot mess.
A light car with downforce will handle better than a heavy car putting weight on the air.

Well then, we have the issue of uneven lift when making turns. How about the use of synchronized left and right ailerons and rudder when turning the steering wheel? :msmile:

And who says the spoilers have to be set to "lift" when making turns? The adjustable airfoil can be set back to a down force in case of turns. But long straightaways and highways would probably save a lot of gas.

[v1c10us]

Well then, we have the issue of uneven lift when making turns. How about the use of synchronized left and right ailerons and rudder when turning the steering wheel? :msmile:

And who says the spoilers have to be set to "lift" when making turns? The adjustable airfoil can be set back to a down force in case of turns. But long straightaways and highways would probably save a lot of gas.

alright so you could do that, but would you want your car to be lifting off the ground when traction is your main concern?
An airfoil in nature would need to be flipped to change from lift to downforce.
On the highway, what happens if you change lanes quickly.
for a straightaway, yes thats great, but no highways are perfectly straight, nose dive from braking would have to be taken into account as well.
Its possible, but the amount of weight you'd have to add to make it work as well as extra stuff would probably make the car less aerodynamic, and would be more trouble than its worth.
You'd be better off just making all of those extra fins and shit into solar panels, or taking the weight that you'd put on and just making a fuel cell system.
There are much better ways to make an in efficient vehicle efficient than lift.
just plain old aerodynamics, under spoilers and below car air management would improve gas mileage more than weight reduction.

[RoyVegasPinoy]

But they promised us flying cars damnit!

[v1c10us]

give Moller a call and ask him about his skycar.

[Soviet]

If a spoiler creates down force to keep the car on the ground, will an up force reduce the weight of the car as it creates lift?

I got stuck in traffic today and I had time to complain and wish that my car had wings... haha


Additional lift = additional drag, which will suck for mpg.

[20CiviC02Si]

Those are some awesome pics!

[Trimix]

Does anybody know the drag coeff for our cars (stock)?

[v1c10us]

Does anybody know the drag coeff for our cars (stock)?

0.30 completely stock.
atleast on the sedan
i donno about the hatch

keep in mind the honda insight is incredibly aerodynamic and its cD is 0.25
so i cant imagine ours being any lower than .28

[Trimix]

I"m guessing the steeply-raked windshield on our EPs help too.

[MOOGEN]

^^ where'd you get those number? I'm just curious.

[v1c10us]

I"m guessing the steeply-raked windshield on our EPs help too.
our windshields are hardly steeply-raked..
They dont even classify as acutely angled.
But sure, they help
http://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Twike.jpg/800px-Twike.jpg
thats a steeply raked windshield, and also the most aerodynamic production car ever produced.
Half the cD of the insight.

[v1c10us]

^^ where'd you get those number? I'm just curious.

http://honda.jbcarpages.com/Civic/2004/index4.php
http://insightcentral.net/encyclopedia/enaero.html

[MOOGEN]

http://honda.jbcarpages.com/Civic/2004/index4.php
http://insightcentral.net/encyclopedia/enaero.html

thanks! very informational... and yeah I agree that this post is pretty much useless but it is very informational on how to keep your car on the ground at fast speed.

[SyckSiR]

Mech & Aero Engineering dork here.:mangel:

Wings do not reduce weight, they simply create a force that counteracts it (LIFT). A spoiler is just an upwide down wing, which in turn creates negative lift, aka downforce. The force of a spoiler acts parallel to the weight of the object.

How do wings work:
-Wings cause the fluid flowing over the top of them to accelerate. This is due to the curved upper surface of the wing.

-Using Bernoulis law, we can find the relation

Pb + 1/2pvt²=Pt+1/2pvt²

where P is pressure and V is velocity (b for bottom, t for top). Thus since the velocity is faster on top, it must exhibit lower pressure.

-The pressure disparity is then summed throughout all points on the wing. Pressure = F/Area. Multiply the Pressure by the normal area, and you get the upward force created by the wing, aka LIFT.


Wings also create more drag as they create more lift. Thus, there is a point of maximum efficiency for each wing. Also, traveling at too high of a velocity will cause viscous forces to dominate and induce separation, which creates a pocket of slow moving air on top of the wing, but below the fast moving air. This slow moving air no longer exhibits low pressure, and can cause lift to cease (Stall).


You could definitely model a wing to lift up a car. Very easy to do on a lightweight vehicle. The problem is that after you create the lift, you don't have the wheels touching anything, which could make speeding up a while flying a bit troublesome to say the least hehe.

mmm, some apc rocket tails should work to propel you once the wheels are off the ground! :caked:

[civictype_r04]

If a spoiler creates down force to keep the car on the ground, will an up force reduce the weight of the car as it creates lift?

I got stuck in traffic today and I had time to complain and wish that my car had wings... haha

WOW:der:

[2004ep3hatch]

moved to proper sub forum. :mbiggrin:

[RoyVegasPinoy]

WOW:der:
Hey, just thinking outside the box.


moved to proper sub forum. :mbiggrin:
Ya that's where I first posted it but someone had moved it to EP Discussion!

[MOOGEN]

LOL thats why I was like HUH? first it got moved to ep discuss then back to interior exterior. whatever gets the message out there. :mtongue: