| brcewane | 04-26-2005 01:04 PM |
EVO MR "Vortex Generator" on a WRX
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Hey guys,
I'm thinking of making my own "Vortex Generator" for the WRX out of fiberglass that would be like the EVO one seen here:
[img]http://www.mitsubishiparts.net/catalog/mitsubishi/vortexgeneratorred265.jpg[/img]
But without the antenna in it. What do you think?
...[Puts flame suit on]...
I'm thinking of making my own "Vortex Generator" for the WRX out of fiberglass that would be like the EVO one seen here:
[img]http://www.mitsubishiparts.net/catalog/mitsubishi/vortexgeneratorred265.jpg[/img]
But without the antenna in it. What do you think?
...[Puts flame suit on]...
| WRXSIG | 04-26-2005 01:11 PM |
done right..itll look badass!
i wanted to look into getting one to see if it would fit but theyr like $250
i wanted to look into getting one to see if it would fit but theyr like $250
| lianregnif | 04-26-2005 01:12 PM |
what does a "vortex generator" do?
| lawn boy | 04-26-2005 01:13 PM |
I personally think that they're ugly
| subieworx | 04-26-2005 01:22 PM |
It wouldn't do anything without being properly matched to the specs of the sti or other large wing. For esthetics only it is too Sonic the Hedgehog for me.
| fireball_jones | 04-26-2005 01:36 PM |
[QUOTE=lianregnif]what does a "vortex generator" do?[/QUOTE]
Causes air to flow at a higher rate in a specific area, and used with a proper wing, should create more downforce.
Think of skyscrapers in a city, and how wind speed on the streets in between is greater than areas without skyscrapers. That's because they're giant vortex generators. You can use that channeled air to better create downforce or lift.
Causes air to flow at a higher rate in a specific area, and used with a proper wing, should create more downforce.
Think of skyscrapers in a city, and how wind speed on the streets in between is greater than areas without skyscrapers. That's because they're giant vortex generators. You can use that channeled air to better create downforce or lift.
| MB38 | 04-26-2005 01:46 PM |
[QUOTE=lianregnif]what does a "vortex generator" do?[/QUOTE]
Generates vortexes.
Generates vortexes.
| TopSpeed | 04-26-2005 01:50 PM |
[QUOTE=MB38]Generates vortexes.[/QUOTE]
That would be "vortices".
:D
-Porter-
That would be "vortices".
:D
-Porter-
| ibsailn | 04-26-2005 02:59 PM |
Not at all how they work
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[QUOTE=fireball_jones]Causes air to flow at a higher rate in a specific area, and used with a proper wing, should create more downforce.
Think of skyscrapers in a city, and how wind speed on the streets in between is greater than areas without skyscrapers. That's because they're giant vortex generators. You can use that channeled air to better create downforce or lift.[/QUOTE]
While it would be hard to argue that skyscraper do not generate vortices, this is not why it is windy between buildings. It is windy between buildings because a certain flowrate is being constricted thru the streets (acting as nozzles) and therefore the fluid (air) is accelerated. This is also not a good description of how the vortex generators create more flow to the wing.
We often use votex generators in model testing in my business (yacht design). We use them for slightly different reasons, but the theory is the same. The best layman explanation is similar to the dimples on a golfball. By generating vortices (turbulance), the flow stays attached to the surface longer and therefore drag is reduced. Also, in the case of the rear of the car, keeping the flow attached to the rear-sloping roof will help keep high velocity flow on the rear wing.
As far as having them be effective on a WRX, your guess is as good as mine. There is a parasitic drag caused by the vortex generators, so that would have to be overcome thru improved flow for them to be worthwhile. Whichout wind tunnel testing, it would be hard to know if they are helping or hurting.
Think of skyscrapers in a city, and how wind speed on the streets in between is greater than areas without skyscrapers. That's because they're giant vortex generators. You can use that channeled air to better create downforce or lift.[/QUOTE]
While it would be hard to argue that skyscraper do not generate vortices, this is not why it is windy between buildings. It is windy between buildings because a certain flowrate is being constricted thru the streets (acting as nozzles) and therefore the fluid (air) is accelerated. This is also not a good description of how the vortex generators create more flow to the wing.
We often use votex generators in model testing in my business (yacht design). We use them for slightly different reasons, but the theory is the same. The best layman explanation is similar to the dimples on a golfball. By generating vortices (turbulance), the flow stays attached to the surface longer and therefore drag is reduced. Also, in the case of the rear of the car, keeping the flow attached to the rear-sloping roof will help keep high velocity flow on the rear wing.
As far as having them be effective on a WRX, your guess is as good as mine. There is a parasitic drag caused by the vortex generators, so that would have to be overcome thru improved flow for them to be worthwhile. Whichout wind tunnel testing, it would be hard to know if they are helping or hurting.
| ranger5oh | 04-26-2005 03:49 PM |
Best way to describe vortices: They mess up the airflow... the "sloppy air" , just as ibsailin says, stays attached to the surface. Flow that seperates from the surface doesnt provide the correct aerodynamics for optimum downforce and minimum drag. This is the same reason fighter jet intakes are a few inches off the surface of the fuselage of the jet. (Note, I am an aero engineer for a military aircraft company)
Anyway, I dont thin kthis guy is interessted in the performance of them, nor am I. I love the look , and if you make a good set, I would be interested in buying one off you.
Thanks,
Anyway, I dont thin kthis guy is interessted in the performance of them, nor am I. I love the look , and if you make a good set, I would be interested in buying one off you.
Thanks,
| KAX | 04-26-2005 04:15 PM |
as i knew it when i first saw these vortex generators... give it a few months, every civic will have one. I dont think it will be worth anything for your car, dont bother
| offset | 04-26-2005 04:46 PM |
(Slight tangent) So going forward with the thought on what a vortex generator would be used for on a car; it wouldn't make sense with an STi from what I can gather. I tend to believe that the point of the STi wing is less about downforce and more about lowering the overall drag coefficient by smoothing out the air. So disrupting the air even more before the STi wing would make the wing less efficient for its intended purpose. At least that is the way I am interpreting things. (off tangent)
So what is the point of the WRX wing? I would tend to believe it is closer to improving downforce than lessening drag. However I don't know that it sits high enough to catch and benefit from the vortex generated air flow. It would certainly be interesting to see in a wind tunnel, but that is the problem that I believe a wind tunnel would be the only way to know and they ain't happening.
offset
So what is the point of the WRX wing? I would tend to believe it is closer to improving downforce than lessening drag. However I don't know that it sits high enough to catch and benefit from the vortex generated air flow. It would certainly be interesting to see in a wind tunnel, but that is the problem that I believe a wind tunnel would be the only way to know and they ain't happening.
offset
| V6TurboTA | 04-26-2005 04:49 PM |
[QUOTE=brcewane]Hey guys,
I'm thinking of making my own "Vortex Generator" for the WRX out of fiberglass that would be like the EVO one seen here:
[img]http://www.mitsubishiparts.net/catalog/mitsubishi/vortexgeneratorred265.jpg[/img]
But without the antenna in it. What do you think?
...[Puts flame suit on]...[/QUOTE]
I like the idea and would love to see how it comes out.
~v6
I'm thinking of making my own "Vortex Generator" for the WRX out of fiberglass that would be like the EVO one seen here:
[img]http://www.mitsubishiparts.net/catalog/mitsubishi/vortexgeneratorred265.jpg[/img]
But without the antenna in it. What do you think?
...[Puts flame suit on]...[/QUOTE]
I like the idea and would love to see how it comes out.
~v6
| Handsdown | 04-26-2005 04:50 PM |
subaru's already working on vortex generators...
[img]http://x2.putfile.com/3/7515401889.jpg[/img]
[img]http://x2.putfile.com/3/7515401889.jpg[/img]
| volleybrad | 04-26-2005 05:01 PM |
[QUOTE=Handsdown]subaru's already working on vortex generators...
[img]http://x2.putfile.com/3/7515401889.jpg[/img][/QUOTE]
Aren't those made by Adobe? :lol:
[img]http://x2.putfile.com/3/7515401889.jpg[/img][/QUOTE]
Aren't those made by Adobe? :lol:
| WRX450 | 04-26-2005 05:07 PM |
too bad
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That wasn't even a valiant attempt at a photo manipulation... :(
| Handsdown | 04-26-2005 05:54 PM |
you're right, it was a photo manipulation with intent of horseplay and general silliness... sorry i'm not valient enough for you!:D
| fireball_jones | 04-26-2005 08:40 PM |
[QUOTE=ibsailn]While it would be hard to argue that skyscraper do not generate vortices, this is not why it is windy between buildings. It is windy between buildings because a certain flowrate is being constricted thru the streets (acting as nozzles) and therefore the fluid (air) is accelerated. This is also not a good description of how the vortex generators create more flow to the wing.
[/QUOTE]
My bad, half way through typing that my brain mixed up vortex and the venturi effect :p
I've never read anything that said they had any definite effect on the Evo, let alone what they would do to an STi. But they do look cool.
[/QUOTE]
My bad, half way through typing that my brain mixed up vortex and the venturi effect :p
I've never read anything that said they had any definite effect on the Evo, let alone what they would do to an STi. But they do look cool.
| flicky30 | 04-26-2005 08:43 PM |
That is THE MOST rediculous photochop ever. Wow, that's one I'll have to "right click and save picture as"
| Golfa | 04-26-2005 10:37 PM |
i like the wrap-around taillight effect :)
| JIN | 04-26-2005 10:47 PM |
They actually made vortex g for the subies. In fact, I have seen a couple of them around in the subies here in Singapore. Even saw one in carbon fiber too ... really nice.
Jin
Jin
| moss | 04-26-2005 10:50 PM |
[QUOTE=JIN]They actually made vortex g for the subies. In fact, I have seen a couple of them around in the subies here in Singapore. Even saw one in carbon fiber too ... really nice.
Jin[/QUOTE]
Its your job to get a picture ;) any for the GCs :D
keith
Jin[/QUOTE]
Its your job to get a picture ;) any for the GCs :D
keith
| twizzstyle | 04-26-2005 11:02 PM |
[QUOTE=fireball_jones]Causes air to flow at a higher rate in a specific area, and used with a proper wing, should create more downforce.[/QUOTE]
You couldn't be more wrong, sorry! :p
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)
You couldn't be more wrong, sorry! :p
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)
| kheovnien | 04-27-2005 02:34 AM |
[QUOTE=volleybrad]Aren't those made by Adobe? :lol:[/QUOTE]
ya, and adobe lost money on this investment, thus the small number produced.
ya, and adobe lost money on this investment, thus the small number produced.
| MikeBuzzsaw | 04-27-2005 02:48 AM |
[QUOTE=twizzstyle]You couldn't be more wrong, sorry! :p
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)[/QUOTE]
Its like communism. In THEORY, it will help you reduce drag, but in real life, no1 has seen an increase in anything.
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)[/QUOTE]
Its like communism. In THEORY, it will help you reduce drag, but in real life, no1 has seen an increase in anything.
| 909 | 04-27-2005 04:30 AM |
You might laugh, but I wonder if the EVO one would fit on our cars? Honestly, the countour probably isn't that off and the width is probably really close to the same!
Does Mitsu sell these?
Does Mitsu sell these?
| subieworx | 04-27-2005 08:03 AM |
[QUOTE=MikeBuzzsaw]Its like communism. In THEORY, it will help you reduce drag, but in real life, no1 has seen an increase in anything.[/QUOTE]
Official statement from Mitsu was that they were supposed to an effect on the air flow so that it would lift enoughto contact the top of the wing instead of allowing the air to go under it.
Official statement from Mitsu was that they were supposed to an effect on the air flow so that it would lift enoughto contact the top of the wing instead of allowing the air to go under it.
| subieworx | 04-27-2005 08:03 AM |
[QUOTE=909]You might laugh, but I wonder if the EVO one would fit on our cars? Honestly, the countour probably isn't that off and the width is probably really close to the same!
Does Mitsu sell these?[/QUOTE]
Other than the big stupid antenna mount in the middle. I will check this weekend. My friend has on on his Evo.
Does Mitsu sell these?[/QUOTE]
Other than the big stupid antenna mount in the middle. I will check this weekend. My friend has on on his Evo.
| brcewane | 04-27-2005 09:37 AM |
You can buy them in the EVO section of [url]http://www.gruppe-s.com[/url] for $310. I just figured that I've done a bunch of stuff in fiberglass before and I would try my hand at this one... just something fun to add to the car. If only we had the rear antenna like the EVO instead of that damn driverside retractable one that reminds me of my wife's CRV :(
| paperchasin | 04-27-2005 10:12 AM |
will simply look like rice...repeat of the altezza tail lights...
| Zor | 04-27-2005 10:32 AM |
[QUOTE=twizzstyle]You couldn't be more wrong, sorry! :p
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)[/QUOTE]
Those small fins on fighters are to stop the air from slide to the outside of the wing, also winglets reduce wingtip vortices, the twin tornados formed by the difference between the pressure on the upper surface of an airplane's wing and that on the lower surface. High pressure on the lower surface creates a natural airflow that makes its way to the wingtip and curls upward around it. When flow around the wingtips streams out behind the airplane, a vortex is formed. These twisters represent an energy loss and are strong enough to flip airplanes that blunder into them.
[img]http://www.b737.org.uk/737winglets.jpg[/img]
Winglets produce an especially good performance boost for jets by reducing drag, and that reduction could translate into marginally higher cruise speed. But most operators take advantage of the drag reduction by throttling back to normal speed and pocketing the fuel savings.
this ends today's lesson in aircraft :D
Vortex generators generate tip vortices that trail behind them. What this does essentially is delay boundary layer separation, and thus delays stall. On an airplane wing, they are no more than small fins of aluminum. In fact, this would probably be more effective than these "thicker" ones. But the idea is the same. Having these on a car has a similar result as a spoiler in that location (like on the back of SUVs). Basically, it keeps the air from seperating as much, decreasing drag (the majority of drag on an object is the result of flow separation on the back)[/QUOTE]
Those small fins on fighters are to stop the air from slide to the outside of the wing, also winglets reduce wingtip vortices, the twin tornados formed by the difference between the pressure on the upper surface of an airplane's wing and that on the lower surface. High pressure on the lower surface creates a natural airflow that makes its way to the wingtip and curls upward around it. When flow around the wingtips streams out behind the airplane, a vortex is formed. These twisters represent an energy loss and are strong enough to flip airplanes that blunder into them.
[img]http://www.b737.org.uk/737winglets.jpg[/img]
Winglets produce an especially good performance boost for jets by reducing drag, and that reduction could translate into marginally higher cruise speed. But most operators take advantage of the drag reduction by throttling back to normal speed and pocketing the fuel savings.
this ends today's lesson in aircraft :D
| Jejunum | 04-27-2005 11:44 AM |
why dont all aircrafts have winglets?
| volleybrad | 04-27-2005 12:02 PM |
why don't all buffalos have winglets?
| KAX | 04-27-2005 12:04 PM |
why dont i have winglets?
| Jejunum | 04-27-2005 12:11 PM |
it was a legitimate question - if winglets are so beneficial on airplanes woudlnt we see retrofitting of old aircraft with them?
| ATX25RS | 04-27-2005 01:18 PM |
[QUOTE=Jejunum]it was a legitimate question - if winglets are so beneficial on airplanes woudlnt we see retrofitting of old aircraft with them?[/QUOTE]
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
| 03twrx | 04-27-2005 01:23 PM |
Someone please photo shop winglets on something stupid. Like a Civic or bird or whatever.
| Zor | 04-27-2005 02:19 PM |
[QUOTE=Jejunum]it was a legitimate question - if winglets are so beneficial on airplanes woudlnt we see retrofitting of old aircraft with them?[/QUOTE]
because you would have to recontruct the whole wing to support the winglets.
on a 737 the winglets are 6 feet tall.
on a 747 Jumbo Jet they are 12 feet tall.
most of the older aircraft can't support this type of weight on the wing tip
because you would have to recontruct the whole wing to support the winglets.
on a 737 the winglets are 6 feet tall.
on a 747 Jumbo Jet they are 12 feet tall.
most of the older aircraft can't support this type of weight on the wing tip
| ibsailn | 04-27-2005 02:19 PM |
Oh Boy.....winglets on the end of lifting foils (wings) and the things on the EVO have NOTHING to do with each other. While I design for items in water (still a fluid like air). Winglets on the end of lifting foils (airplane wing or sailboat keel) help reduce induced (lift based) drag at the expense of increased frictional and form drag. If properly designed they can be quite effective. Winglet design for airlplane wings is a bit simpler because the foil is always lifting the same direction (unlike a keel which has to tack). I am not sure why all plane wings don't have winglets, but it probably is because for certain speeds/wing arrangements/uses, the winglets don't provide enough of a benefit for the added cost of design and construction. In boats, most keels don't have winglets because for them to be truly effective, you have to spend upwards of $30,000 on research to design the winglet properly.
I would not call a winglet a vortex generator. While it does create a votex which is much smaller than the normal vortex off the end of the keel, creating that smaller votex is not its primary purpose. I also wouldn't call the items on the back of the EVO Vortex Generators. I would call them turbulance generators (but the marketing guys would object because we all think of turbulance as a bad thing). As explained before, the purpose of the Vortex (turbulance) generators is to keep the flow attached to the surface for as long as possible. This will certiainly reduce drag and will probably make the wing more effective as a downforce generator. The purpose of a winglet is to reduce the size of the tip vortex and recover some of that energy into lift thereby reducing induced drag by allowing a smaller angle of attack.
Hope this helps.
I would not call a winglet a vortex generator. While it does create a votex which is much smaller than the normal vortex off the end of the keel, creating that smaller votex is not its primary purpose. I also wouldn't call the items on the back of the EVO Vortex Generators. I would call them turbulance generators (but the marketing guys would object because we all think of turbulance as a bad thing). As explained before, the purpose of the Vortex (turbulance) generators is to keep the flow attached to the surface for as long as possible. This will certiainly reduce drag and will probably make the wing more effective as a downforce generator. The purpose of a winglet is to reduce the size of the tip vortex and recover some of that energy into lift thereby reducing induced drag by allowing a smaller angle of attack.
Hope this helps.
| Zor | 04-27-2005 02:30 PM |
I would have to say they cause some drag on the roof of the evo, but type of drag creates a downforce as well so its some what of a trade off.
| MikeBuzzsaw | 04-27-2005 03:07 PM |
[QUOTE=subieworx]Official statement from Mitsu was that they were supposed to an effect on the air flow so that it would lift enoughto contact the top of the wing instead of allowing the air to go under it.[/QUOTE]
To me,that was a bunch of whoy. I have yet to hear praise from track drivers, magazines, etc about the effectiveness of the hedgehog like fin on the top of MRs. But it does look nice.
To me,that was a bunch of whoy. I have yet to hear praise from track drivers, magazines, etc about the effectiveness of the hedgehog like fin on the top of MRs. But it does look nice.
| KAX | 04-27-2005 03:31 PM |
[QUOTE=MikeBuzzsaw]To me,that was a bunch of whoy. I have yet to hear praise from track drivers, magazines, etc about the effectiveness of the hedgehog like fin on the top of MRs. But it does look nice.[/QUOTE]
i agree, i think this little thing does very little, much to the same extent as some people veiw the STi wing. Its a combination of an attempt to do something to the aerodynamics of the car, and giving it something that will stand out from the rest. More looks than performance.
i agree, i think this little thing does very little, much to the same extent as some people veiw the STi wing. Its a combination of an attempt to do something to the aerodynamics of the car, and giving it something that will stand out from the rest. More looks than performance.
| offset | 04-27-2005 04:38 PM |
[QUOTE=MikeBuzzsaw]But it does look [B]rice[/B].[/QUOTE]
Corrected that for you :p
offset
Corrected that for you :p
offset
| twizzstyle | 04-28-2005 12:13 PM |
Which is odd, because the wing will be more effective if there is more air going under it than over :confused:
[QUOTE=subieworx]Official statement from Mitsu was that they were supposed to an effect on the air flow so that it would lift enoughto contact the top of the wing instead of allowing the air to go under it.[/QUOTE]
As for retrofitting older planes with winglets, they are doing it all the time. I see older 737's with huge winglets installed these days, looks a little goofy to me but they do the trick. Winglets *effectively* add more wingspan (increase aspect ratio) which, as was said, decreases induced drag and increases L/D. But again, totally unrelated to vortex generators.
Seems like there's a surprising number of aeronautical engineers on here? :D How many? Me = 1.
[QUOTE=subieworx]Official statement from Mitsu was that they were supposed to an effect on the air flow so that it would lift enoughto contact the top of the wing instead of allowing the air to go under it.[/QUOTE]
As for retrofitting older planes with winglets, they are doing it all the time. I see older 737's with huge winglets installed these days, looks a little goofy to me but they do the trick. Winglets *effectively* add more wingspan (increase aspect ratio) which, as was said, decreases induced drag and increases L/D. But again, totally unrelated to vortex generators.
Seems like there's a surprising number of aeronautical engineers on here? :D How many? Me = 1.
| rich728 | 04-28-2005 12:20 PM |
Let's see a photochop STi with winglets everywhere, scoop, mirrors, wing tip...
| Smitty in VA | 04-28-2005 12:21 PM |
Here is what Mitsubishi has to say about it:
[url]http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf[/url]
[url]http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf[/url]
| ibsailn | 04-29-2005 09:04 AM |
[QUOTE=twizzstyle]Seems like there's a surprising number of aeronautical engineers on here? :D How many? Me = 1.[/QUOTE]
Not Aeronautical....just Nautical.... Count me for one Naval Architect/Marine Engineer.
Not Aeronautical....just Nautical.... Count me for one Naval Architect/Marine Engineer.
| fireball_jones | 04-29-2005 09:54 AM |
[QUOTE=Smitty in VA]Here is what Mitsubishi has to say about it:
[url]http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf[/url][/QUOTE]
Cool link, but it appears the VGs only decrease the drag coefficient by .006. Can one of the engineers on here say if that's alot for a car?
It also appears that I wasn't entirely wrong, since less seperation on the rear window provides greater flow to the rear spoiler, and decreases lift.
[url]http://www.mitsubishi-motors.com/corporate/about_us/technology/review/e/pdf/2004/16E_03.pdf[/url][/QUOTE]
Cool link, but it appears the VGs only decrease the drag coefficient by .006. Can one of the engineers on here say if that's alot for a car?
It also appears that I wasn't entirely wrong, since less seperation on the rear window provides greater flow to the rear spoiler, and decreases lift.
| Calamity Jesus | 04-29-2005 10:10 AM |
[QUOTE=fireball_jones]Cool link, but it appears the VGs only decrease the drag coefficient by .006. Can one of the engineers on here say if that's alot for a car?[/QUOTE]
I'm no engineer.. but we're usually given drag coefficients in the .3x to .4x range.. so that's a notible difference.
Drag coefficient of current models:
Prius: 0.26
WRX STi & Lancer Evo: 0.33
H2: 0.57+
When you look at the Prius as the current ideal, a .006 reduction is like an 8% drop towards that goal for the Evo.
I'm no engineer.. but we're usually given drag coefficients in the .3x to .4x range.. so that's a notible difference.
Drag coefficient of current models:
Prius: 0.26
WRX STi & Lancer Evo: 0.33
H2: 0.57+
When you look at the Prius as the current ideal, a .006 reduction is like an 8% drop towards that goal for the Evo.
| subieworx | 04-29-2005 10:35 AM |
[QUOTE=Beaverboy]I'm no engineer.. but we're usually given drag coefficients in the .3x to .4x range.. so that's a notible difference.
Drag coefficient of current models:
Prius: 0.26
WRX STi & Lancer Evo: 0.33
H2: 0.57+
When you look at the Prius as the current ideal, a .006 reduction is like an 8% drop towards that goal for the Evo.[/QUOTE]
It's actually a little under a 2% drop.
Drag coefficient of current models:
Prius: 0.26
WRX STi & Lancer Evo: 0.33
H2: 0.57+
When you look at the Prius as the current ideal, a .006 reduction is like an 8% drop towards that goal for the Evo.[/QUOTE]
It's actually a little under a 2% drop.
| Calamity Jesus | 04-29-2005 10:42 AM |
[QUOTE=subieworx]It's actually a little under a 2% drop.[/QUOTE]
Yes, an overall 1.8% drop, but I wasn't talking about the overall. :D
Yes, an overall 1.8% drop, but I wasn't talking about the overall. :D
| af9000 | 04-29-2005 11:46 AM |
There really are lots of engineers on here....(I'm a mech guy, although I did a lot of aerospace courses)
I'll say that the description of the winglets is right on, but you can't put a winglet in the same basket as vortex generators (VG's). The purpose of a winglet is in fact to [I]reduce[/I] the size of the vortex that is generated off the wing tips of aircraft. This gives the benefits that some of you described (reduced drag resulting in increased fuel economy etc etc)
VG's essentially add energy to the boundary layer - the layer of air next to the surface of the car or wing - and delay the separation of that layer. They are most well-known for their use on aircraft wings - look out the wing next time you fly somewhere and you'll see a bunch of little metal 'fins' that look bolted onto the surface. These [I]create[/I] little vortices that allow the wing to achieve a higher angle of attack without stalling.
In short, VG's keep the boundary layer attached longer down the back side of the car. This would give the spoiler cleaner air flow and possibly increase its effectiveness. This would only have a useful effect at [B]high speed[/B], like for WRC and other racing applications. For those of us that spend most of our time on the slower side vortex generators would be purely aesthetic.
cheers
I'll say that the description of the winglets is right on, but you can't put a winglet in the same basket as vortex generators (VG's). The purpose of a winglet is in fact to [I]reduce[/I] the size of the vortex that is generated off the wing tips of aircraft. This gives the benefits that some of you described (reduced drag resulting in increased fuel economy etc etc)
VG's essentially add energy to the boundary layer - the layer of air next to the surface of the car or wing - and delay the separation of that layer. They are most well-known for their use on aircraft wings - look out the wing next time you fly somewhere and you'll see a bunch of little metal 'fins' that look bolted onto the surface. These [I]create[/I] little vortices that allow the wing to achieve a higher angle of attack without stalling.
In short, VG's keep the boundary layer attached longer down the back side of the car. This would give the spoiler cleaner air flow and possibly increase its effectiveness. This would only have a useful effect at [B]high speed[/B], like for WRC and other racing applications. For those of us that spend most of our time on the slower side vortex generators would be purely aesthetic.
cheers
| fireball_jones | 04-29-2005 11:52 AM |
Yeah, the Mitsu tech article says the wind tunnel testing was done at ~110 mph.
| Tkacik | 04-29-2005 12:58 PM |
I think they look kinda cool.
| 2fas4u | 12-28-2005 08:56 PM |
That makes sense. At highway speeds the amount of down force we receive is really negliable. If it gets too high we sacrifice fuel efficiency. At 100 mph + the wing and any helping device for that wing's efficiency greatly increases down force.
| Magnum626 | 12-29-2005 12:14 AM |
All in all unless they're tested with our cars who knows if it'lll work correctly, either with the wrx wing or the sti wing or even wingless correct?
Chargespeed has one..
[URL=http://www.z1auto.com/prodmore.asp?model=wrx&cat=exterior&prodid=1638]chargespeed vortex[/URL]
[IMG]http://www.z1auto.com/images/chargespeedgdb_roof_2.jpg[/IMG]
[IMG]http://www.z1auto.com/images/chargespeedgdb_roof_1.jpg[/IMG]
Chargespeed has one..
[URL=http://www.z1auto.com/prodmore.asp?model=wrx&cat=exterior&prodid=1638]chargespeed vortex[/URL]
[IMG]http://www.z1auto.com/images/chargespeedgdb_roof_2.jpg[/IMG]
[IMG]http://www.z1auto.com/images/chargespeedgdb_roof_1.jpg[/IMG]
| njskatchmo | 12-29-2005 02:46 AM |
I've seen these for sale for WRX's. That's all the help I can offer.
| speedDman1 | 12-29-2005 01:08 PM |
doesnt the 2006 wrx sti have one of those "vortex" generators?
| Jsunn | 12-29-2005 02:20 PM |
there are two types of flow, laminar flow and turbulent flow. Laminar flow requires more energy to stay attached to a surface. Turbulant flow requires less energy to stay attached to a surface. The longer the flow stays attached to a surface the lower the profile drag (drag caused by the separation of both laminar and turbulent fluid flow from a surface, the wake of a boat is a good example.)
A vortex generator increases the energy in the turbulent boundary layer therefore it stays attached to the surface of the car longer and reduces drag. I would also suggest that it increases the usable airflow over the wing.
Whether the EVO's VG's are of the right shape/size or effective at all remains to be seen. I would like to see some wind tunnel footage it if it exists.
-J
A vortex generator increases the energy in the turbulent boundary layer therefore it stays attached to the surface of the car longer and reduces drag. I would also suggest that it increases the usable airflow over the wing.
Whether the EVO's VG's are of the right shape/size or effective at all remains to be seen. I would like to see some wind tunnel footage it if it exists.
-J
| EagleRockWrex | 12-29-2005 02:25 PM |
Generates vortexes, gayness and uglyness....
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