Vortex generators Options

[retrotech]

Is there any new experience to report, about the effectiveness of using Vortex Generators?

[race914]

No track time since the April event. Going back to Buttonwillow 6/23-25.

Will be able to get some lap times to do a 'before & after' with the AirTabs.

In any case, for an investment of only $27.50, they sure look cool! (see #52 in the background)

[Joe Ricard]

I am ssssoooo waiting to see if there is any difference with Air tabs.
I am just about ready to get them just for the cool factor.

[race914]

For the June event I'm going to get some times with the airtabs, then switch tops with #25 and compare the times.

Without airtabs I can't stay full throttle in 5th going clockwise through the riverside turn. Rear end gets way too light and starts 'dancing'. Got my fingers crossed that the vortex generators will help get some air down to the rear spoiler!

(IMG:http://www.buttonwillowraceway.com/images/race_01_config.gif)

[Joe Ricard]

Man I wish I lived in Kalifornia. That is WAY bigger than NPR in Lousianna.

[Aaron Cox]

i saw an EVO with vortex genorators on its roof yesterday...

[Joe Ricard]

Well so much for that shit. If the ricers guys start putting them on then I will keep them off.

UNLESS someone has evidence of it really working. then I will just paint them flat black like the targa top.

[byndbad914]

Got my fingers crossed that the vortex generators will help get some air down to the rear spoiler!

That will be interesting to see if it really can get an effect down to the spoiler. Vortex generators work best with wings, or a rear spoiler/tail section that is high enough to have the tumbling air move over them.

My good friend I met in college works for Honda now, but previously worked for a couple of Indy car design places and he really knows a lot about aero, and he doesn't think it would make any difference with the spoiler with the way the rear is designed, though it may help with the overall lifting issue. I didn't really notice the lifting with my car until I was up around 130mph or so on the front stretch of Willow (I don't think you go that fast at Buttonwillow unless you remove the bus stop and go straight down the back). My car got a bit "darty" around 130 to 140-ish. I have a 6" Sheridan spoiler and was talking about adding those tabs to see what would happen and he said maybe with a spoiler that tall, but thought controlling the air under the car would be far more beneficial than the airtabs.

We both agreed it was worth a try though for $30. I am adding a wing to mine, so I will be getting those tabs as well and have 2 lids, so I will tab one and leave the other stock to compare. It will be awhile for me though... my friends rented Buttonwillow this Thursday and I thought my car would be done, but I have had a one-month setback that is just killing me (IMG:style_emoticons/default/mad.gif) That would have been 8hrs with only 14 other cars, but oh well!

[Randal]

No track time since the April event. Going back to Buttonwillow 6/23-25.

Will be able to get some lap times to do a 'before & after' with the AirTabs.

In any case, for an investment of only $27.50, they sure look cool! (see #52 in the background)

Where do you get these babies?

[byndbad914]

Where do you get these babies?

Here is a link that was posted elsewhere
http://www.buyairtab.com/index.php?main_pa...054559679f89fc2

[mikelsr]

A friend of mine is a retired engineering professor and we were talking about the vortex generators at one of our Porsche Saturday AM get togethers. He is very well known and respected in the engineering and PCA racing communities.

Here is what he said after I showed him a picture off the internet:

"What this picture shows are a type of vortex generator but these are WAY to
large! The next time you fly look out the window of the aircraft about where
the engines are mounted below the wings and you will see a row ( or two ) of
small one or two inch high hat appear to be tiny wings sticking out of the
wing and with a small angle to the flight direction. These produce vortices
which help keep the flow attached to the wing and increase lift

The add-on's in the picture you sent may make the owner happy but will only
increase the drag. I can't see that they will produce any help for any
thing."

[DanT]

wow, talk about a bummer.....

That last post kind of takes all the fun out of it... (IMG:style_emoticons/default/smile.gif)

[Trekkor]

...Except, our cars don't go 500mph.

I'd like to see some wind tunnel pics.


KT

[retrotech]

I started this thread, because I had intended to install the Factory Mitsubishi VG. The ones you are referring to are designed for Semi's, with long straight, flat panels. As I understood, they were trying to get clean release at the rear, to lessen drag. The smaller version on Mitsu. were developed, not just eye candy. There design is to keep air attached, reducing lift, and or keeping air in the vicinity of wing/spoiler.
I still think there is potential for improved stability at speed.

[brokenmoped]

i saw an EVO with vortex genorators on its roof yesterday...

That would be the EVO MR Edition. Comes from the factory like that. And they aren't just for looks either. The MR outperforms the Subaru STi, unlike the stock EVO.

[race914]

...Except, our cars don't go 500mph.

I'd like to see some wind tunnel pics.


KT

(IMG:style_emoticons/default/agree.gif)

I'm sure the stick on airtabs wouldn't do well at 737 speeds. Not sure if the airplane devices work well at ~120mph ? (IMG:style_emoticons/default/confused24.gif)


Here is the 'operational concept' from www.airtab.com

(IMG:http://www.airtab.com/Images/trailflo.gif)


Here is how my roof turned out


Will this help get airflow to the rear spoiler? Don't know... but worth a try for $27.50. The with & without laptimes will tell the story!

I'll post back after our June BW event.

[byndbad914]

I'm sure the stick on airtabs wouldn't do well at 737 speeds. Not sure if the airplane devices work well at ~120mph ? (IMG:style_emoticons/default/confused24.gif)

Here is the 'operational concept' from www.airtab.com

Will this help get airflow to the rear spoiler? Don't know... but worth a try for $27.50. The with & without laptimes will tell the story!

I'll post back after our June BW event.

I am very interested to see what you determine! I think the best way to know how well these work for you is if you can get up to high mph in a sweeper turn. BW only has one and it isn't really that long (not like T7 thru T8 at Willow Springs). If you get better rearend grip and can get a higher mph thru a sweeper, then those tabs are working. To clarify - if the car wants to oversteer at 105mph without the tabs, but you can run through at 105 or faster without oversteer with the tabs, then they are working.

I agree there will definitely be more drag with their size. The issue always exists with anything aero - how much drag can you handle v. increase to handling performance (though on a smaller degree with smaller generators). If you have the HP to pull the generators through the air, and they help you go faster, the driving benefit outweighed the drag cost.

Getting the air to tumble over the rear section of the car may just be enough to reduce the crazy lift the car creates otherwise. I will gladly pull them through the air to get that benefit. Hard to say without a wind tunnel (which who has one of those (IMG:style_emoticons/default/blink.gif) ) or just some good old fashioned testing. BTW, if you have a full scale wind tunnel in the SoCal area, you are my new best friend!! Probably have a whole new club of best friends (IMG:style_emoticons/default/biggrin.gif)

Speeds below 100mph are probably worthless as the car doesn't experience a bunch of lift at the rear anyway. Hard to hit speeds much above 100mph at BW though, just through the bus stop and the sweeper after it. But they go by so fast...

BEST OF LUCK - if they work a lot of us will benefit on the larger tracks like Willow Springs! (IMG:style_emoticons/default/driving.gif)

[Trekkor]

I'm going to say they make an improvement. (IMG:style_emoticons/default/thumb3d.gif)

KT

[brant]

numbers will tell.
all else is conjecture.

[sww914]

They're cute!