diy vortex generators

[momorris]

I was wondering today (and I think I have this right) the idea is to get rid of the drag behind the car, boat tail best, kammback another option. However my car is vertical on the rear

New Kia Picanto in Lakeside and Southend | Essex Auto Group

As neither of the above is an option what about creating a vortex behind the car. Could a strip of this across the back have any effect?

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[dcb]

Tested: hatch spoiler vs. vortex generators vs. stock hatch, 1996 Ford Aspire

Random lumps attached to your vehicle are not likely to have any positive effect. Vortex generators used on airplanes cause more drag but allow more effective control surfaces. Vortex generators on cars seem to cause more drag, and they don't have control surfaces.

[moorecomp]

Yes, it will keep burglars and cats from climbing on your car.

[ChazInMT]

Mo, the only thing you can do to improve your aero here is to make your car longer in the back. It already is a very aerodynamic shape, it is just very short. Doing anything aero in the back part of your car, other than building a plan taper rear extension, will in all likelihood hurt your mileage, or waste your time, money & effort.

[ConnClark]

MoMoris,

The airtabs inventor actually tested them in a wind tunnel on a hatchback. He showed a 4% reduction in drag. This however was done by a professional and not an amateur.

they have some of the results in a pdf but no photos of the placement http://www.airtab.com/MicrosoftWordHondaWTReportV6.pdf

They can work. You may need a wind tunnel to get it right however.

[dcb]

This thread inspired me to dredge up another concept, I see these were only tested on the sides, and would like to have an understanding of why rounded sides are everywhere when perhaps a sharp transition would be better. If the sides should be sharp for best aero (once the efficiency/handling compromises are understood) then that would seem a less complicated mod or one more likely to give results. A clear strip of plexiglass glued to the rear sides might suffice. Mini-boattail

But we don't know for sure if these specially designed VG would help on the top, the author speculates there.

Why so many rounded corners on the TE?

[momorris]

Thats an interesting read and seems that it should be possible then. It was just something I was considering giving a shot. After all we dont truly know untill we try it.

The kia has a curved side as well. I may try the sharp edges idea and extend the roofline for a few runs.

The mitsubishi evos use vortex generators on the MR

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A really good article here:

http://www.mitsubishi-motors.com/cor...004/16E_03.pdf



But for now its back to making some more smooth wheels after my first attempt disapeared. the undertray is complete and will be refitted after my master cylinder change. If I see an improvement then im going to remove the coroplat tray and mesh and fibreglass for a better finish.



Edited to add with a daily commute of 150 miles total every little helps

[euromodder]

So far, nobody on here has been able to get better fuel economy with vortex generators.
They do help to smooth the airflow, but seem to also introduce extra drag canceling out their positive effect.

[aerohead]

Originally Posted by dcb

This thread inspired me to dredge up another concept, I see these were only tested on the sides, and would like to have an understanding of why rounded sides are everywhere when perhaps a sharp transition would be better. If the sides should be sharp for best aero (once the efficiency/handling compromises are understood) then that would seem a less complicated mod or one more likely to give results. A clear strip of plexiglass glued to the rear sides might suffice. Mini-boattail

But we don't know for sure if these specially designed VG would help on the top, the author speculates there.

Why so many rounded corners on the TE?

dcb,if you can snag a copy of Hucho's book ( any ) you'll find a very lengthy discussion on edge radii.And I think you'll find that it's not a 1-size-fits -all sort of technology, when comparing squareback,notchback,and fastback bodies.

[pnambic]

Originally Posted by dcb

This thread inspired me to dredge up another concept, I see these were only tested on the sides, and would like to have an understanding of why rounded sides are everywhere when perhaps a sharp transition would be better...[/url]

Mainly because its the look the public has been going for. You have to remember that most people, however simple minded they may be, buy cars based on how they like they look first and foremost and car manufacturers are well aware of this. Plus, if it "looks" aerodynamic to the untrained plebeian eye, they assume it is. Most people assume smooth curves = aerodynamic when we here know this to not necessarily always be the case. Curves are good and have their places - just not everywhere. (I can think of several places I really like curves....hahaha....but I digress.)