what are these stuck on Aero thingies?

[oil pan 4]

The only time they are going to help is if they are placed on the vehicle and studied in a wind tunnel. Or placed by someone who specializes in automotive aerodynamics and has spent a lot of time hanging out at the local wind tunnel.
These little things actually increase drag and what you are trying to do is place these drag increasing structures ahead of a very large drag increasing design feature, to try and reduce drag.

[mcrews]

Originally Posted by Fat Charlie

That is Frank Lee being nice.

unofficial guide to frank lee posts....

1 sentence - (regardless of words used) is nice

2 sentences - he's warm in up!

3 sentences - rember the duck and cover drills in elementary school?

(love ya Frank Lee!!

[elhigh]

Those air tabs can be helpful, but it takes testing to know whether how they are being deployed is helpful.

I 100% guarantee that there is a lot more to be gained on that truck without spending one red cent on VGs. For what the guy spent on VGs, he could have bought or made an air dam that likely does a lot better than what he has there.

Just the fact that his wide-open wheel well is still uncovered proves there's more gain to be had.

[Xist]

Don't take Frank Lee seriously, he is a Ford man. Apparently, there have not been enough kids trespassing on his lawn lately.

Frank, I hope you do not mind my kidding too much.

I see air tabs on semis. That industry has the money and motivation to pursue new technology, but I would not expect them to waste money on fads.

[Natalya]

I see them all the time on semis.

AutoSpeed - Blowing the Vortex, Part 4

[freebeard]

The aerodynamics of a 40ft long box van are different to a hatchback. There is a lot of length for reattachment of that kerfluffle that happens at the front.

[sid]

I tried them six years ago on the back of the topper on my pickup truck. I didn't notice any difference good or bad. I took them off after about six months because I got sick of people asking about them and they made it harder to wash and wax the truck.

[gumby79]

The A&P book I read said
VGs (Vortex Generator) are for maintaining attached airflow at excessive angle of attack preventing a stall.
Also that a VG should be placed 1/3 cord for of the point of separation. At 15° off of the direction of airflow (as apposed to direction of travel this could be 90°to the direction of travel.
The other day I saw a 53' reafer with a VG kit (1 pice per side with ~ 12 VG each) placed ~12-18 forward of the door hinges. The oddity was the VG s were orientated wide side leading like a NACA duct intake.(>--).. I think someone didn't read the instructions and installed the left pice on th right side .

----
VGs could be used to allow a steeper angle >12° on a camback/ aerocap (as in a short bed) with out requiring the cap to be truncated . The reasons given by other builders of aerocaps for a truncated cap was . To get down to the tailgate ment an angle too steep and would cause a loss of attached air flow . With some $500/hr wind tunnel time a 3' aerocap with VG is possable . As it stands now without VG s an 8'+ bed is needed to maintain the templates <12° change of surface angle for attached flow.
Gumby Stay Flexible

[gumby79]

AutoSpeed - Blowing the Vortex, Part 4
VG as i understand them. Running backwards as the article suggest seems counter productive as in this format it takes 2 VG each at opposite15°to air flow to achieve a single pair of counter rotating vortices ... 2 pucks =1 pair of vortices . And causes an increase of non aerodynamic frontal area. May as well glue bricks to the car ,there cheaper.
Turn them 180° and now you have 1 puck and 1pair of counter rotating vortices , and a streemlined additional frontal area. Much less math and drawing pictures on your car to figure out the proper orientation. based on tuft testing to determinethe befor during and after points of separation at various speeds to align the skinny end with the Wind(forward) . My choice after researching points to using a type2 skinny end with the Wind. With the skinny end aligned with the tuft ,putting the 2 tailes at +&- 15° to the air flow.

Their example of VG it the belly pan the vG action is more a saw tooth air dam . Showing a positive impact on aerodynamic efficiency. A better result wou have beenfrom a full air dam.
Their only use of tuft tested VG was on thire only non instant mpg . Making the visible improvement un measurable.

The CRX looking hatchbacks looks like the VG is located at the point of reattachment disturbing this reattachment. With no place for the vortex to stableize (hence the 1/3 forward its gota land and stableize before it can help). It appears as though this car could have shown improvement it the VG had been applied in a similar positions as the Insight and determined with tuft testing.

[acparker]

Found this while googling:

Aerodynamic Effects of Rear Spoiler and Vortex Generators on Passenger Cars

https://www.researchgate.net/profile...Passenger_Cars