AirTabs shown to work by respected EM member

[Julian Edgar]

Originally Posted by aerohead

Julian,forgive me,as I'm quite late to the party,but can you please tell us the kind of car you're driving?
My mind was thinking in the direction of a notchback.I wanted to make sure.Thanks!

All is here: AutoSpeed - Fitting vortex generators to a three-box sedan

[aerohead]

Originally Posted by Julian Edgar

All is here: AutoSpeed - Fitting vortex generators to a three-box sedan

Thanks Julian!
Yes,these are exactly the type of vehicles which have demonstrated lower drag with VGs.

[freebeard]

Anybody have thoughts about testing air tabs in a wind tunnel/water flume?

Here's a video that covers the basics—nothing new—but does it with beautiful slo-mo florescent dyes in water:

http://www.youtube.com/watch?v=0ThQ_nD97hY

He concludes that water moving at 0.1m/s is equivalent to air moving at 2m/s.

[MetroMPG]

Originally Posted by aerohead

Julian,forgive me,as I'm quite late to the party,but can you please tell us the kind of car you're driving?
My mind was thinking in the direction of a notchback.I wanted to make sure.Thanks!

Phil - details here: http://www.autospeed.com/cms/A_113000/article.html

[Julian Edgar]

Originally Posted by MetroMPG

Phil - 1st generation Insight, details here: AutoSpeed - Blowing the Vortex, Part 4

No! Honda Legend.

[MetroMPG]

Oops - my mistake. Correct link: AutoSpeed - Fitting vortex generators to a three-box sedan

[redpoint5]

Wouldn't a coast-down test be perfect for testing the effectiveness of vortex generators? This would eliminate more of the variables inherent in tracking fuel economy and generate data that is more related to aerodynamic efficiency.

[Julian Edgar]

Originally Posted by redpoint5

Wouldn't a coast-down test be perfect for testing the effectiveness of vortex generators? This would eliminate more of the variables inherent in tracking fuel economy and generate data that is more related to aerodynamic efficiency.

I tried coast-down tests back in about 1988 when I first started playing with car aero, but quickly gave up. I found that they were nothing like as repeatable as (say) acceleration testing - the variation was large.

Happy to hear the results of other people's testing though - especially the spread of times with the car ostensibly identical.

[freebeard]

Around here (northwest of normal) we have the Van Duzer Corridor, where there are long downhill stretches of 2 lane road flanked by 80-120 foot tall trees. I'll bet around 4 AM it is really calm.

[aerohead]

Originally Posted by freebeard

Anybody have thoughts about testing air tabs in a wind tunnel/water flume?

Here's a video that covers the basics—nothing new—but does it with beautiful slo-mo florescent dyes in water:

He concludes that water moving at 0.1m/s is equivalent to air moving at 2m/s.

The wind tunnel might be preferable if it's already instrumented for drag under-floor measurements.
The water tunnel might require an overhead sting which would influence both the flow and measurements.
At full-scale you might be able to easily separate out the sting's influence,but with scale models small details are virtually never modeled with any hope of accuracy.I suspect that something as small as VGs would have their effects buried within the signal-to-noise ratio.
Large models would be more expensive than the full-scale vehicle.