NACA duct or scoop

[Cd]

Yes - a box cavity for sure.
An open cavity in need of filling.

I think I understand what you mean about the low pressure in the cavity defeating the purpose I had intended.

I hadn't thought of this, and I'd bet you are correct.
Since the airflow in the boudary layer back there is so weak, the airflow from inside the Kam - box cavity may even push airflow OUT.

I can't wait to test it. ( pressure testing especially, but I do not have the equipment. )
For now, I will just have to tuft test it.

I have already seen in a tuft test I did that tufts placed inside the cavity rise up and flow out the open areas behind the 3rd brake light.

[JulianEdgar]

Good luck! It's an interesting idea.

[Cd]

Thanks !
I plan to also try and channel air from under the front of the car to this area as well. ( the red area in the photo )
This is going to be a real 'drag' though, because there are so many things in the way, such as exhaust.
Under the engine firewall, I will try and channel some of the engine bay air into this duct as well.
Would air still have a ram air effect if ducted from the front of the car all the way to the rear ?
How does air react to bends, such as a 90 degree curve ( radiused of course )

[aerohead]

Originally Posted by Cd

So are the fatter style ducts ( see photo attached in post above ) less effective ?
By the looks of it, the fatter designs seem to be shallower.

If you happen to be passing by any Audi, you might want to peek underneath the front end. They use NACA submerged inlets at the, below-engine, ABS plastic belly pan section.