Roof Scoops

[JacobLeSann]

So here’s the scoop,

I’ve ridden bicycles long before I’ve driven cars. These days I ride a scooter most of the warm season. I love the feeling of fresh air on my face.

Most of my cars have had sunroofs. When it’s very warm out, or even when it’s brisk outside in the fall, I like to open them up and feel the breeze. I don’t mind the noise either.

But they cause drag! And it’s a solid amount too. I could leave them closed and use my fans on cold (don’t have A/C or want it), but I love that breeze and need it on those blazing summer days.


So, what about this? Rally cars have used scoops like this since a while back. Could this be designed to be more efficient than cracking a window?



I love the look of it, as well as the functionality. I can see it leaking in rain/winter though.

[COcyclist]

My biggest fear would be cutting a hole in the roof that you cannot plug completely in winter. That and wind noise.

I find that the vents coupled with a window cracked on the passenger side gives lots of ventilation. Light clothing, shorts and a synthetic T shirts helps. I have experimented with a chiller pad, used for recovery from knee surgery, which runs off a small inverter and ice water from the convenience store. I put it on my neck and back and it will really cool you off. You can probably find one lightly used for cheap.

[freebeard]

You'll need a means of letting the air out.

[Cd]

Very nice Civic ! Cabon fiber !
I too like the look.
So you want more air to come into the cabin ?
I also have a Civic, and the vents have always been my only major gripe with these cars.

If you like the Sun, you would of coarse be killing that idea with the roof scoop.

You are also going to add more frontal area to the car.

Besides installing a more powerful blower for the vents, I'm wondering if a cowl induction setup would worj for you to drsw in more air.

Another option would be to install a NACA duct setup for the window.
I see you have aftermarket mirrors, and thst A pillar block off plate would be a good location for one.
It could be fashioned to mount in the gap you create when ypu roll down your window.

It would also go with the racing look of the car.

[kach22i]

Projects from Make: Magazine
Scoop Fresh Air Into Your Car with This Window Vent
Time Required: 8–16 Hours (A Weekend)Difficulty: EasyPrice: $20–$30
https://makezine.com/projects/scoop-...r-window-vent/

[JacobLeSann]

There’s an idea. I believe that same concept was used on the Mule VX build, if you guys recall. I think it belonged to “TheDonkeyCRX”? Anyway, he was ordered to get a side view mirror so he made a fake one that was actually a ducted air intake for the cabin. I feel like a roof-mounted intake could be sleeker and I know from rallycross info that it would get cleaner air. My dad’s Oldsmobile ‘88 had a vented intake in the fender well that delivered lots of cold air but it came with dust.

Haha, that’s not my civic! I do have an EG hatchback, but it is not carbon fiber nor is it nice looking. That image comes from a rallycross chassis build. Very cool. I don’t have the budget for carbon fiber but I’m learning how to get good with fibreglass for the same reason.

Frontal area is a big one. I guess it’s a matter of what costs more energy. For instance, I have aftermarket windows louvres on my 2006 civic coupe. They increase frontal area and drag. On the flip side, they let me keep my window cracked while driving and eliminate fogging/frosting that would normally require the heater or blower. Mechanical or aerodynamic drag? That’s the question. I’d think mechanical would be worse.

And exhaust is indeed important. I’ve read that the Honda EF chassis platform cars had a system like this, notably the ‘88-91 CRX HF. Sadly, nobody really takes pictures of it or talks about it. But it did have a ducted intake and exhaust for airflow through the car without having to roll the windshield down.


The practical solution is just side window louvres, but why not have something different? My friend, who works in the aerospace industry, was thinking of a sort of hinged NACA duct system. Sounds like it would have issues with sealing.

Food for thought.

[freebeard]

There were two reasons I picked the example in Permalink #3.

One was that the ventilator above the windshield has an opening that faces downward. Less rainwater ingested.

The other is the pop-out side windows. My 1990 Metro has those.

[aerohead]

If your local library can get you an inter-library loan of Sighard Hoerner's book, 'AERODYNAMIC DRAG,' he's got quite a bit of detailed aerodynamic results for a variety of scoops, complete with Cds for each kind.
In modern times, for raw harvesting power, the Baumann scoop, which you'll find on the P-38 Lightning aircraft, or NHRA Pro-Comp Top-Fuel funny cars are preferred. Since they're 'external,' their Cd and frontal area must be considered together.
The lowest drag inlet is the NACA submerged inlet, which requires special geometric considerations 'below the skin.'
Between the two, you may be able the calculate parasitic loads, or the lack thereof.
NASCAR uses NACA inlets behind the B-pillars, of which flex ducts are attached to route the flow inside the cabin.