CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[BryanSr1]

Thanks for the Update as I followed in the beginning a lot
but Life happens and I just got back to the forum. I need to update my info.

[NeilBlanchard]

I have been contemplating taking CarBEN to a wind tunnel. I know I would have to put the back doors on it, and open up the slot exhaust vents on the back, and fasten in the windshield. Oh, and I have to fit the rear wheel skirts at least.

Do I need to fiberglass the whole outside?

Where is the nearest wind tunnel that can test a full size car?

[sendler]

I wonder if the national Research Council of Canada would be interested in testing your design in the tunnels at Ottawa?
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Wind tunnel testing facilities - National Research Council Canada
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[samwichse]

Originally Posted by NeilBlanchard

Do I need to fiberglass the whole outside?

Where is the nearest wind tunnel that can test a full size car?

I think you would at least need to smooth the surface... the porous foam will probably change the boundary layer considerably.

[Erasmo]

Yes. With some programs you can even do a lot yourself. With the right software and a phone camera you can do a decent approximate and tune before sending of the car.

[NeilBlanchard]

The scanning part is what I would need to find out about.

I did try CFD - and several other people did as well, on the SketchUp model but it is way too porous.

[freebeard]

The solution will be built on the Blender animation engine and OpenVDB. As things go, it shouldn't be too much longer.

A smart phone data capture would probably need massaging into an optimal form (polygon density, hard edges, etc.).

[aerohead]

Originally Posted by NeilBlanchard

I have been contemplating taking CarBEN to a wind tunnel. I know I would have to put the back doors on it, and open up the slot exhaust vents on the back, and fasten in the windshield. Oh, and I have to fit the rear wheel skirts at least.

Do I need to fiberglass the whole outside?

Where is the nearest wind tunnel that can test a full size car?

*I'd recommend at least one layer of glass to give some tensile strength to the skin.My 1st aero shell exploded at around 60-mph without it.
*Seems like the A2 tunnel in Mooresville,North Carolina would be the nearest that you could get into.And Gary Eaker offers a discounted rate of $470/hr for the 1st 2-hours.
*DARKO is modeled after A2 and once the car is mounted in the test section it takes only 4-minutes to get Cd and lift recorded.
*You could take some time with the smoke imaging to scrutinize the flow.

[freebeard]

Vinyl wrap.

[Galane]

Originally Posted by NeilBlanchard

I have been contemplating taking CarBEN to a wind tunnel. I know I would have to put the back doors on it, and open up the slot exhaust vents on the back, and fasten in the windshield. Oh, and I have to fit the rear wheel skirts at least.

Do I need to fiberglass the whole outside?

Where is the nearest wind tunnel that can test a full size car?

So you've decided against coating it with wood glue?

Glassing and making it smooth would be the best. If you don't have it as close to the finished surface as you can, the data from a wind tunnel test wouldn't be very useful.

Parts of the wing surface on the Voyager plane that flew around the world non-stop had a satin or matte finish. They calculated that the weight of filler and paint required to make those areas slick would more than offset the efficiency gain from the drag reduction. But Rutan had a bunch of people learned in the ways of airflow, and access to tools (and money) that folks like us don't. Yet all that didn't make any of the team smart enough to do a ground and taxi test with a full fuel load prior to the day of takeoff on the trip. So the wingtips ended up dragging and ground off enough of the composite and foam until the winglets fell off. Oops. Should've had little wheels or HDPE skids at the wingtips.

If you have the $$$ for multiple wind tunnel runs you could try different surface finishes to see the effect (if any) each has. But for practical purposes at common and legal road speeds for earthbound vehicles, you can't go wrong with making the surface as smooth as you can.

Or call up Scaled Composites and see if they'd be interested in having a look at your car.