EV build aero.

[botsapper]

A modest aero proposal with practical cargo utility. Typical flexible PVC lower edging; bash-proof, ablative and easily replaced. Lightweight fluted plastic lower skirt panels, easily replaced. Your hinged top (w/ your solar panels) that could have adjustable angles depending on empty or full loads. The adjustable/hinged/sliding frame kit allows adjustable top angles according to your load/aero profile. Custom lightweight side panels or use tarp sides secured with rubber tarp straps.



...DynaMax trike 2

[aerohead]

Here is the Koenig/Kamm wind tunnel development model of the FKFS.
You can see how they made the provision to truncate the boat tail at a number of locations.
Here is Heald's car of 1933.The roofline is too fast and he only scores Cd 0.20

Here is the Schl'o'rwagen,with more relaxed roofline and Cd 0.186

Here is one of Buchheim et al.'s VW aero models from 1981.

With the proper loft to the roofline,and Kamm's signature 'chop',they score Cd 0.15.
If you'll stay on the 'template' contour and then just slice off the tail where necessary,you'll have guaranteed attached flow.

[mistareno]

G'day.

Your photoshopping is far better than mine.

I was going to have the rear wheels completely enclosed and have the side panels hinged.

95% of the time it will be empty so I'm going to concentrate on the aero in the down position.

When it's up the tarp side idea is what I had planned, but to make it fit neatly, It would have to be designed for just one position - ie - fully up.

On a side note, the Schl'o'rwagen has a much steeper tail section than the template, yet still has a very low cd? Does it suffer flow separation?

The Schl'o'rwagen has a side profile that fits my wheelbase much better.

[mistareno]

If I use the Schl'o'rwagen template, it would look a bit like this.

The addition of an ecomodder sticker must reduce the drag coefficient by at least .02....

[freebeard]

This is Neil Blanchard's CarBEN EV5



If the outer 1/4s of the body were permanent and the middle 1/2 hinged open like this, it could create what's called a trolley top.

Else you could use a combination latch/hinge, two or three to a side, that would act like the hood on early 50s International trucks or late 40s Buicks. They open from either side, or you can flip all the latches and take it clear off. I used the idea in this dune buggy design:



You'd want no more than 1/2 to open this way.

[mistareno]

I was thinking gull wing style doors could be an option.

I could do something like the image below, but the entire sides.

[freebeard]

The problem will be fitting a straight hinge line on the compound curve shape. Maybe some inspiration here?

[aerohead]

Originally Posted by mistareno

G'day.

Your photoshopping is far better than mine.

I was going to have the rear wheels completely enclosed and have the side panels hinged.

95% of the time it will be empty so I'm going to concentrate on the aero in the down position.

When it's up the tarp side idea is what I had planned, but to make it fit neatly, It would have to be designed for just one position - ie - fully up.

On a side note, the Schl'o'rwagen has a much steeper tail section than the template, yet still has a very low cd? Does it suffer flow separation?

The Schl'o'rwagen has a side profile that fits my wheelbase much better.

At Cd 0.186,the pillbug is pretty sweet.The hash marks I've drawn in behind it designate the area compromising the boundary layer.A down-slope of 22-degrees is the maximum the boundary layer can tolerate.Buchheim found that at 23-degrees,the wake becomes that of a squareback.

If you stay on 'Template' you can get to Cd 0.13-0.12.With wheel fairings you can approach Cd 0.08.Here is the 2013 Cambridge University Eco Racer (CUER),with Cd 0.10.

For the lowest drag per length it's better to just truncate the 'Template' than pull the roof curvature into a steeper slope.The boundary layer cannot tolerate the increased pressure rise from the steeper slope,and will trigger flow separation and induce lift, exactly the thing we're trying to avoid.
Here is W.A.Mair's final boat tail schematic.Mair did special boat tail research and found the 22-degree angle to be superior.And you can see how much length he took before he got to 22-degrees.If you can follow my scribbling,you can assess the body drag at differing amounts of boat-tailing

[Xist]

If you wanted them big, you would have made them big!

Shall I do push-ups?

[mistareno]

If I follow the template as strictly as possible and chop off the tail where legislation dictates, I end up with the image below, which is similar to the outline of the design posted by xist-

Probably good because it has more space and will be easier to build.

A quick rough shot from the rear (it doesn't show curvature, but is probably how the basic 'frame' will look.