Interesting Aerodynamic Cars (Mike Vetter's ETV, also Avion)

[sgtlethargic]

Here's what looks to be an excellent webpage about one of the Sunswift Cruiser Class solar racecars. It's claimed that the Sunswift 7 has a 0.095 Cd. Compare that to one of the Bochum University cars (that's linked in the webpage) which is said to have a 0.135 Cd. The Sunswift has a much better Cd without having the teardop-shaped cab forward form, but it has an underbody duct from front to rear, whereas the Bochum's only have a rear duct. So, a through-duct seems to be a good way to get a very low Cd, but that adds challenges to setting up the drivetrain, passenger compartment, etc. I'm guessing that a combination of the Bochum (teardrop-shaped cab forward) and Sunswift (through-duct) might be better. In other words, mimic the Sunswift but make it cab forward. I'm hoping to try designing and building something similar to this for a fairly low-speed get to work and grocery getter, one of these years.

https://www.linkedin.com/pulse/sunsw...ng-graham-doig

[freebeard]

Compare with that line drawing:

https://i.ytimg.com/vi/SL7W1H8rfcA/maxresdefault.jpg

The underbody contour is flatter than the drawing.

I'm surprised by the those square corners on the windshield. And all the headroom and lack of tumblehome. The rocker panels show some influence by Morelli.

Why no corresponding notch in the roof?

[Logic]

Originally Posted by freebeard

Compare with that line drawing:

https://i.ytimg.com/vi/SL7W1H8rfcA/maxresdefault.jpg

The underbody contour is flatter than the drawing.

I'm surprised by the those square corners on the windshield. And all the headroom and lack of tumblehome. The rocker panels show some influence by Morelli.

Why no corresponding notch in the roof?

Probably because they are trying to be aero with SIMPLE Curves rather than the complex curves the cells wont 'bend' to.
Also they are trying to maximize solar area.

[freebeard]

Compound curves can be achieved through geodesics. I gave it my best shot here (ignore the backface culling):



That's a six-frequency octahedral sphere asymmetrically prolated (X and Y weighted to the front, Z weighted to the bottom for an ME-262 shark-like profile).

edit:
I hadn't thought about solarizing this design, but looking at it now, if the longitudinal edges are a continuous curve and the lateral edges are straight it produces a shape similar to Randy Grubb's Decopod scooters.

2nd edit:
Not saying areohead's Template is the be all/end all of slippery shapes. Ross Lovegrove follows Morelli:

[sgtlethargic]

Originally Posted by freebeard

Compare with that line drawing:
...
The underbody contour is flatter than the drawing.

I'm surprised by the those square corners on the windshield. And all the headroom and lack of tumblehome. The rocker panels show some influence by Morelli.

Why no corresponding notch in the roof?

The one the webpage is about is the Sunswift eVe. I mentioned the Sunswift 7 because that one mentioned a Cd.



The webpage describes much of the design decisions, based on CAD and CFD. If their reported Cd is correct, that's great.

[sgtlethargic]

Originally Posted by sgtlethargic

Here's what looks to be an excellent webpage about one of the Sunswift Cruiser Class solar racecars. It's claimed that the Sunswift 7 has a 0.095 Cd. ...

https://www.linkedin.com/pulse/sunsw...ng-graham-doig

If I end up building a car similar to the Bocruiser and the Sunswift eVe, I'd be sitting in the center, for safety, in case of a t-bone crash. I'd have to try to run two ducts on the sides of the centered floor (for lack of a better term).

The more difficult challenge would be to have front and rear ducts that are connected by those two side ducts, while having a FWD or RWD system and suspension. In other words, the center section ("pumpkin") of a standard differential would be in front or back, near the center, so that'd make whichever end it's on also split into two ducts (unless I can get the pumpkin and axles/housings up higher in the chassis than they usually are in cars). The positive part of that negative is that the pumpkin would be aligned with the centered floor. There are also the axles and/or axle housings on most FWD or RWD cars. That's unless I figure out how to have suspension a mechanism for driving one or two wheels without using a common differential axle.

Anyone have any thoughts on how to have a drive system that allows a full duct front and rear? If I end up using an electric motor, that'd probably make it easier to figure out.

[freebeard]

The examples that come to mind are the Aston Martin Valkyrie and the Colani C-Form.


https://prestigeandperformancecar.co...5-1240x775.jpg

[ennored]

Aero Honda Fit. As seen posted on Facebook Marketplace by user "Adam Pigeon" in Knoxville, TN.

Haven't see this car mentioned here?

Seems like it would need to be longer to work better?

(Not bothering with a link as it'd surely be dead soon.)

[RedDevil]

That's a tight Fit!

[Logic]

2 fans for active downforce = upside down capability!

https://www.youtube.com/watch?v=g6LYcgaQ46c

Also there is NOTHING that corners like this 'rollerskate'! Nothing!!
Plenty of videos showing that.