Ultravan as a Dymaxion?
 

I saw an Ultravan for the first time last weekend.

It seems to be fairly aero. It is made out of aluminum and supposedly fairly light.

Some google image pics:

http://www.nextautos.com/files/image...06.preview.jpg

http://hotrod205.files.wordpress.com...ultravan01.jpg

http://auto.freedomblogging.com/file.../ultravan3.jpg

http://i526.photobucket.com/albums/c...ltravan67b.jpg

http://media.photobucket.com/image/u...ltravan67f.jpg

After cleaning up the body, get rid of the awning and A/C, it might make a reasonably aero shape. Maybe drop a VW TDI in there.

This could be somewhat close to a Dymaxion type vehicle. Except for rear wheel steering, which is better left alone.

It lacks the gradual taper of the Dymaxion. Replacing the bubble back with a gentle taper and a kamm back would help a bit. The roof vents need fairing, too.

The British say "aluminium." :D

I dig the built-in rear wheel skirts!

Ehhhhhhh... Dymaxion like? Not so much.

compared to it's modern counterparts that's a thing of beauty! looks like a good starting point when all the junk on the top and the sides is shaved off.

that said it doesn't have a basic teardrop shape but rather rounded ends that works on the front, but it's less ideal at the back (think VW beetle).

this makes me wonder however...if you'd saw a Dymaxion in half and add a center section, limmo style, what would happen to the Cd?

The rear shape may be better than many realize. Remember, it's a camper. It's not supposed to go 70 mph. 50-60 may be too fast to enjoy the ride. Think blue highways. The speedo may spend a lot of time between 30 and 45. When you slow down air softens, and sticks to sharper final tapers. That body transitions very smoothly. No first derivative discontinuities and second order looks very low. As for stripping creature comforts for a small MPG gain - phooey! Meet the functional requirements of the vehicle and it's intended purpose first. Not getting any sleep suffocating in your own sweat sucks the fun right out of travel. :)

Cheers
KB

http://go2.wordpress.com/?id=725X134...ymaxion-car%2F

The tail end of the Ultravan is much wider than the Dymaxion.

However, the Dymaxion only seats four, while the Ultravan has much more interior room, enough to live in.

The Ultravans are relatively inexpensive and could be the base for an interesting ecomodmobile. However, they only come with Corvair engines and Chevy 350 V-8's, neither of which is a very good engine for fuel efficiency.

If one were to find an older Ultravan in rough shape, strip out and rebuild the interior to make it as light as possible, clean up the exterior and repower with a better motor, what type of mileage do you think it might get?

Clean up the exterior, or do a complete aero rebody with a narrow rear track?

I like boat tails, but putting heavy components in the tail moves the center of mass rearward with negative implications for crosswind stability and rear axle placement.

Cd would increase as the relative size of its wake increases. Frontal area would increase as well.

If you cut it at the maximum cross-sectional area, the Cd would rise a little due to inceased wetted area. You would, in effect, have made an aircraft fuselage. The frontal area would remain the same.