CarBEN Model -- 1/24th scale model and 3D computer model for EV

[NeilBlanchard]

I have an old Image Shack account, so I'll use it for the time being:

[Patrick]

Neil, if it were me, instead of starting with the Boxfish shape, I think I would use something like the "4-seat Cabin Arrangement" shown in Figure 15 on page 10 (hardcopy page 9) in the following pdf. This design uses boundary layer control and aft-body thrust and has been shown to have 1/2 the drag of conventional fuselages. Since you are planning on entering from the back, you could just make the door opening at the boundary layer slot. Leave the fan off around town, then turn it on when you reach 30-40 mph where the aerodynamic drag starts to become a factor. You could use a 3-wheel configuration or perhaps lower the nose area and/or flatten the bottom to have 4 wheels enclosed without too much drag increase, I think. This design has a lot of interior volume while miniminizing aero drag.

http://cafefoundation.org/v2/pdf_tec...4-2163-960.pdf

[Rokeby]

Very interesting.

Observations of an aerodynamics neophyte:

The 4-seat shape had a max diameter of 5 ft. and a useable length of
12-1/4 ft., a fineness ratio of 2.72.

In the Conclusions, the authors suggest that max efficieny would occur at a
fineness ratio of 6, for a useful length of 30 ft. with the same 5 ft. diameter.

I can't help but notice that the cross section of the fuselage shape, Fig. 14,
looks roughly like two flat-bottomed air foils placed together with the trailing
edges facing forward. In essence "flying" backwards. I suspect this
observation has little or no practical meaning.

I also note that the section of rotation is somewhat replicted by the roofline
of the Gen III Prius from the wheel wells up:



I guess that isn't surprising given the Prius' low Cd.

[NeilBlanchard]

More renderings; these are done by Robert G. Scott:







I'll take a look at it, Patrick.

Edit: that is *very* little to go on -- it for an airplane and it is a schematic 2D drawing. The nose is pretty pointy, and the back looks all wrong... The biggest trick in transferring airplane design to cars -- is the ground plane and the wheels. The Boxfish had those "worked out", and still had amazingly low drag.

I've spent about 9 months on this design so far, and I have made (relatively) drastic changes along the way, but I can't throw it all out now. I fit 5 humans into a package barely larger than the Fig 15 shows, and mine has wheels, a drive train schematic, safety considerations, construction methods, etc.

[NeilBlanchard]

Some additional renderings, by C. Michael Lewis:

[NeilBlanchard]

So, I've been sitting with the spelling "CarBŒN" for a little while now, and I'm not sure I like it, or that it has achieved what I was hoping. Besides, it is hard to use an extended character and web addresses don't "like" it...

So, the suggestion has been made to go in another direction (by an architect friend in CA named James Horecka, who has visited the Aptera offices and sent me a brochure). This is not exactly what he suggested, and I'll just float it and you tell me what you think:

CarBEN Franklin

Your feedback/reactions, please???

[NeilBlanchard]

Okay, we're gettin' *real* close to finish of the outside -- I'm going to try to model the seats and some of the structural stuff inside. Here's my own (somewhat clunky) renderings of CarBEN (Franklin?) Mk 3.2:









Besides redoing much of the side (twice), I've added better turn signals (think LED's) and marker lights, as well. Oh, and please notice the trailing articulated wheel panel is now a smooth arc, too! ;-) The blue sweep/lightening pinstripe was a suggestion that I am trying out -- what do you think?

[Patrick]

Originally Posted by NeilBlanchard

So, I've been sitting with the spelling "CarBŒN" for a little while now, and I'm not sure I like it, or that it has achieved what I was hoping. Besides, it is hard to use an extended character and web addresses don't "like" it...

So, the suggestion has been made to go in another direction (by an architect friend in CA named James Horecka, who has visited the Aptera offices and sent me a brochure). This is not exactly what he suggested, and I'll just float it and you tell me what you think:

CarBEN Franklin

Your feedback/reactions, please???

Well, since you asked. . .

I think CarBEN gives the wrong impression. You are emphasizing what you want to avoid or don't produce. You wouldn't name your car Gasoline. I think you should shoot for something that's the opposite, like noCarBEN. Or CarBENless. Or maybe Breathe or AIR. This gives a better impression of what the car is trying to do. If you want to still include your initials you could use something like NEBula or some other word that includes NEB or BEN but doesn't have the negative connotation of carbon. JMO.

[dbc1218]

I have been reading this post and have looked at your blog and would like to help move the project forward. I want to help create the first "rough draft" for the details of the car's construction. I have solidworks software and should be able to put something together fairly easily. I have a short background in vehicle design as well. I was on my schools SAE baja team during college and was the captain for the past three years. I designed, built, tested and broke two full cars during that time and feel I could contribute to this project. To get started could you send me a PM so we can exchange emails and drawings.

I am excited to get to help with carben because like you I too want to build my own vehicle from the ground up and think this would be a great way to gain some experience.

Doug

[NeilBlanchard]

Hi Doug,

I'll send you a PM right now. Here's the latest video: